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PeeDee
01-14-2007, 01:28 AM
Because I really wish we had a place, on AW, where we can natter on about the science of the world around us, some of which goes way beyond anything us meager sci-fi writers have even begun to cook up.

Here's a thread for it. I'll post a longer chatter about some fascinating creatures that live inside underwater volcano vents in a moment. It may take a second to type out. :)

PeeDee
01-14-2007, 01:34 AM
Right. So. The show I just watched, on my delightful Discovery HD, was focusing on a deep sea sub exploring active (and, more interesting) defunct volcanic fissures along the bottom of the Atlantic and Pacific, near the crevices of the tectonic plates.

What was fascinating were the HUGE swarms of creatures living on active volcanic fissures, which themselves are tall pillars that build and build themselves hundreds of feet tall as they boil away water, cool, leave deposits, and continue to spew.

All manner of creatures, in water that's 650 degrees, with almost four hundred PSI. There were delicate shrimp that lived to eat bacteria out of things which formed to look like bowls. The shrimp, who are not perhaps the brightest creatures, would dip in and out of the searing water, usually burning off their own exoskeletons and outer limbers.

...

What really fascinated me, though, were what happend when the volcanic fissures stopped spewing and went dead.

Of couse, all the millions of creatures who exist (impossibly) all died out. They couldn't move, they weree entirely dependent on this specialized enviroment, so they died out.

But when they showed footage of these defunct towers of sediment and volcanic ash....there are thin and glowing strands, like thick spiderwebs, stretched and draped across all of the sharp crags. And these creatures, huge and multi-legged and glowing pure white, who dispensed them.

Carrion eaters, of a sort. And so beautiful. I wish I knew what they were called, I'd find a picture of them to post.

veinglory
01-14-2007, 01:38 AM
I love the stuff around geological vents. That is where we found the first creatures in no way dependent upon the sun--and archeobacteria which are as difference from normal bacteria as they are from animals and plants. Crazy stuff.

PeeDee
01-14-2007, 01:45 AM
They sent a camera INSIDE the active volcanic tube and found inside, in temperatures and pressures that I didn't remember, but were unimaginably high. They were creatures, jelly like, in the shape of brains (really) with tentacles that sucked nutrients out of the nutrient intense water.

It was astonishing. It awed me more than most sci-fi has ever done. I'm a recent comer to science like this, and I'm blown away.

Saanen
01-14-2007, 01:48 AM
Have you seen the Blue Planet series? I think that's what it's called. They focus on the world's oceans, and one of my favorite episodes that I've caught explored the undersea volcano colonies. Just amazing and so strange and alien--yet here it is on our own planet. I just checked out a book on deepsea exploration at the library, which I hope will discuss it too.

Little Red Barn
01-14-2007, 01:49 AM
Wow! Just shows what creatures can adapt to...I'm impressed by this stuff as well.
Thanks Pete!

PeeDee
01-14-2007, 01:50 AM
It's this unimginable deep sea stuff which comes to mind when scientists point out that obviously, nothing can live on (for example) Io, because it's got no atmosphere and it's all volcanoes and ash and so on. Or on barren asteroids, or on Mars, or anything. There's no air, there's no water, there's no life.

There are places in OUR world where things which we couldn't comprehend in a million years -- which are closer to Cthulu than to science -- exist in manners that shouldn't be possible. How on earth does a jelly creature survive in water that's upwards of five or six hundred pounsd per square inch? That shouldn't be possible. But it is.

veinglory
01-14-2007, 01:56 AM
I saw open where mineral made a sort of heavier lake under the sea with those tube creatures and all this stuff around the 'shore' where the two types of water meet. It looked just like seaweed on a beach.

PeeDee
01-14-2007, 02:00 AM
I saw open where mineral made a sort of heavier lake under the sea with those tube creatures and all this stuff around the 'shore' where the two types of water meet. It looked just like seaweed on a beach.

I've read something about this. It pointed out that old wooden ships would only sink so far, which means in theory, they would be sailing along after a fashion on this heavier water at a depth that finally supported their weight.

Dead men sailing dead ships. It's a fun image.

I have no idea if it's true or not, though. If I weren't at work, I'd be posting all manner of links and photos to this thread.

Saanen
01-14-2007, 05:14 AM
I saw open where mineral made a sort of heavier lake under the sea with those tube creatures and all this stuff around the 'shore' where the two types of water meet. It looked just like seaweed on a beach.

Ooh, I saw that too! I'd almost forgotten it. It was the most eerie and surreal image I believe I've ever seen--what was a very obvious lakeshore with shells and so forth along the waterline and (as I recall) even ripples on the lake, and then a FISH swimming ABOVE the water. Wow!

Was that the same episode with the blue whale skeleton and those horrible eel-like fish that can actually twist themselves into knots to get a better purchase on the rotting flesh they eat?

veinglory
01-14-2007, 05:18 AM
That was the one. I need to watch more Discovery channel :) -- but I have been lured over the the white rapper reality show. :(

PeeDee
01-14-2007, 05:25 AM
I watched NOVA when I was a young warthog, but now I'm almost obsessively watching Discovery, and Discovery HD. And History Channel. I get three history channels, and all sorts of Discovery-sort channels. I'm in hog heaven.

I watched a wonderful show on Vikings and how they navigated the oceans once they got out of sight of land. It was also fascinating. They knew the world was round, they understood the use of stars, and they had this amazing thing that looked like a sundial, except they would carve semi-circle lines in it, and so long as the shadow from the sun stayed more or less along the curve of the line, they could determine what course they were on and plot their needed course from there. Quite a lot more than north, south, east, west. They could carve new lines to mark frequent trips, for example.

PeeDee
01-14-2007, 12:07 PM
I wanted this to be a general science thread covering all manner of sciences....

...except for the bits I post, because at the moment, I'm utterly fascinated by deep sea life and living conditions.

I just read this:


The elusive giant squid is one of the world's largest animals, reaching a length of up to 60 feet. It is the largest known invertebrate in the world.

The giant squid is a mollusk and is member of the cephalopod class, which includes the octopus and other squids. Very little is known about these mysterious animals because none have been seen alive in the wild.

Most of what we know about them comes from the bodies of dead squid that have washed ashore or been pulled up in fishermen's nets. These animals are carnivores, and will eat just about anything they can catch.

During World War II, stories from the survivors of sunken ships tell of shipmates being eaten by these creatures in the dark of night. There have even been reports of giant squid reaching out of the water and pulling men off small boats. None of these reports have been officially verified, but they paint a picture of a powerful predator.

The squid's eight long tentacles have strong suction cups which they use to hold on to their prey. A sharp, powerful beak finishes off their helpless victim with eerie efficiency. The giant squid appears to be a favorite meal for the sperm whale.

They have been found in the stomachs of dead whales and some these whales bear scars from the squid's suction-cupped tentacles.

I remember the giant squid (or was it a kraken? I must go research krakan's now) from 20,000 Leagues Under the Sea, and I remember it terrified me. Particularly in the old movie versions. Reading about it is fascinating, and certainly spooky. Can you imagine it just reaching up and eating people, snapping them off small boats like delicacies off a tray? Urk.

PeeDee
01-14-2007, 12:10 PM
A question, that maybe someone will know the answer to around here:


Only soft body animals can live at those depths such as jellyfish, sea anemones and other soft bodied animals.

Why is that? Thus far, all I have seen seem to indicate that the deeper you get, the softer-bodied the creatures get. Wouldn't it be logical to assume that you would need a harder and more durable exo-skeleton to survive the intense PSI down that deep....?

limitedtimeauthor
01-14-2007, 12:14 PM
Limitedtimeauthor reads all this fascinating scientific stuff and thinks to herself: Hmm. I haven't eaten at Red Lobster in a while.)

PeeDee
01-14-2007, 12:22 PM
That both fails to answer my question and makes me hungry for cheesy garlic biscuits....

Peggy
01-14-2007, 12:50 PM
Why is that? Thus far, all I have seen seem to indicate that the deeper you get, the softer-bodied the creatures get. Wouldn't it be logical to assume that you would need a harder and more durable exo-skeleton to survive the intense PSI down that deep....? My guess is that the pressure is so extreme that exoskeletons strong enough to withstand the external conditions would be difficult to grow, particularly if there were joints to allow mobility. There are deep sea tube worms that live in hard "shells", but they are anchored to rocks. To be able to both move around and live under high pressure, a soft deformable body (without any internal air pockets) might be the most practical construction.
It's this unimginable deep sea stuff which comes to mind when scientists point out that obviously, nothing can live on (for example) Io, because it's got no atmosphere and it's all volcanoes and ash and so on. Or on barren asteroids, or on Mars, or anything. There's no air, there's no water, there's no life. I find "extremophiles" fascinating - not just the deep sea critters, but those that live at very high pH or low pH, in high temperature thermal vents or subfreezing temperatures, or eat oil or plastic or ammonia. I think all we can really say about life on Io or Europa or Venus is that it would be unlike any we know of on earth.

dpaterso
01-14-2007, 01:10 PM
Yeah I think we've all been fascinated by big squidy things and looked up the stories and stats. Bloody scary. They make sharks look like liberals who're prepared to sit down and listen to your viewpoint.

I've employed squids, lobsters and crabs (the big ones with claws, not the itchy little ones you need a cream for) to stunning effect in my many and varied Sci-Fi tales, unfortunately my avid readers have responded with gales of laughter rather than applause, the peasants.

Fluids don't compress* so a soft fluidic body seems logical for the immense pressure of the lower ocean depths.

*Oh go on, prove me wrong then.

-Derek

Saanen
01-14-2007, 07:05 PM
Soft-bodied jellies and fish don't squish under deep-sea pressure because they're the same pressure inside as out. I've heard that many of them will virtually turn inside out when brought quickly to the surface, though, because of the change of pressure--although that may be a myth.

PeeDee
01-14-2007, 08:01 PM
Once you realize they haven't got internal air pockets, that makes perfect sense. I can see why they'd be able to live on those depths. The matter of the heat still fascinates me (why isn't organic material burning off at close to a thousand degrees?)

A fun sci-fi theory: What if we found a deep sea creature which we were able to transport and then set free, deep inside Jupiter's atmosphere, full of chemicals it can eat and live in, at a pressure it can survive at. Wouldn't that be cool? It wouldn't make a shabby sci-fi story, I think.

Fluids don't compress? So the ocean water would have the same parts per inch at 1000 feet down, as it does at 20 feet? So why does the PSI increase?

dpaterso
01-14-2007, 08:35 PM
Fluids don't compress? So the ocean water would have the same parts per inch at 1000 feet down, as it does at 20 feet? So why does the PSI increase?
The weight of all the water above, pressing down!

-Derek

PeeDee
01-14-2007, 10:19 PM
The weight of all the water above, pressing down!

-Derek

Sorry, I think I phrased that poorly. I meant, why is it with the increasing pressure of water as you get further and furthe down, why doesn't the water compress on a basic level?

