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How do you destroy a planet?

benbradley

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Space ships, Death Stars, turbolasers and tractor beam projectors are fun, but far from factual. Please don't forget this particular sub-forum is for discussions of science facts, not speculations.

Thanks. :)
That's JUST what I was thinking of, and this only uses fifty year old (gasp!) technology.

Thinking of "natural amplification" of current technologies, blowing a nuclear bomb at the Yellowstone supervolcano should be enough to "get it started."

If you don't have access to nuclear bombs, perhaps a large enough mass moving fast enough hitting the right place on Yellowstone might do it. A Saturn 5 Moonshot would do it, just replace the Command and Lunar Module areas with as much mass as you can boost up there. Not sure if it really needs to to a Moon shot turnaround, but that might make it easier to aim it with midcourse corrections and have it coming straight down through the atmosphere at 25,000+ mph. It would be an interesting heat shield design to keep it from burning up on the way down.

Getting back to the original question, this could be done on the Moon with a mass driver, enough payloads (one payliad hitting may not be enough, but MANY payloads sent one after another at slightly different speeds and precise midcourse corrections could add up to a substantial mass hitting all at once) and appropriate steering technology, which a long-term Lunar installation would surely already have to be able to ship things back to Earth. The payload control devices may need modifying so they can't be controlled from Earth on the way down, as that would surely be a safety feature if the Lunar launcher "accidentally" lost control and they were going to hit in the wrong place

Maybe an oil drilling rig going deep enough might start it off, but I imagine you'd get the attention of Mr. "Ranger" before you can drill too far.

Oh, wait, he's from Jellystone.

But if you're on the Moon and have the money and connections (and secure communications to reduce the chance of others finding out what you're doing), you could pay to have a drilling company somehow sneak in and start drilling at a remote location within Yellowstone.
Have the sun die and let nature take its course.

It takes a while, but the planet will eventually be destroyed. Right along with the rest of the solar system.

Misa, who thinks big.
The sun can shine on, but with space technology, it would only take a 1-mil or less reflective or absorptive film to stop all sunlight shining on the Earth, out at the L1 orbit between the Earth and Sun. This would be at least 8,000 (or larger due to paralax and the sizes of the Earth and Sun) miles in diameter, which could add up in mass, but this is just a little technology, not any new science. We've already got the James Webb Telescope being developed to capture a large amount of (very low-level) radiation in a precision way. All we want to do is block more of it.

There's also some visceral fear about a solar eclipse, especially when it doesn't stop and the Moon is nowhere near the Sun in the sky...
I'd keep an eye on the news from CERN and see if they manage to make any baby black holes... if that becomes plausible, then I'd go with creating a temporary black hole in the center of the Earth.
I'd construct a black hole. Isn't the earth covered in teeny tiny ones already?

I'll go even farther and say that a tiny black hole (assumed to be created by smashing two atomic nuclei together at mind-blowing energy levels) is even too tiny to absorb a single proton.
...
So black holes -- at least subatomic ones -- are definitely out.
Also, those generated in accelerators have such low mass that they don't last long enough to absorb any other particles. They radiate away virtually instantly from Hawking radiation (as I understand, that radiation and its timing after the initial events is actually how they claim to have made a black hole). It's just not big enough to stick around, and particle accelerators don't have enough power to make them much bigger.


Hmm... crash the moon into the Earth? Even if it doesn't completely destroy the Earth, if you do it right you could probably destabilize its orbit and send it spiraling towards the Sun. In which case, it would probably explode into tiny fragments. Just like the movies.

The time scale you'd be looking at may not fit your bill. But then again, steering the moon into the Earth would probably kill just about anything alive in the first few hours. The remaining bacteria/cockroaches probably wouldn't have time to develop the technology needed to reverse the planet's doomed trajectory before being vaporized in a giant molten nuclear furnace that practically defines "overkill".
Depending on the energy you have to do it, driving the Moon into the Earth would take years, decades, or centuries or longer. Perhaps long enough for lots of people on Earth to escape, even with a few "Noah's Arks" of other life on Earth.