I guess it can't. I guess you can't exactly have the molecules and atoms breaking down.

Hm. Hm. Hm.

Pthom
01-15-2007, 01:59 AM
Once you realize they haven't got internal air pockets, that makes perfect sense. I can see why they'd be able to live on those depths. The matter of the heat still fascinates me (why isn't organic material burning off at close to a thousand degrees?)Because in order to burn (another term for oxidize) a substance needs free oxygen molecules. The oxygen in water is bonded too well to hydrogen. (I think. Better chemists are welcome to correct me.)


A fun sci-fi theory: What if we found a deep sea creature which we were able to transport and then set free, deep inside Jupiter's atmosphere, full of chemicals it can eat and live in, at a pressure it can survive at. Wouldn't that be cool? It wouldn't make a shabby sci-fi story, I think.I remember reading a piece by Carl Sagan, once, where he postulated beings on Jupiter might indeed be a lot like our sea jellies. Or, in the upper portions of the atmosphere, more like bags of gas (hot air balloon-like). Right up David Brin's alley. ;)


Fluids don't compress? So the ocean water would have the same parts per inch at 1000 feet down, as it does at 20 feet? So why does the PSI increase?Think of it this way. Under normal experience, bricks don't compress much either. I mean, they don't change shape or anything in buildings that are several hundred feet tall. But, lie on your back and start piling bricks on your belly. You squish out way before you get hundreds of feet worth of bricks on top of you. Even if you take a sea jelly and put it on the sidewalk, it squishes out before you get more than a couple bricks on it.

So why don't they squish to nothing at the bottom of the sea? Because the sea is pushing on them equally in all directions. And, they're made of almost entirely of water, themselves. Somewhere else, you mention that beings with pockets of air in them (such as humans) can't survive well at great depths. That's true. Mainly because the air can't easily be brought up to the same pressure as the surrounding water. It is this high gas pressure that gives deep sea divers the bends when they try to decompress too rapidly.

AzBobby
01-15-2007, 02:15 AM
Small correction on one of the quotes above: Squid have ten tentacles, not eight... except...

On a cable doc the other night, which was about capturing the first photos ever taken of the giant squid alive, the narrator described the limbs -- unless I heard or remember wrong -- as eight arms and two tentacles. The two called tentacles are the two longer ones most squid have. These seem to be used for more grabbing and wounding of prey than the other, shorter eight. (Are tentacles distinguished by the presence of the suckers, maybe? The long tentacles of the giant squid have some mean, sawtooth suckers at the ends.) That was the first time I had ever heard that terminology. But the rest of my life prior to that, I had heard squid have ten tentacles, with two longer than the other eight.

Ah, since typing the last paragraph I looked up squid in Wikipedia and they repeat what the show said -- squid have only two tentacles. The other, shorter eight tentacle looking things are "arms." Well that's ink on my face.

From the looks of it, the giants are normally miles down. I imagine most of them get eaten immediately after they die, what with herds of sperm whales diving for them. That must explain why the remains they show scientists studying on these shows never seem to be the sailor-grabbing size from the cool sea monster stories of yore.

Oh, then there's a whole different species called "collosal squid" that is believed to grow even bigger than the giant squid.

benbradley
01-15-2007, 03:06 AM
Fluids don't compress? So the ocean water would have the same parts per inch at 1000 feet down, as it does at 20 feet? So why does the PSI increase?

The term fluids refers to both liquids and gases. Gases do compress relatively easily, and usually follow Boyle's Law (go ahead, google it).

Liquids do indeed compress a very small amount with an increase in pressure. The PSI increases as you go deeper because of the weight of the liquid above it pressing down on it.

Here's a little info on how much water and a few other liquids compress with an increase in pressure:
http://hyperphysics.phy-astr.gsu.edu/hbase/tables/compress.html
Here's more than you wanted to know about the physical properties of water:
http://www.piercecollege.edu/offices/weather/water.html

When I was a kid I wanted to be a scientist, but I only turned out to be an engineer.

ChaosTitan
01-15-2007, 03:17 AM
I have been following this thread, and am amazed that I actually understand ninety percent of what y'all are talking about! And this coming from a girl who barely squeaked by in Earth Science and Chemistry.

:LilLove:

Keep it comin'!

pconsidine
01-15-2007, 03:32 AM
It's funny - most of my geeky fascinations are with math and physics, but that kind of information is much harder to come by in the popular culture. But when it does come up, it can be pretty fascinating, even to normal people.

I remember quite a few years ago, I made my ex and a friend of ours watch a Nova special about the solving of Fermat's Last Theorem (http://en.wikipedia.org/wiki/Fermat%27s_Last_Theorem). The height of geekery, to be sure. But the story of the solution (7 years of solitary work, carried out in complete secrecy, only to have a problem found when the proof was announced) is such human drama that even if they only understood a tenth of the details, it was still a fascinating story.

And if you ever want to talk about Variable Speed of Light theories, give me a ring. ;)

PeeDee
01-15-2007, 04:23 AM
And if you ever want to talk about Variable Speed of Light theories, give me a ring. ;)

I'd like to hear about it, actually. I'm going nuts on this science stuff. I understood so little of it in school (admittedly, because I paid not enough attention) and now, I'm fascinated and ravenous for it all.

I'm reading Boyle's Law and telling my wife (who is probably not as agog as I am). I'm about to go Google Collosal squid.

I love the image of a herd (flock? School?) of Sperm Whales diving for giant squid and eating them. Giant squid are sixty feet or so in length. Just the sheer size of it, and then have whales diving not only boggles my mind, but deeply intimidates me.

One of the things that always kept me from going over the edge of the island when I lived on St. Croix (because you could; swim out far enough, and look down, and there's nothing below you but black, black water) was the thought of fish, bigger than my mind could handle, swimming at me. A sense of hugeness has always lent itself to fear in my mind.

pconsidine
01-15-2007, 05:56 AM
It's funny – in my senior year of high school, my choices for college were either fine arts or math. Shoulda went with math. It might have saved me from this whole writing fiasco. ;)

By the way - while you're out there Googling, look up giant otters. I used the giant otter as the basis for one of the monsters in a magical fantasy script I wrote ages ago. If I recall correctly, they're unique to the Amazon River and effing scary.

Edited to add: Apparently the image of the giant otter that scared the crap out of me in the first place isn't online anymore. Tragic. :(

a tree of night
01-15-2007, 06:31 AM
a herd (flock? School?) of Sperm Whales

I believe "pod" is the aggregate you're looking for.

jsh
01-15-2007, 09:06 PM
Right. So. The show I just watched, on my delightful Discovery HD, was focusing on a deep sea sub exploring active (and, more interesting) defunct volcanic fissures along the bottom of the Atlantic and Pacific, near the crevices of the tectonic plates.
Was it James Cameron's Aliens of the Deep? I saw that at an IMAX theater. What struck me most was the remark that these animals are completely independent of the surface world; i.e., if the sun was snuffed out today, those creatures down there wouldn't know or care.

PeeDee
01-15-2007, 10:46 PM
Was it James Cameron's Aliens of the Deep? I saw that at an IMAX theater. What struck me most was the remark that these animals are completely independent of the surface world; i.e., if the sun was snuffed out today, those creatures down there wouldn't know or care.

*checks*

Yes! Narrated by Ed Harris. I wish I'd seen it in the IMAX. The last sea show I saw in the IMAX was narrated by Johnny Depp and Kate Winslet, and was in 3D. It was interesting for being 3D, and showing lots of fish on a big scale, but there wasn't much of an interesting documentary nature in it.

A fascinating bit that my wife and I noticed. At the local aquarium (in the Mall of America; gorgeous aquarium) they have a round tank full of jelly fish of a decent size that swim around and live whatever lives that jellyfish lead.

They're blue. They are most definitely blue. Electric blue, if I had to be speffic.

But what interests me a great deal is, every time we took a digital picture of them -- flash or no flash -- they came out purple. Electric purple, if that's a color.

I love that. We took all sorts of pictures just to watch the color change.

If I were younger (well, I'm not that old) and inclined to dive back into school, then I think I would look into marine biology or something. THis is fun.

a tree of night
01-16-2007, 12:22 AM
Unless you tell it otherwise (adjusting the white balance), your digital camera is going to expect a specific range of color temperature for the incoming light and the light coming out of jellyfish tank is probably below that range (cooler = redder). You can get similar effects in everyday photos by adjusting the white balance out of the correct range. Or you can just Photoshop your family portraits to your favorite shade of green if you don't have a white balance setting.

The same thing will happen with a film camera, but you'd correct it with an appropriate filter.

Kentuk
01-16-2007, 12:41 AM
It's raining fish and seaweed. There is ball lightning floating by and red raining is falling.

Judg
01-16-2007, 02:41 AM
I remember reading a piece by Carl Sagan, once, where he postulated beings on Jupiter might indeed be a lot like our sea jellies. Or, in the upper portions of the atmosphere, more like bags of gas (hot air balloon-like). Right up David Brin's alley. ;)I just read Jupiter by Ben Bova in which there were gigantic medusas floating in the Jovian atmosphere. I was quite annoyed with him for not acknowledging his debt to Arthur C. Clarke on that point, (short story, "A Meeting with Medusa") and now I find out Carl Sagan did the same thing. *grumble, grumble* Whatever happened to intellectual integrity? *grumble, grumble*

pconsidine
01-16-2007, 03:36 AM
Whatever happened to intellectual integrity? *grumble, grumble*Awww...they're so cute when they're young, aren't they? ;)

AzBobby
01-17-2007, 01:16 AM
Hey Pete, giant squids aren't 60 feet in length, although the overestimate appears in print sometimes. The biggest ones are around 40, so say the seageeks, and collosal squids theoretically a little longer, though not much (but interestingly much bigger in the mantle section, with shorter limbs relative to the giants). But there's always a freakishly big specimen of everything lurking somewhere in the unknown...

Now here's some geekery that excited me today. During lunch I caught a Science Channel doco about Deep Space One, a probe that went out to meet an asteroid sometime in the last couple years. The big advancement they focused on was the development of automated navigation for it -- they learned a great deal from the mission about what to correct in such probes of the future.

The exciting part to me was the reminder that in a culture where it is hard to argue in favor of the expense of the space program, there remains one slight possibility that this kind of technology could save the whole planet from extinction. If an auto-navigating craft is sent to intercept an asteroid or comet on a collision course with earth, it will be much harder to grumble over the billions of dollars spent in preparation for the occasion. And it could happen any time. If that comet (or whatever object it was) that impacted a barren (by sheer luck) area of Siberia a century ago hit a certain part of the ocean, the resulting tsunamis could have wiped out several major cities. A slightly different size and location, and such a thing could wipe out all surface life. So, rare as it may be, it does happen, and has... And it would be fun to absorb some expert discussions on exactly how such an object in space could be safely diverted. For example, I've heard that the problem with simply blowing it to pieces without a smart plan is that it might turn one asteroid into a dozen, all continuing to hurtle in the same path toward earth.

PeeDee
01-17-2007, 02:47 AM
That comes as a relief to me, about the giant squid, because the more and more reading I was doing online for them, the less and less I was finding that actually pointed toward a sixty foot length.

I've very strongly in favor of.....not necessarily the NASA Space Program, but of going to space in general. I believe that we need to get to space, and I believe that waiting passively for a few people to get there isn't how to do it Unfortunately, I don't see that changing until the situation on Earth is dire.

People went to America to avoid persecution and Not Get Hanged. People went to Australia as prisoners. We rushed to the moon to beat out the other countries rushing to the moon.

Without something that makes us sit up and go "Oh yeah?" we're not going to get there. Not yet.

...

It DOES fascinate me, the thought of an asteroid slamming intot he earth. I was interested in it years ago, and then we got movies like Armageddon and Deep Impact and I thought "Good lord, crushing waves take me now."

I think that it would be more important not to blast the asteroid into shards (which, as you point out, would just hit us and pepper us anyway) but to impact the asteroid in such a manner that it knocks it off course.

Ray Bradbury has this great book title, "Too soon from the cave, too far from the stars." I think that's probably very true.

There's also a great Babylon 5 quote from the first season about why it's important to go to the stars and remain there. If I can find it, I'll post it.

Judg
01-17-2007, 05:03 AM
Awww...they're so cute when they're young, aren't they? ;)LOL. Thanks for the giggle, er guffaw. Yes, I was, too many decades back. Now I'm just cranky...

benbradley
01-17-2007, 07:13 AM
That comes as a relief to me, about the giant squid, because the more and more reading I was doing online for them, the less and less I was finding that actually pointed toward a sixty foot length.

I've very strongly in favor of.....not necessarily the NASA Space Program, but of going to space in general. I believe that we need to get to space, and I believe that waiting passively for a few people to get there isn't how to do it Unfortunately, I don't see that changing until the situation on Earth is dire.

People went to America to avoid persecution and Not Get Hanged. People went to Australia as prisoners. We rushed to the moon to beat out the other countries rushing to the moon.

Without something that makes us sit up and go "Oh yeah?" we're not going to get there. Not yet.

...

It DOES fascinate me, the thought of an asteroid slamming intot he earth. I was interested in it years ago, and then we got movies like Armageddon and Deep Impact and I thought "Good lord, crushing waves take me now."

I think that it would be more important not to blast the asteroid into shards (which, as you point out, would just hit us and pepper us anyway) but to impact the asteroid in such a manner that it knocks it off course.
I don't see "impact" as a good word here either. We're not sure how solid or dusty an asteroid is. To keep it in one piece and still move it, a ship will probably need to softly "land" on it, then turn on its engine to lightly push on the thing for several weeks to "nudge" its course away from Earth. This requires that the projected impact be many months, if not years, away. If we suddenly find an asteroid a hundred feet or larger, and it's only days from hitting Earth, I think the best we can hope for is to launch a nuke at it and hope for the best with the size of the fragments are and where they go. There are groups running sky surveys looking for all these small asteroids so we can catch them years or decades before they impact Earth, while there's a good chance that something can be done about them.


Ray Bradbury has this great book title, "Too soon from the cave, too far from the stars." I think that's probably very true.

There's also a great Babylon 5 quote from the first season about why it's important to go to the stars and remain there. If I can find it, I'll post it.
For decades there have been arguments about what the "current" space programs should do, manned vs. unmanned - there's been a lot of stuff done with unmanned probes that have done flybys or landings on many/most of the planets as well as a comet or two, whereas people have 1. gone into low Earth orbit, 2, gone to the Moon, and 3. continued to go into low Earth orbit, at probably many times the expense than all the unmanned programs combined.

When you think what it takes to get a metal box with people in it 1) up 110 miles above Earth's surface, and 2) moving horizontally at seven miles PER SECOND so that they stay in orbit, and then 3), 4)... get them back safely without too much acceleration/deceleration (there's only so much a human bean can take), it's rather an achievement that there have been over 100 Shuttle missions with only two of them having gone horribly wrong. An likewise for previous NASA programs and the manned missions of other countries.

It's hard to imagine there being large numbers of people (more than a few dozen) in orbit or especially on Moon or Mars bases in the next several decades, just because it's so hideously expensive to get people there and back. I don't see any substantial increases in space bugets, despite when was it, the State of The Union speech one year ago(?) when Bush announced a return to the Moon and a mission to Mars. I won't believe it 'till I see it.

OTOH, if there were a sufficiently large amount of funding guaranteed to the task (hoping not to make this thread veer off course, but the figure of $87 Billion as an amount dedicated to a particular task comes to mind), I think we'd have no problem sending people to Mars.

Funding for big, long-term science projects is too often a political football that opponents see as "pie in the sky" stuff. The big supercollider thing in Texas that was cancelled comes to mind.

Here's a Mars option I've not heard of, though I've not read any "space policy" forums where ideas like this might have been discussed: it may be cheaper to make it a one-way mission and keep sending unmanned "care packages" of food, water and oxygen than to do the traditional assumption that they'll return after a fixed time like the Apollo astronauts did from the Moon. It won't cost nearly as much to send small samples of soil and rocks back from Mars as it would to have the extra fuel and resources to bring the people back. But this idea may be a little bit too politically incorrect. And with the history of funding for things like this, perhaps it would be a reallly bad idea - I can imagine funding being cancelled just as the ship enters Mars orbit, having just used up the fuel for a return trip.

AzBobby
01-17-2007, 08:42 AM
People went to America to avoid persecution and Not Get Hanged. People went to Australia as prisoners. We rushed to the moon to beat out the other countries rushing to the moon.

Without something that makes us sit up and go "Oh yeah?" we're not going to get there. Not yet.

That's a very reasonable prediction, which creeps me out... It means we might scramble to get off this planet only with the worst and most desperate timing, a "When Worlds Collide" kind of situation, and the most organized of space programs will only provide fare for a few people.

Here's another prediction -- nanotechnology has to catch up with space travel for humans before it really takes off and gets past the problems already raised, mainly the fact that it's too expensive and dangerous to be either practical or popular for many years to come. This is still a bit of a fantasy angle at this time, but it seems only nanotechnology of the most rapid and efficient kind dreamed of in our scifi tales could manage the tricky engineering involved in the construction of, say, a reliable space elevator, atmospheric domes and space stations of any size to comfortably house entire communities off the earth, and maybe even the terra-forming of other worlds like Mars. The speed of space travel won't improve much thanks to physics, but this will matter less and less as our life spans increase beyond reckoning.

PeeDee
01-17-2007, 10:00 AM
I always thought space elevatars were the wonkiest ideas out there. They just boggle my mind.


Ben....you're right about the asteroid. "Impact," is a poor word, but then, I'm a pretty poor man of science. I may write sci-fi, but I go toward the Heinlein angle rather than the Asimov angle, if you follow me (I do people; I don't usually do technology and science, especially if I don't understand it). This stuff fascinates me, but I know little about it.

However, wouldn't launching a nuke at the asteroid and potentially sending smaller shards down on earth still dump radiation on us from the nuclear explosion? I mean, some of the radiation would bleed off into space and into the upper layers of our atmosphere, but would all of it bleed off...? Theoretically?

...

I do realize the huge cost and effort that is put into our space program, and I hope I didn't come across as belittling them. Not at all. NASA does a damn, damn good job with what they're given -- which is never enough -- and out of sheer bloody-minded stubbornness, they keep doing good things even when the world's making fun of them.

I'm not saying NASA's no good, I'm saying NASA's not enough. The contest to see which private individual or company could build a space boat is a great idea (and Amazon's Jeff Bezos did some interesting stuff) and we need more of that.

We have a reason to go into space right now like a twenty-year-old has a pressing need to quit smoking. He may want to, he may know he needs to, but he keeps putting it off and putting it off because...you know....it's not bad yet.

It's the same wiht going to space. We want to, yeah, sure, youbetcha. We need to, I guess, in the long run dude....but right this second, we have wars to fight, people to toast, contests to watch, clothes to wash, dinner to make, and so on.

People can do some powerful things when, as a mob, they get fired up over something. If a mob fired up over space flight like they fired up over Vietnam, or Iraq, or what-have-you, I bet you we'd be on Mars right now.

Anyway, I'm not criticizing those who ARE going into space right now. If I criticize anyone, it's a general desire for people to have a stronger drive toward the big thing that I want.

Pthom
01-17-2007, 11:15 AM
... If we suddenly find an asteroid a hundred feet or larger, and it's only days from hitting Earth, I think the best we can hope for is to launch a nuke at it and hope for the best with the size of the fragments are and where they go. Even if such a nuke were to pulverize the asteroid, it can't destroy the mass, or very much of the initial trajectory, so instead of one big chunk making a big splash in Enid, Oklahoma, it would rain down the same amount of energy over a larger area, like all of North America. And, because of the vastly greater number of pieces, there is greater opportunity for oxidation as more of the asteroid burns up before striking the surface. Greater oxidation = less free oxygen to sustain life. No matter what, if a 100-foot-diameter asteroid was on a collision course with Earth, the best defense may just be prayers.
_ _ _ _

ETA: I shoulda read PeeDee's comment regarding this before replying. Ben's notion that if we're gonna blow up an asteroid or make any other attempt to deflect its orbit, we'd better find one far enough away to give us years of time to do so, is spot on.

a tree of night
01-17-2007, 07:12 PM
I'd really like to see a fully international space effort, funded by pooled government and private resources, but without any political influences, and open to any scientist. If you read the Rogers Commission report, what Feynmann had to say about his research and the report itself, and then the CAIB report, it becomes very apparent that there is a pervasive culture in NASA that hasn't really changed despite the accidents. The political influence overwhelms science and basic common sense to the point where progress is limited and safety is at risk. It really is amazing that they have achieved as much as they have, but one has to wonder how things would have gone differently if the management chain had been filled with people with the appropriate scientific knowledge instead of political agendas.

AzBobby
01-17-2007, 11:08 PM
We have quite a chocolate box of space objects out there. I'm sure the world-destruction prevention strategy will depend on what the asteroid or comet or whatever it is is made of. For example, it's interesting how they can't find any pieces of that thing that hit Siberia in 1908 -- leading to the debated theory that it was a comet made mostly of ice which vaporized. Whatever it was, it appears certain the explosion occurred above ground before the thing made any solid landing, based on the cool butterfly pattern with which it flattened the forest beneath it.

When the time comes, the experts might debate whether nuclear explosions are necessary to divert or destroy an object on collision course, depending on what it's made of. (Maybe we can just splash some vinegar on it? "Hannibal!")

It still boggles my mind that such a tremendous natural disaster just happened to occur with such a sparse population around to witness it, even from afar. Many natives reported the Siberian explosion, but we're not even sure if it killed a single person, although it was a mightier blast than our most powerful nuclear bombs. The place was so remote that no expeditions bothered to investigate it until the 20s (of course, there was plenty to keep the Russians busy otherwise in the years between). What crazy luck we live with.

PeeDee
01-17-2007, 11:13 PM
....I know nothing about this Siberian mystery explosion, but it sounds fascinating. I'm googling to no avail. I don't suppose you have links you can point in my direction? That sounds fascinating.

readlorey
01-17-2007, 11:14 PM
I watch TV shows that tell you about nature and space and animals and people and stuff. And ancient history. I find it all fascinating!

AzBobby
01-18-2007, 01:33 AM
I think I first learned of the Siberian explosion from the series Cosmos. Despite the sensational nature of a comet (or giant meteor) hitting earth, it was below most people's radar for decades because WWI, the Russian Revolution, and so on dominated world events shortly afterward. Plus, like I said, although meteorologists noticed its effects the impact occurred as much in the middle of nowhere as the planet had to offer.

Just Wikipedia'd it. It's called the Tunguska Event (I had long forgotten that name). See http://en.wikipedia.org/wiki/Tunguska_event ... Googling the subject becomes a lot easier with that name handy.

Peggy
01-18-2007, 01:39 AM
....I know nothing about this Siberian mystery explosion, but it sounds fascinating. I'm googling to no avail. I don't suppose you have links you can point in my direction? That sounds fascinating. The key word is Tunguska.

http://en.wikipedia.org/wiki/Tunguska_event

(If you watched X-Files, you'd know that it was the source of mysterious alien oil-like microbes that can take over the human body.)

Peggy
01-18-2007, 01:48 AM
Ha, Bobby beat me to it. That's what happens for getting sucked into the articles. There is a lot of conspiracy theory-type sites connecting Tunguska with UFOs. My favorite, though, is the theory that the explosion was caused by the test firing of a weapon by Nikola Tesla.
http://prometheus.al.ru/english/phisik/onichelson/tunguska.htm

Tesla's writings have many references to the use of his wireless power transmission technology as a directed energy weapon. These references are examined in their relationship to the Tunguska explosion of 1908 which may have been a test firing of Tesla's energy weapon.

This article was first published in a different form in 1990. The idea of a Tesla directed energy weapon causing the Tunguska explosion was incorporated in a fictional biography (1994), by another writer, and was the subject of a Sightings television program segment.

Pthom
01-18-2007, 04:48 AM
Tesla's exploits were a favorite theme for writer Spider Robinson, but that's science fiction and this is .. (ahem).. science fact

factoids?

PeeDee
01-18-2007, 05:25 AM
Nikola Tesla is a very interesting person (even when he's played by David Bowie, in The Prestige). He's fun to read about.

I've got some interesting Siberian reading to do when I get home. How very, very cool....

benbradley
01-18-2007, 05:59 AM
I've read articles about the 1908 Tunguska event (don't remember where, and it's been a long time). There's been lots of speculation on what it might have been. One idea is it may have been something that went straight through the Earth and come out the other side (probably an ocean, since Earth is 2/3rds ocean). Thinking about it now, that seems unlikely, not just because of the apparent in-air explosion mentioned, but also it seems likely a similar explosion would have happened at the exit point, and if it came out in an ocean it would have created a large tsumani that would have been reported long distances away.

OTOH, this article describes two recent (1993) events of small objects going THROUGH the Earth. This freaked me out a bit when I first read it. These were much less dramatic and energetic than the Tunguska event, and apparently no one noticed at the time, but they left a seismic record, which was how they were found:
http://www.wired.com/wired/archive/11.02/matter.html?pg=1&topic=&topic_set=

...
It still boggles my mind that such a tremendous natural disaster just happened to occur with such a sparse population around to witness it, even from afar. Many natives reported the Siberian explosion, but we're not even sure if it killed a single person, although it was a mightier blast than our most powerful nuclear bombs. The place was so remote that no expeditions bothered to investigate it until the 20s (of course, there was plenty to keep the Russians busy otherwise in the years between). What crazy luck we live with.
I recall reading, perhaps in relation to the 1908 event, or perhaps unrelated, that human population takes up a relatively minor part of the Earth's surface (only 1/3 the surface is land, then there's the area around the poles which has virtually no population), so the chances of something hitting Earth at a random point landing on even a sparsely populated area is less than you might think. If it HAD hit closer to population, it would probably have been investigated sooner and we might know more about it.

Pthom
01-18-2007, 11:02 AM
But volcanos exist because of magma being pushed up to the surface, which happens along plate boundaries, especially(?) at subduction zones, right?
I'm going off 10th grade geography here. It was a while ago.
Volcanos such as the Pacific Rim ones (Pinatubo, Mt. Fuji, Denali, Ranier, St. Helens, Shasta, to name a few) are exactly that.

But the islands of Hawaii and the great shield volcano that is expressed today in Yellowstone National Park, are not. Those exist because of thin areas in the mantle that remain stable relative to the Earth's core, but appear to move as the continental plates move over them. Thus, millions of years ago, the hot spot of Yellowstone was under Idaho and before that, Oregon. And as the Pacific plate moves to the northwest, Hawaii gets new islands building at its southeast.

I don't know what causes Mt. Etna in Sicily, but it's a volcano.

I do know that mountains like the Rockies are created by uplift, that so are the Himalayas and the Alps, and that the great sandstone structures in the four-corners area of the American southwest are ancient sea beds that were thrust up and then eroded away.

I also know that it's so warm now on this planet that the glaciers of Kilimanjaro and Mt. Hood (both volcanos) are diminishing rapidly.

Now I just happened on most of that information by visiting some of those places, by being a couch potato and watching TV shows like NOVA, and reading (for no other reason than entertainment) such periodicals as Scientific American, Audobon, Science News and National Geographic. It ain't research necessarily, but the information is now stored in strange little electo-chemical corners of my mind ready for hauling out just for occasions such as this.

:D

PeeDee
01-18-2007, 11:06 AM
Volcanos such as the Pacific Rim ones (Pinatubo, Mt. Fuji, Denali, Ranier, St. Helens, Shasta, to name a few) are exactly that.

But the islands of Hawaii and the great shield volcano that is expressed today in Yellowstone National Park, are not. Those exist because of thin areas in the mantle that remain stable relative to the Earth's core, but appear to move as the continental plates move over them. Thus, millions of years ago, the hot spot of Yellowstone was under Idaho and before that, Oregon. And as the Pacific plate moves to the northwest, Hawaii gets new islands building at its southeast.

How interesting. Neat-o. So that means the shield volcano in Yellowstone is still moving today? I mean, in a few hundred (thousand? million?) years, it's going to keep working its way across America?

I didn't know Hawaii got new islands built, presumably over a very long time. That's interesting. Admittedly, I know little about this stuff, but I thought the land masses were what they were, breaking apart and joining together now and then but hardly gaining or lose land.

Shows what I know... :)

Pthom
01-18-2007, 11:22 AM
the shield volcano in Yellowstone is still moving today? I mean, in a few hundred (thousand? million?) years, it's going to keep working its way across America?I think so, yes. In millions and millions of years, it might reach the great lakes. Think of the geysers then!

BTW, I found out that Mt. Etna in Sicily is a real odd ball volcano (http://boris.vulcanoetna.com/ETNA_evolution.html).


I didn't know Hawaii got new islands built, presumably over a very long time. That's interesting. Admittedly, I know little about this stuff, but I thought the land masses were what they were, breaking apart and joining together now and then but hardly gaining or lose land.Maybe you weren't aware then, that the largest mountain on the planet is Oahu (based on its measuring its height from the seabed), even larger than Mt. Everest. Denali (the mountain formerly known as Mt. McKinnley) is even larger than Mt. Everest is. It's just that Everest starts being a mountain a waaaaay up there on a pile of what used to be India and Mongo...ah, Tibet. sumpin.

And land areas change significantly, even in our lifetimes. The coast of Oregon (the state where I live) is generally eroding away. I know of places where as a kid I used to hang that are now completely gone, fallen into the sea and pulverized into sand. The Mississippi delta (of recent fame) is an area that once was continually expanding into the Gulf of Mexico--halted somewhat by man's intervention--because the river and its tributaries carry bits of over half of North America along.

Former Vice President Al Gore's recent documentary on global warming would have us believe that we are in dire trouble and that without care, we will soon be forced to relocate over 90% of the world's population away from coastal lands. Well, he's right on both counts. But don't buy your water wings just yet. The rise in sea level due to melting of the ice caps will take decades, if not hundreds of years to occur. We probably have time for that event. What we don't have time for is to slack off and not begin doing something immediately to stave off the causes of global warming and associated ills.

Peggy
01-18-2007, 12:48 PM
I recall reading, perhaps in relation to the 1908 event, or perhaps unrelated, that human population takes up a relatively minor part of the Earth's surface (only 1/3 the surface is land, then there's the area around the poles which has virtually no population), so the chances of something hitting Earth at a random point landing on even a sparsely populated area is less than you might think. If it HAD hit closer to population, it would probably have been investigated sooner and we might know more about it. But oceans cover most of the earth, and I'd think that an asteroid or similar hitting the ocean have the potential of creating a massive tsunami.
Tesla's exploits were a favorite theme for writer Spider Robinson, but that's science fiction and this is .. (ahem).. science fact I have to confess that I first heard of Tesla's odder side via one of the Callahan books. It did inspire me to look up more facts - factoids? - about his life.

PeeDee
01-18-2007, 06:45 PM
I have to confess that I first heard of Tesla's odder side via one of the Callahan books. It did inspire me to look up more facts - factoids? - about his life.

"odder" side? For once, all I know about the man are his experiments (which fascinate me) with electricity....

...

How dense a metal, or rock, would you have to be to pass straight through the earth? How fast would you have to be going? I mean, even bullets are many times stopped inside a human body just by the bone structure, and that's nothing compared to a rock slamming into the pretty-hard-to-me surface of the earth. On top of that, it would need the consistent momentum to slam not only through the Earth's crust, but to sludge its way through the planet core, and then slam BACK through the crust again (and if it did it in the ocean, than) sludge UP through the ocean, fighting gravity, and continue onward the other side.


10 tons squeezed into something about the size of a red blood cell.

Even so, even with burning a tunnel and splitting molecules (which is fascinating), it would have to be going pretty damn incredibly fast to break ten tons free of our gravity field, wouldn't it?

What an interesting article. Though it's worrying to think of the earth as this full of holes, especially the ones that go straight through. Sort of. I suppose the lava (and the land, for that matter) would just go back where it was, more or less.

I'll stop babbling now. :)

MidnightMuse
01-18-2007, 07:40 PM
Do you think it's even possible for something - anything - to not only hit the earth, but then pass completely through it? Don't you think that action alone, considering the forces necessary, would simply break the planet apart?

I found it amazing (and I admit, it was from watching Mythbusters) how water impacts the projection of a bullet. Just a few feet of water can completely stop even a 55 caliber. So, assuming something dense and small slammed into the earth, if it hit the oceans the trajectory would be drastically interfered with. If it hit land, in order to pass through the land, and all the other layers, into the core, and through the other side - I can't even fathom the density we'd be talking about.

But even as I say this, I'm thinking it might be possible if said object were small enough in size . . . ya think ?? Something to compare to a bullet passing through a human body - avoiding all solid objects that would alter the trajectory.

I could be babbling, I haven't had breakfast yet :)

Alex Bravo
01-18-2007, 08:42 PM
I enjoyed all the discussions above.

Another fascinating topic is long run-out landslides. It is mind boogling to me that a tall mountain can fall and then its landslide run, sometimes uphill, almost 10 times its original height. When you think about it, it seems impossible, and yet they occur.

MidnightMuse
01-18-2007, 09:09 PM
I have a ton of questions regarding EMP blasts and the after effects.

You know, for when the conversation wanders that direction :)

PeeDee
01-18-2007, 09:11 PM
I have a ton of questions regarding EMP blasts and the after effects.

You know, for when the conversation wanders that direction :)

Feel free to wander it wherever you like. I'm enjoying this thread no end. I have this notebook that occasionally doubles as a mousepad which I scribble down topics on from this thread, and then I read them late in the evening (which is not the best time to comprehend Tesla theories or some such)

Landslides pick up momentum as they're sliding, and they pick up more debris, and the stuff at the back is pushing the stuff up front. I guess it makes sense that they can go a long, long way once they hit a flat surface. That's a lot of weight with a lot of momentum to bleed off.

veinglory
01-18-2007, 09:16 PM
Most of the Tunguska explanation are like Kennedy's magic bullet. They take a freaky thing and make it spuriously even more freaky. An asteroid strike seems to account for the known facts, landing in a great big swamp and not looking for a decade explains not finding and remaining parts of it...?

MidnightMuse
01-18-2007, 09:52 PM
Speaking to the issue of landslides - have you ever seen a documentary about Mount St Helens? I live here, and remember the whole thing, and yet when I saw this documentary just this past summer I was awe-struck by the devastation not only of the eruption itself, but the resulting mud flow and destruction caused as an entire forest and half a mountain pushed their way through a valley.

The power of the blast almost paled in comparison to the kinetic energy of the mud flow and the square-miles of destruction. You look at maps of the mountain pre-eruption and then compare that to the point -- miles and miles away - where the mud finally stopped progressing, and it's mind-boggling to say the least.

I remember seeing news broadcasts of some mudslides in California recently where two guys were running away from a pile of mud and debris coming toward them, over a flat surface (not downhill) and I almost couldn't believe this mud was not only still flowing toward them, but picking up speed.

AzBobby
01-18-2007, 10:34 PM
Most of the Tunguska explanation are like Kennedy's magic bullet. They take a freaky thing and make it spuriously even more freaky. An asteroid strike seems to account for the known facts, landing in a great big swamp and not looking for a decade explains not finding and remaining parts of it...?

Naw, an equally unfreaky explanation is that the thing vaporized before landing, blasting the forest with its shockwave but leaving no crater. They've studied the area enough by now not to have missed a great big swamp o' meteorite. Interestingly, it's hard for them to even find the impact pattern where the forest had been flattened. It exists, but you can't see it in the satellite photos anymore. There was a cool doco on one of the science channels about them studying the butterfly pattern of destruction, which mimicked some nuclear testing sites. From the pattern, they figured out the exact angle at which the thing hit the atmosphere and estimated its final distance above ground zero.

When I learned about it in childhood, the commonly supposed explanation was that an ice comet landed in Siberia. For various reasons above my head, the majority of scientists who forego explanations like black holes or mad Tesla experiments have leaned toward the asteroid explanation in recent decades, just to explain it having enough density to make it so close to the earth rather than blowing up much higher. Then there's some who step up and say "But wait, it's a floor polish and a dessert topping!" with the suggestion that some comets have plenty of rock in the mantle along with ice, and vice versa for some asteroids. Anyway, it's possible for such a huge thing to vaporize in a massive explosion without leaving solid pieces behind, without any real need for farout explanations like black holes passing through the earth.

When I refer to the great luck of it landing in Siberia, by the way, I'm aware of how sparsely populated the earth really is. But most of the earth's surface -- water -- doesn't count, because of the aforementioned tsunamis connecting us to great events within the oceans. Even the earth's most brutal deserts tend to be right next door to some major city, sometimes several, that would have been covered with the debris cloud and experienced some of the shock wave. Other than Antarctica, it's hard to think of land areas as massive as northern Asia with similarly sparse populations. I'm not sure how the northern regions of Canada compare. There may be a long list of "safe" impact points for all I know, but I have the strong impression that there's a much longer list of unsafe ones.

Still, while no one was killed by Tunguska, I can't help but sympathize with the nearby natives who were blown off their feet and looked up to see flames shooting through the morning sky and the tops of trees flying off. It was not silly of them to believe the world was coming to an end.

AzBobby
01-18-2007, 10:44 PM
Oh, and did someone mention EMPs??

I'd never known about it until, as a youngin', I read The Dark Knight Returns by Frank Miller. In it, the electromagnetic pulse from a nuclear blast causes massive blackouts and knocks planes from the sky. There's quite a bit to read about EMP devices that don't require nuclear blasts. Now there's a WMD that sounds frightening to me.

PeeDee
01-18-2007, 10:55 PM
Oh, and did someone mention EMPs??

I'd never known about it until, as a youngin', I read The Dark Knight Returns by Frank Miller. In it, the electromagnetic pulse from a nuclear blast causes massive blackouts and knocks planes from the sky. There's quite a bit to read about EMP devices that don't require nuclear blasts. Now there's a WMD that sounds frightening to me.

HAH!

That's where I first read about EMP's too.... :D

MidnightMuse
01-18-2007, 11:05 PM
A most fascinating article on the realities/weapons potential of EMPs:

http://www.airpower.maxwell.af.mil/airchronicles/kopp/apjemp.html

But it seems to me, realistically, the only country this weapon would truly harm would be - Us. The reach of these waves in weapon form is very limited, and even a nuclear blast's emp wave seems to be limited in square mileage - but I can't quite figure out how much.

I'm still reading this article - it takes some digesting.

And it leads me into a whole 'nother topic more suited for a thread of its own one day, regarding the implications and theories of recovery/methods of surviving if this country were ever attacked on a major- multi-state scale. Impacts on individuals, on towns, on the country as a whole - society in general, etc etc.

PeeDee
01-18-2007, 11:11 PM
Oooooh....start thread, Muse. Let's logically work out what would happen and how we would survive (we meaning us people) after a major attack.

Pthom
01-19-2007, 12:30 AM
Note: This post is in response to one that remains in this (http://absolutewrite.com/forums/showthread.php?t=50500)thread. Please refer to it for continuity.
----------------------------------------------------------------------------------

... It's also not a shield volcano. Those are the relatively flat kind found in Hawaii and their eruptions aren't violent at all, essentially just rivers of lava. Yellowstone is a supervolcano; the largest of its kind on earth. If it erupts (and geologists believe that it is overdue to do so) then this entire continent will become unliveable for a unknown (to me) number of years and the ash from the eruption will block out the sun for at least a year. Hundreds of millions worldwide will die of starvation. The human race has survived the eruption of a supervolcano before, but life after one will still be hell for decades afterwards. ...The error is mine. Yellowstone is a caldera (http://vulcan.wr.usgs.gov/Glossary/VolcanoTypes/volcano_types.html), but it is still the result of a hot spot that is responsible for most of the volcanism between Astoria, Oregon, and the current location of Yellowstone National Park.

MidnightMuse
01-19-2007, 12:33 AM
Thread titled Aftermath practicalities - FTI (for those interested)

a tree of night
01-19-2007, 12:52 AM
For various reasons above my head, the majority of scientists who forego explanations like black holes...

If (let me repeat that IF) Bekenstein and Hawking are correct, a small black hole would have evaporated and emitted a bunch of radiation in the process.

Pthom
01-19-2007, 12:53 AM
I moved some posts here (beginning with #54 above) from the thread on Researching Fantasy (whatever it's called)...mainly because the contents have nothing to do with the original topic. (The moved threads deal with volcanos, mostly.)

Some of you made responses to those posts, however, that I left in the other thread, because THOSE did contain pertinent responses. Tanatra, yours especially. If you like, would you continue with your intrest in geology here?

Thanks everyone.

AzBobby
01-19-2007, 01:10 AM
If (let me repeat that IF) Bekenstein and Hawking are correct, a small black hole would have evaporated and emitted a bunch of radiation in the process.

This is fascinating and also above my head. I don't rule out anything freakish, knowing no better. However, I think studies of the area and its people have revealed no evidence of unusual radiation effects, ruling out, for example, the theory of a hydrogen bomb going off a few decades ahead of its time. Some natives did blame illnesses on the event -- boils and whatnot that could be confused for the kind of ailments suffered after Hiroshoma -- but these seem to be explained by a coincidental small pox epidemic not long afterward.

Vincent
01-19-2007, 03:00 AM
Here's an old sci-fi favorite of mine. The rail gun.


A missile punch at bullet prices

Dahlgren demonstrates electromagnetic rail gun

Date published: 1/17/2007

By MICHAEL ZITZ

Normally, new weaponry tends to make defense more expensive. But the Navy likes to say its new railgun delivers the punch of a missile at bullet prices.

A demonstration of the futuristic and comparatively inexpensive weapon yesterday at the Naval Surface Warfare Center at Dahlgren had Navy brass smiling.

The weapon, which was successfully tested in October at the King George County base, fires nonexplosive projectiles at incredible speeds, using electricity rather than gun powder.

The technology could increase the striking range of U.S. Navy ships more than tenfold by the year 2020.

"It's pretty amazing capability, and it went off without a hitch," said Capt. Joseph McGettigan, commander of NSWC Dahlgren Division.

"The biggest thing is it's real--not just something on the drawing board," he said.

The railgun works by sending electric current along parallel rails, creating an electromagnetic force so powerful it can fire a projectile at tremendous speed.

Because the gun uses electricity and not gunpowder to fire projectiles, it's safer, eliminating the possibility of explosions on ships and vehicles equipped with it.

Instead, a powerful pulse generator is used.

The prototype fired at Dahlgren is only an 8-megajoule electromagnetic device, but the one to be used on Navy ships will generate a massive 64 megajoules. Current Navy guns generate about 9 megajoules of muzzle energy.

The railgun's 200 to 250 nautical-mile range will allow Navy ships to strike deep in enemy territory while staying out of reach of hostile forces.

Rear Adm. William E. "Bill" Landay, chief of Naval Research, said Navy railgun progress from the drawing board to reality has been rapid.

"A year ago, this was [just] a good idea we all wanted to pursue," he said.

Elizabeth D'Andrea of the Office of Naval Research said a 32-megajoule lab gun will be delivered to Dahlgren in June.

Charles Garnett, project director, called the projectile fired by the railgun "a supersonic bullet," and the weapon itself is "a very simple device."

He compared the process to charging up a battery on the flash of a digital camera, then pushing the button and "dumping that charge," producing a magnetic field that drives the metal-cased ordnance instead of gun powder.

The projectile fired yesterday weighed only 3.2 kilograms and had no warhead. Future railgun ordnance won't be large and heavy, either, but will deliver the punch of a Tomahawk cruise missile because of the immense speed of the projectile at impact.

Garnett compared that force to hitting a target with a Ford Taurus at 380 mph. "It will take out a building," he said. Warheads aren't needed because of the massive force of impact.

The range for 5-inch guns now on Navy ships is less than 15 nautical miles, Garnett said.

He said the railgun will extend that range to more than 200 nautical miles and strike a target that far away in six minutes. A Tomahawk missile covers that same distance in eight minutes.

The Navy isn't estimating a price tag at this point, with actual use still about 13 years away. But it does know it will be a comparatively cheap weapon to use.

"A Tomahawk is about a million dollars a shot," McGettigan said. "One of these things is pretty inexpensive compared to that."

He said estimates today are that railgun projectiles will cost less than $1,000 each, "but it's going to depend on the electronics."

Projectiles will probably eventually have fins for GPS control and navigation.

To achieve that kind of control and minimize collateral damage, railgun ordnance will require electronic innards that can survive tremendous stress coming out of the muzzle.

"When this thing leaves, it's [under] hundreds of thousands of g 's, and the electronics of today won't survive that," he said. "We need to develop something that will survive that many g 's."

At the peak of its ballistic trajectory, the projectile will reach an altitude of 500,000 feet, or about 95 miles, actually exiting the Earth's atmosphere.

The railgun will save precious minutes in providing support for U.S. Army and Marine Corps forces on the ground under fire from the enemy.

"The big difference is that with a Tomahawk, planning a mission takes a certain period of time," McGettigan said. "With this, you get GPS coordinates, put that into the system and the response to target is much quicker from call to fire to actual impact."

General Atomics, a San Diego defense contractor, was awarded a $10 million contract for the project last spring.

The concept was born in the 1970s then promoted when President Ronald Reagan proposed the anti-missile "Star Wars" Strategic Defense Initiative. The SDI railgun was originally intended to use super high-velocity projectiles to shoot down incoming ballistic missiles.


http://fredericksburg.com/News/FLS/2007/012007/01172007/251373

blacbird
01-19-2007, 03:35 AM
A question, that maybe someone will know the answer to around here:



Why is that? Thus far, all I have seen seem to indicate that the deeper you get, the softer-bodied the creatures get. Wouldn't it be logical to assume that you would need a harder and more durable exo-skeleton to survive the intense PSI down that deep....?
[/size]

The major reason any organism can survive extreme pressures is that their internal pressure is equalized to the external pressure. Since they don't contain any gaseous parts, that's actually pretty easy. We'd get squashed because we need gas in our lungs, and that wouldn't sustain the external pressure.

The major reason "shelly" creatures don't exist at these extreme dephts is actually chemical. Cold water at pressures greater than a certain amount will not hold CO2 in solution. And that's what carbonate-secreting organisms need to build CaCO3 exoskeletons. Below a certain depth, called the carbonate-compensation depth, there simply is no raw material for carbonate secretion.

Some fish can and do live at these most extreme depths. Vertebrate skeletons, which are internal, are made of calcium phosphate, not calcium carbonate. The phosphate ion can remain in solution at these extreme depths, so is available for creatures that need it.

caw

blacbird
01-19-2007, 03:42 AM
Regards the Tunguska event: For quite some time it was thought that it might have been a small comet, made primarily of ice, rather than a meteorite/asteroid, that exploded high enough in the atmosphere not to leave a surface crater. Quite recently we have learned that some, perhaps most, asteroids are rather "fluffy", loosely consolidated piles of stuff rather than indurated single pieces. This might also explain the characteristics of that explosion.

It's just a damgood thing it happened over one of the least-populated land areas of the planet, rather than, say, over someplace in western Europe, or eastern China, or the eastern U.S.

Which brings up another matter: 3/4 of the earth's surface is ocean. So the chances are 3 in 4 of such a strike happening over water than over land. Ya gotta wonder how often in earth's history that happens.

caw

Peggy
01-19-2007, 03:58 AM
The major reason "shelly" creatures don't exist at these extreme dephts is actually chemical. Cold water at pressures greater than a certain amount will not hold CO2 in solution. And that's what carbonate-secreting organisms need to build CaCO3 exoskeletons. Below a certain depth, called the carbonate-compensation depth, there simply is no raw material for carbonate secretion. Interesting. Does that mean that "shelly" creatures could develop their shells in lower pressure zones and then feed in deeper waters? Or do the shells require constant renewal?

blacbird
01-19-2007, 05:42 AM
Interesting. Does that mean that "shelly" creatures could develop their shells in lower pressure zones and then feed in deeper waters? Or do the shells require constant renewal?

No. Calcium carbonate dissolves below the carbonate compensation depth.

Which brings up a mea culpa. In my first post I had it backwards. Carbon dioxide remains in solution at depth, but CaCO3, which the shelly organisms (clams, snails, corals, etc.) make from it is, as I say above, what dissolves at depth. Sorry. Brain cramp while eating lunch is my excuse.

Addtionally, some microscopic organisms, like diatoms, make silica (SiO2) for skeletal structures, but that mineral (quartz, essentially) is too brittle to work as a skeletal framework for larger organisms. It is, however, stable at depth, and most of the really deep parts of the ocean floor are covered with silica ooze as a result of the remains of these creatures.

caw

MidnightMuse
01-19-2007, 08:32 AM
No. Calcium carbonate dissolves below the carbonate compensation depth.
....that mineral (quartz, essentially) is too brittle to work as a skeletal framework for larger organisms. It is, however, stable at depth, and most of the really deep parts of the ocean floor are covered with silica ooze as a result of the remains of these creatures.

caw

I'm impressed ! And fascinated. I thought it was simply a matter of psi and gas - coupled with the lack of flexibility a skeletal structure would have. I need to watch Discovery a little more often.

Pthom
01-19-2007, 08:43 AM
Wait.

Isn't psi and gas a function of psychics who eat too many beans?

PeeDee
01-19-2007, 08:43 AM
I'm impressed ! And fascinated. I thought it was simply a matter of psi and gas - coupled with the lack of flexibility a skeletal structure would have. I need to watch Discovery a little more often.

Same here. I didn't realize anything that blacbird just posted, and it fascinates. It never even occured to me that a hard body would be built of things that are not necessarily present or stable at all depths and points on the earth.

MidnightMuse
01-19-2007, 07:26 PM
Wait.

Isn't psi and gas a function of psychics who eat too many beans?

Yes, of course, you're right - my bad :D

PeeDee
01-23-2007, 05:54 AM
I guess it was high time for a fart joke to penetrate this thread, huh? :)

Pthom
01-23-2007, 01:35 PM
I suppose we could discuss the ... no, maybe not.

Um. How many human beings are necessary to perpuate the species? Say there was a major disaster and only a few of us survive.

PeeDee
01-23-2007, 07:32 PM
I suppose we could discuss the ... no, maybe not.

Um. How many human beings are necessary to perpuate the species? Say there was a major disaster and only a few of us survive.

More than two, certainly. But you'll need someone wiser than me to answer, I suspect. Six?

MidnightMuse
01-23-2007, 07:43 PM
That would require a bit of thinking genetics-wise. We'd have to figure out the gene pool strength and how many toes we want our future humans to have.

Oh, and I volunteer not to contribute any genes :D Guess that means I'll be tossed outta the lifeboat, eh?

Dang.

PeeDee
01-23-2007, 07:50 PM
That would require a bit of thinking genetics-wise. We'd have to figure out the gene pool strength and how many toes we want our future humans to have.


Yeah, what side of town would these people be coming from? Do they listen to country music? :)

Peggy
01-24-2007, 02:21 AM
Um. How many human beings are necessary to perpuate the species? Say there was a major disaster and only a few of us survive.
That question is actually very important to people interested in saving species on the verge of going extinct - the term you need to look for is Minimum Viable Population (MVP).

http://en.wikipedia.org/wiki/Minimum_Viable_Population
http://www.nwfsc.noaa.gov/publications/techmemos/tm198/
http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=121997

I believe the generally-accepted MVP for mammals is on the order of thousands of individuals. Of course the calculations assume random mating, so it's possible that the MVP for humans could be smaller, if the remaining human population was able to determine optimal mating pairs (and the individuals involved went along with it). If you are feeling up to a more heated discussion, you could go back to the old evolution-creationism thread, where the issue of whether the human race could have descended from a single breeding pair is discussed in detail.

AzBobby
01-24-2007, 04:56 AM
Neat topic. Like Pete I'd guess six as a rough minimum to give the species hope, meaning that you could have three generations who aren't cross bred, with the third having to pair up with second cousins to carry on. That doesn't sound attractive, but it sounds survivable to my inexpert mind (regardless of your stance on Genesis, I'm recalling how DNA experts trace the whole surviving race to one fully evolved human mother in ancient Africa).

For the minimum "attractive" alternative I'd borrow someone's idea from 30 Rock the other night where a couple accidentally found out they were cousins and the guy said he could live with it if they were at least fifth cousins. In that case you'd have to start out with... um... 12 people, that is, six unrelated couples? --If my tired brain has considered the numbers correctly.

It gets more interesting when clinical theories are applied that don't match our cultural norms. Pete's suggestion falls down if the couples are Catholic, for example. Then at least one of the six has to be a priest to properly marry the other two possible couples, and their kids are stuck marrying first cousins. :) Others might argue that the couples, regardless of whether there be three or twenty of them, should swing as much as possible to maximize gene variation, chances of procreation, etc. And then there are other directions of argument to take that might challenge the balance of males to females, perhaps having polygamist strategies mapped to correspond to scientific data suggesting maximum chances of reproduction, gene diversity, and so on. More environmentally specific plans can take food supply and housing into consideration.

There are some fun stories where the moral norms that are agreeable to most of us are tossed out because the human race has to start over. I think the most recent one I read was Vonnegut's Galapagos.

benbradley
01-24-2007, 06:15 AM
There are some fun stories where the moral norms that are agreeable to most of us are tossed out because the human race has to start over. I think the most recent one I read was Vonnegut's Galapagos.

I recall a story in Asimov's or somewhere, about sending a one-way ship to the stars to repopulate humanity, perhaps the Sun was going to go Nova and this was the only hope for humanity. It had two dozen people on board, and the story was titled "The Twenty And The Four."

Pthom
01-24-2007, 10:35 AM
Peggy's links are interesting but aren't very helpful. The articles acknowledge that there is a problem with genetic viability, but don't supply conclusions. I think three generations isn't remote enough to ensure enough diversity in the species to prevent things like racial idiocy. There are plenty enough stories of how some royal families suffered from this because of inbreeding. And it happens all the time in domesticated animals, especially pets.

My supposition is that given a closed environment such as a generation ship, you would need several thousand individuals to maintain a viable population for the time it would take to reach another star. I discount such bolognial ideas as faster-than-light travel, teleportation, etc.

Perhaps animals descended from a dozen pairs would perpetuate the species, but at what cost?

Peggy
01-24-2007, 01:08 PM
There are some fun stories where the moral norms that are agreeable to most of us are tossed out because the human race has to start over. I think the most recent one I read was Vonnegut's Galapagos.I haven't read Galapagos, so I don't know how Vonnegut approached the problem, but one way a small human population might survive is by completely separating reproduction from love and marriage. That way "matings" could be arranged for optimal genetics without requiring people to form life-long partnerships with people they are not attracted to (or even like). It probably also would be good to mix it up as much as possilble.

Like Pete I'd guess six as a rough minimum to give the species hope, meaning that you could have three generations who aren't cross bred, with the third having to pair up with second cousins to carry on. It is partially going to depend on how related those surviving individuals are to each other. If they are very unrelated (one from Asia, one from Africa, one from South America, etc.) there is a much better chance of species survival than if the remaining humans are all from the same small town where people have been intermarrying for many generations.
That doesn't sound attractive, but it sounds survivable to my inexpert mind (regardless of your stance on Genesis, I'm recalling how DNA experts trace the whole surviving race to one fully evolved human mother in ancient Africa). Actually "mitochondrial Eve (http://en.wikipedia.org/wiki/Mitochondrial_Eve)" is the most recent common female ancestor of humans, and is estimated to have lived 150,000 years ago.
A common misconception is that Mitochondrial Eve was the only living human female of her time she was not. Had she been the only living female of her time, humanity would most likely have become extinct (http://en.wikipedia.org/wiki/Extinct) due to the extreme population bottleneck (http://en.wikipedia.org/wiki/Population_bottleneck). Many women alive at the same time as Mitochondrial Eve have descendants alive today. Some of those women may even be ancestors to all humans alive today while others may be ancestors to only some of the humans alive today. However, only Mitochondrial Eve, and her matrilineal ancestors, have a pure matrilineal (http://en.wikipedia.org/wiki/Matrilineal) line of descent to all humans alive today. Because mitochondrial DNA is only passed through matrilineal descent, all humans alive today have mitochondrial DNA that is traceable back to Mitochondrial Eve. The analysis only included DNA from the mitochondria (an organelle in the cell), not nuclear DNA (commonly called "genomic DNA"). The male equivalent "Y-chromosomal Adam (http://en.wikipedia.org/wiki/Y-chromosomal_Adam)", likely lived 60,000-90,000 years ago. There is a decent explanation here (http://www.talkorigins.org/faqs/homs/mitoeve.html).

MidnightMuse
01-24-2007, 07:42 PM
If you were going to PLAN this repopulation idea, say you're sending a group out on a ship to another world (or something) then you'd want to take many factors into consideration to insure their survival - not only giving them a deep gene pool to swim in, but also insuring there were as few mutations as possible.

You'd have to weed out damaged chromosomes to avoid as many inheritable disorders as possible, and that alone is going to narrow your available pool.

Which is a different problem than if the world we live on had something occur, leaving only a handful left to re-fill it. In that case, it wouldn't matter who was left, they'd have to make-do.

Dang, I've forgotten at least half the genetics stuff I learned in school - I wonder what my brain needed the room for?

PeeDee
01-24-2007, 10:36 PM
It gets more interesting when clinical theories are applied that don't match our cultural norms. Pete's suggestion falls down if the couples are Catholic, for example. Then at least one of the six has to be a priest to properly marry the other two possible couples, and their kids are stuck marrying first cousins. :) Others might argue that the couples, regardless of whether there be three or twenty of them, should swing as much as possible to maximize gene variation, chances of procreation,
.

Interestingly enough, I was thinking about exactly that, because in A Canticle For Leibowitz (which is the greatest apocolypse books ever) they sent priests away on the colony ship, but they also had to send Bishops to ordaine the priests and I believe a couple of Cardinals and pontiffs from Rome, so that the succession of the Pope could continue unabated. It was very interesting.

In fact, I think we could do an interesting thread (or hijack this thread) on firstly, how a colony ship would logically work out and who would be on it and secondly, how either a colony ship or a survivor group on Earth would work with the influence of the Catholic church.

AzBobby
01-24-2007, 10:54 PM
The story of "mitochondrial Eve" is interesting stuff too. I wasn't suggesting she was alone or was the first human. On the contrary, it just sounds like the race survived from a population sample comparable to a bottleneck after the human race had already evolved to some large number unknown. That is, our African ancestor likely belonged to a community, and who knows how many husbands she could have had, and cousins and so on with whom she lived. But if she had been the only one alive with only a few males around (the specific male or males with whom she alone mated), it seems, it remained possible to save the whole species assuming her little group kept themselves fed and safe. This acknowledges our common ancestry with that group of males too and their ancestors, but this "Eve" story (badly named as it may be) still seems to indicate that her limited family led to the rest of us billions, regardless of how many other humans were on the earth at the same time as her. Or am I getting something wrong here?

The Galapagos scenario, by the way, places the surviving humans on an island while the rest of the world passes on. I won't spoil how it goes, but Vonnegut approaches the details in typically whimsical fashion.

The reference to "The Twenty and the Four" (which I'll have to dig up and read now) reminded me of another human survival theme, of how cultural and moral norms are speculated to change in the age of space travel. Being a fan of C.S. Lewis, I fondly recall an sf story of his that satirized that trend -- "Ministering Angels" I think. It wasn't about the rest of the human race dying out, but it was a skewed response to the notion that we'd need to plan on delivering pretty girls to space colonies to fill the needs of the lonely astronauts there. His take on the subject was based on the question -- what kind of women would be the ones who would go along with such a creepy idea?

How might we apply similar questions to clinical approaches to extending the human race? For example, if all the moral/cultural norms we favor by popular approval are tossed aside in the process, what kinds of people are most likely to survive, and how will the resulting earth population vary from the one we know?

I'm tempted to presume some sort of dystopian result, but then I'm reminded of Australia...

Pthom
01-24-2007, 11:16 PM
Okay, I am duly impressed with the information arising from this latest part of the thread. Following the wikipedia link in Peggy's last post, I discovered this:

Population Bottlenecks and Volcanic Winter (http://www.jqjacobs.net/anthro/paleo/bottleneck.html)
At least, this validates my supposition that a mammalian species can survive with as few as 1000 individuals.

But let's hope we don't have to find out whether this is indeed true any time soon.

Higgins
01-25-2007, 12:09 AM
More than two, certainly. But you'll need someone wiser than me to answer, I suspect. Six?

Long ago we were taught that a population needed to be at least 10,000 to avoid a chance that random genetic drift could catastrophically erode useful genes and substitute worthless (ie non-adaptive) ones because of the statistics of
recombination.

If you controlled the breeding you might get away with less than 10,000.

If you had perfectly adapted clones, you could have as few as you wanted...unless they started breeding (at the usual Hardy-Weinberg equal chances for all genes level, which oddly enough is what happens when people reproduce freeely) "normally" (at the usually HArdy-Weinberg etc.).

MidnightMuse
01-25-2007, 12:15 AM
In fact, I think we could do an interesting thread (or hijack this thread) on firstly, how a colony ship would logically work out and who would be on it and secondly, how either a colony ship or a survivor group on Earth would work with the influence of the Catholic church.

I can't speak for the Catholic church influence, being not-Catholic myself, but a seperate thread exploring the possibilities of this would be fun.

PeeDee
01-25-2007, 12:44 AM
I can't speak for the Catholic church influence, being not-Catholic myself, but a seperate thread exploring the possibilities of this would be fun.

I am....hesitant to start what's basically another scientific thought thread. I don't want to take over the SF/F forum and fill it up with logic and science... :)

PeeDee
01-25-2007, 12:47 AM
Long ago we were taught that a population needed to be at least 10,000 to avoid a chance that random genetic drift could catastrophically erode useful genes and substitute worthless (ie non-adaptive) ones because of the statistics of
recombination.

If you controlled the breeding you might get away with less than 10,000.

If you had perfectly adapted clones, you could have as few as you wanted...unless they started breeding (at the usual Hardy-Weinberg equal chances for all genes level, which oddly enough is what happens when people reproduce freeely) "normally" (at the usually HArdy-Weinberg etc.).

I think you could get away with a lot less than 10,000.

Humpback whales, for example, which are just now beginning to build their population back up, were under 10,000 for example.

While human genes may be more complex than whale genes -- and therefore, the introduction of non-adaptive genes might degrade humans into a less than sentient and civilized state -- I think that the species as a species could survive on a much, much smaller number.

However, I think that the 10,000 number is accurate if you wanted to continue the species and additionally maintain some semblence of human culture. If not human culture, then human consciousness and sentience. If you see what I mean.

RTH
01-25-2007, 12:56 AM
Hey, I knew this grad-school stuff would come in handy some time!

Generally speaking, since humans are extremely slow reproducers (as are chimps, gorillas, & orangs), they'd need a larger population (than say, rats would) to be minimally viable. Though the more genetically diverse that population, the fewer people you could get away with before you start getting founder effect.

However, that being said, small founder populations are a great way to generate lots of evolutionary change very quickly, as you'll end up with recessive gene expression a lot more often. It's a good way to form new species in a short amount of time.

Our species appears to have gone through a genetic "bottleneck" event in the last 100-150,000 years -- a sudden dropoff in population and a new growth started by that reduced founder group (most likely in Africa). With all our geographic variation and soon-to-be 7 billion people, we have far less genetic variation than the measley few thousand chimpanzees left around today...

Which is one reason why we say there's no such thing as biological "races" of people. For all intents and purposes, we're pretty much genetically identical.

Higgins
01-25-2007, 01:28 AM
I think you could get away with a lot less than 10,000.

Humpback whales, for example, which are just now beginning to build their population back up, were under 10,000 for example.

While human genes may be more complex than whale genes -- and therefore, the introduction of non-adaptive genes might degrade humans into a less than sentient and civilized state -- I think that the species as a species could survive on a much, much smaller number.

However, I think that the 10,000 number is accurate if you wanted to continue the species and additionally maintain some semblence of human culture. If not human culture, then human consciousness and sentience. If you see what I mean.

If you want to count on being really lucky all the time you could pick a founder population of any size...the smaller it is, they luckier you have to be.

Apparently our species was very lucky the last time we went through a bottleneck.

blacbird
01-25-2007, 02:23 AM
There is evidence that Homo sapiens was reduced in number to no more than a few thousand individuals, owing to some bad event, around 75,000 years ago. All modern humans have descended from that small population, according to DNA analyses (which I don't pretend to understand). Apparently human variation in DNA is extremely narrow, indicative of a limited pool of population in the past.

This timing accords closely with the last known eruption of a mega-volcano, what is now the Toba Caldera in central Sumatra, about 74,000 years ago. Some scientists have suggested that as the culprit. It would have messed up the earth's environment big-time for some years afterward.

And, just for grins, remember that Yellowstone is an even bigger volcano, the largest, most powerful known on the planet.

caw

AzBobby
01-25-2007, 03:52 AM
Being a Phoenix native, I learned in childhood that at one time a few decades ago, our zoo saved the Arabian Oryx from extinction. That is, there was a point where the only herd left on earth was in Phoenix. There were exactly seven of these large animals. Meanwhile, the species was hunted to extinction in the wild in their native middle east. Now there are hundreds scattered around the world, all seeded from those seven from Phoenix, but I think most of them are still members of herds raised in zoos.

As they increase in number, slowly but surely, should we believe there's still a lot of luck required for their genes to keep the species going for a long haul? I confess I don't know much about the genetics crap shoot that constantly goes on during natural selection. But comparing this to stories such as the failed effort to keep some Tasmanian tigers in captivity in the early 20th century (although I read they did a lousy job of it) it seems to come down to adaptability. Obviously, the oryx feel just fine about being raised in captivity. Lucky oryx. Animals like some of the endangered whales and tigers and such don't have that particular luck bred into their personalities.

If the human race must be seeded with a small number of individuals, even seven, can our viability really be compared to that of panda bears and the like? With the luck required to duck natural disasters for a few decades, might our adaptability -- especially if we retain modern medicines and some helpful technology -- be considered somewhat higher than a number of these comparisons?

PeeDee
01-25-2007, 03:58 AM
One thing is that I bet with the careful reseeding of the Oryx population (I remember reading about that; it made me happy), this was being monitored and studied by human scientists who knew more about genetics than we do (certainly more than I do). That makes a difference. Not a huge difference.

I think that with seven individuals or so, humanity could continue and propser without any major physical defects appearing.

I do, however, wonder if our more civilized traits would eventually be bred or evolved out of us? If the species began again from only seven Oryx, it doesn't matter if reasoning and the other unique traits of a human being are bred out. They are limited anyway. WOULD we survive physically, but degrade mentally?

dclary
01-25-2007, 04:05 AM
caltech scientists announced they had a memory circuit that could store the equivalent of the declaration of indepence upon.

It's the size of a white blood cell.

They expect they could build a structure of them that would store 100 gigabits (about 12.5 gigabytes?) per *centimeter.* They think Intel could have them in laptops by 2020.

PeeDee
01-25-2007, 04:11 AM
caltech scientists announced they had a memory circuit that could store the equivalent of the declaration of indepence upon.

It's the size of a white blood cell.

They expect they could build a structure of them that would store 100 gigabits (about 12.5 gigabytes?) per *centimeter.* They think Intel could have them in laptops by 2020.

*is very quiet for a moment or two*

So...in theory...whoa.

Whoa.

The little writerly bit in the back of my mind just triggered into overdrive.

Rolling Thunder
01-25-2007, 04:16 AM
All it needs now is an OS that doesn't suck like Windows.

PeeDee
01-25-2007, 04:19 AM
And like a bad date, you scare off the serious bit of my writerly mind.

(It's still there. It's chewing on a great short story alluva sudden.)

Rolling Thunder
01-25-2007, 04:27 AM
And like a bad date, you scare off the serious bit of my writerly mind.

(It's still there. It's chewing on a great short story alluva sudden.)

Actually, I was being quite serious. Microsoft is all about retaining market share. Back when MS-Dos was the big gun OS it still had limits and was more like trying to carry ten pounds of snot in a five pound head.

PeeDee
01-25-2007, 04:30 AM
A memory card (or, in this case, sliver) doesn't need an OS though, so it wouldnt' be a problem. I hope.

There was a Star Trek episode in which they tried to transfer people's consciousnesses into android bodies, imrinting their thought patterns onto circuitry. This sounds worryingly like that. Or could be used to sound worryingly like that.

Rolling Thunder
01-25-2007, 04:39 AM
Well, I haven't kept up with PC technology like I used to. I know at one time motherboards could only process a certain amount of information which led to cache RAM and shadow RAM and other techniques to speed things up.

Heck, even Bill Gates never envisioned much more than 16 bit processors and didn't see the need for improving MSDOS until technology kicked him in the rear.

PeeDee
01-25-2007, 04:42 AM
They can still only process so much at once. We haev a billion different kinds of RAM now. But a memory chip/sliver only has to hold information. It doesn'te ven have to define what it is (the memory card doesn't need to know what a .jpg is, the computer will recognize it).

Pthom
01-25-2007, 02:07 PM
I am....hesitant to start what's basically another scientific thought thread. I don't want to take over the SF/F forum and fill it up with logic and science... Would you guys like a sub forum so you can have separate threads for each topic?

Or do you like the way this thing rambles about, touching on one subject here, another there, randomly?

I kinda like the latter (the way it is), but it occurs that down the road, it's gonna be hellacious to look anything up.

Peter.

PS, I did ask Mac if she wanted a "Writing Science" forum--she declined. So it's one of the two options above.

PeeDee
01-25-2007, 06:27 PM
I'd like a sub-forum, because I love the way this thread rambles, but then it's fun to splinter off and talk about something else in a whole nother thread. There's no guarantee THIS thread stays on one topic long enough to fully work through it, before we shift. So new threads would be rising anyhoo.

MidnightMuse
01-25-2007, 07:31 PM
It is kinda dizzying the way this one can turn - not that it's a bad thing. I was gonna say something about this amazing video I saw this morning re: a Frilled Shark being found off the coast of Japan, and then go on about how little we know about our own planet still - but now I'm all caught up in the memory-cell-the-size-of-a-white-blood-cell idea !

Makes one go: Wow.

RTH
01-25-2007, 09:23 PM
[quote=PeeDee]
I think that with seven individuals or so, humanity could continue and propser without any major physical defects appearing.quote]

Probably not the case -- the Amish are subject to a number of genetic disorders brought about by their small founder population (certainly larger than 7) and their consistent tendency to avoid breeding with outside populations.

You may not end up with kids having 3 eyes, but there would definitely tend to be a lot more bad genetic combos.

PeeDee
01-25-2007, 09:31 PM
[quote=PeeDee]
I think that with seven individuals or so, humanity could continue and propser without any major physical defects appearing.quote]

Probably not the case -- the Amish are subject to a number of genetic disorders brought about by their small founder population (certainly larger than 7) and their consistent tendency to avoid breeding with outside populations.

You may not end up with kids having 3 eyes, but there would definitely tend to be a lot more bad genetic combos.

All right, and this can be assumed because the Amish do not consciously put any thought into genetics when they (cold word) breed. But what if the seven-or-more humans used to repopulate the species were carefully guided?

You would have Amish-sort of defects appear if this were a bombed out husk of Earth and people were just repopulatiing as best they could. But what if it's a very small number sent into space, for example? And therefore, carefully chosen and carefully planned out. THAT would make things work differently.

MidnightMuse
01-25-2007, 09:51 PM
Yes, that's where the interesting stuff would come into play - having the new population-builders planned. Especially if you had the entire current population to pick from, and let studies and scientists figure it all out because you were sending this little ship (or whathaveyou) off on purpose - how much diversity would be required, and how many individuals would be needed?

PeeDee
01-25-2007, 10:00 PM
Even when they repopulate animal species, it's a well-planned process by scientists who know what they're doing.

So, assuming this was just the remnants of humanity left on earth, breeding would be a very tricky thing indeed.

rugcat
01-25-2007, 10:39 PM
Even when they repopulate animal species, it's a well-planned process by scientists who know what they're doing.(Emphasis added)

Apparently you move in different circles than I do.

PeeDee
01-25-2007, 10:43 PM
For the purpose of this thread, I'm being optimistic. :)

RTH
01-26-2007, 12:25 AM
Well, you'd certainly want as much genetic variation in those seven people as possible, for starters. Which means you probably want a member of an indigenous population from every continent and from widely varying climatic conditions. Though one might also want to weight more heavily toward Africa in one's choosing, as (being the place our species originated from) it has more genetic variation than any other continent.

Peggy
01-26-2007, 12:32 AM
Well, you'd certainly want as much genetic variation in those seven people as possible, for starters. Which means you probably want a member of an indigenous population from every continent and from widely varying climatic conditions. Though one might also want to weight more heavily toward Africa in one's choosing, as (being the place our species originated from) it has more genetic variation than any other continent. That could be the basis of a great adventure novel - only a few people on each continent remain, they somehow get into contact with each other, and agree to meet somewhere in the middle (North Africa?). We could follow each groups' travails as they attempt to travel thousands of miles with little or no technology.

Alternatively, the survivors could all be residents of New York City.

PeeDee
01-26-2007, 12:36 AM
That could be the basis of a great adventure novel - only a few people on each continent remain, they somehow get into contact with each other, and agree to meet somewhere in the middle (North Africa?). We could follow each groups' travails as they attempt to travel thousands of miles with little or no technology.

Alternatively, the survivors could all be residents of New York City.

Well, if ten of us want to do 10,000 words each, we can do it. If it's New York, it would probably end disasterously, with a knifing. Particularly if they're from Queens.
:)

This would, of course, all depend on what happens to the earth. Are we talking a plague? Are we talking a meteor strike? The collapse of nations? Nuclear strike?

Nuclear fallout, for example, would make a disaster of the whole genetic game.

Pthom
01-26-2007, 12:40 AM
Alternatively, the survivors could all be residents of New York City.Given today's population of New York, it would be very likely to have members from every continent in your group. ;)

AzBobby
01-27-2007, 01:22 AM
That could be the basis of a great adventure novel - only a few people on each continent remain, they somehow get into contact with each other, and agree to meet somewhere in the middle (North Africa?). We could follow each groups' travails as they attempt to travel thousands of miles with little or no technology.

Stephen King's The Stand gets a lot of its steam from the post-apocalyptic road trip story. Some telepathic goings-on draw the survivors from great distances (all within the US, though) to form a new seed community in a somewhat central location. The travails of the separate parties along the way are pretty cool, such as highways and tunnels blocked with wrecked cars all over the place.

Something similar fills much of the storyline of the film 28 Days Later, complete with the wrecked cars clogging tunnels.

It's probably been done, but I'd like to see some even more adventurous travel by the survivors in a post-apocalypse story -- like trying to make it across the ocean, or having to fly a hot-air balloon made by hand from odds and ends. There'd be shades of Jules Verne but with the unique additions of the leftovers of superior technologies of the past affecting what could be done and what new problems would occur.

Peggy
01-27-2007, 01:44 AM
Given today's population of New York, it would be very likely to have members from every continent in your group. That's exactly what I was thinking. :)

It's probably been done, but I'd like to see some even more adventurous travel by the survivors in a post-apocalypse story -- like trying to make it across the ocean, or having to fly a hot-air balloon made by hand from odds and ends. There'd be shades of Jules Verne but with the unique additions of the leftovers of superior technologies of the past affecting what could be done and what new problems would occur. Now that would be cool, like Jules Verne meets Mad Max meets Waterworld. I'm actually visualizing it as a series of stories told from different points of view. Eventually, some of the various protagonists would run into each other.