The Moon wouldn't even have to hit, just get the orbit below the Roche Limit of either body. Either one breaking up would cause the destruction of at least the surface of the other.
Okay then a cut holes with drills such as they use in oil rigs in strategic positions around the planet, such as fault lines, to the core as close as you can get, and place bombs that are 10 times stronger than Little Boy in them. Explode the bombs at the same time and that should cause a tectonic plate reaction that would possibly destroy the planet.
They probably got 'em 100 to 1,000 times Little Boy, but getting them into a borehole might be a problem, though that's an interesting possibility.
Like I said, you would have to scale this up a bit, but the science is basically sound. All solids (I believe for our purposes, you can consider the crust to be solid) have a natural structural resonance frequency. If you find out what the Earth's NSRF is, you could theoretically build a device that causes a sympathetic vibration.
At first thought that sounds interesting and almost plausible Resonant frequencies of the Earth are already well known due to thousands of seismometers around the Earth, measuring every earthquake large enough to be detected. Here's a graph of the big earthquake in Japan A February 2010 Earthquake in Chile. The vertical scale is degrees from the earthquake (180 degrees is the opposite site of the Earth), and the horizontal is time in minutes. There's a minor echo at 90 minutes, and larger one at 180 minutes (this is a large file and takes a while to load):
http://www.unavco.org/community_science/science_highlights/2010/M8.8-Chile_RC_2010_8.8.pdf

The big earthquakes like the recent in Japan are already in the power range of the largest nuclear weapons, if not moreso. You should certainly be able to trigger some faults and/or supervolcanos with nuclear weapons causing great havoc on the surface virtually worldwide, but as far as making the whole Earth come apart, I don't believe it.
 
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Astronomer

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My understanding is that an eruption at Yellowstone would destroy at most just the civilized world on the North American continent. The lingering ash cloud, however, would certainly make life tough worldwide, but probably not unrecoverably so.

On the scale we're talking about, I think Earth's crust may as well be a liquid. Maybe more like a thin slice of processed cheese, but not really a solid. In fact, if you were to shrink Earth down to the size of an apple, Earth's crust would be thinner than the apple's skin. I'm afraid I must side with Ben in that targeting the crust with pinprick nuclear explosions in order to let Earth's raging interior do its dirty work is probably not an effective use of resources. Poke a hole in the crust, and it'll be a bit runny for a while. But it will crust over again soon enough.

What if I were to launch enough pure sodium toward Earth (from the moon) to eliminate its oceans? I'd have to use a rail gun and do it a little at a time. But using Ben's time-on-target approach (nice idea!) at multiple targets, I bet I could have a pretty serious impact on humanity.
 

Layla Nahar

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How about using anti-matter? I guess that is in the same realm as the black hole solution, right?
 

Pthom

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My gut reaction is that it would be much easier to destroy the ability of life to survive on a planet, than to destroy the planet itself.

The gravitational forces involved in holding such a thing as a planet together are incredibly immense. Could we break the Earth? Possibly. Could we make it disappear (without magic)? Probably not.
 

Bartholomew

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So how would you destroy a planet? And you must use scientifically plausible means.

If you were stationed on the moon, and you were tasked with destroying Earth, how would you do it? You can have as many chemical elements as you want in any quantity. What would you construct, launch, or ignite to destroy Earth from the moon?

If you destroy just the biosphere (every living thing), you get only partial credit.

Since you're stationed on the moon, you would ideally like to remain standing after you've accomplished your planetary destruction, so keeping the moon intact is desired. But, megalomania being what it is, you won't be penalized if you sacrifice the moon (and yourself) in your bid for global destruction.

So let's have it. What's your plan?

I would construct massive thrusters on the backside of the moon, pointed in such a direction as to force Luna to collide with Earth.

Earth pinwheels off course and sails into the sun. The remains of Luna resume orbit.

Because if the cueball goes into the hole, I lose my turn.
 

Astronomer

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I would construct massive thrusters on the backside of the moon, pointed in such a direction as to force Luna to collide with Earth.
Actually, if you want to push the moon into the sun, you need to mount your mass driver so that it shoots in the direction of the moon's orbit so that the moon's angular momentum is reduced. Mounting the mass drivers on the backside would just cause the moon to oscillate around the point where its center of gravity now orbits Earth, without reducing its overall angular momentum.

Orbits are peculiar things. A planet in orbit around a star (or moon around a sufficiently large planet) is as stable as a marble in a round-bottomed bowl. Push it in any direction, and it will tend to return to its center. You can even make it "orbit" around its point of stability, which is what putting the mass driver on the backside of the moon would accomplish.

A solid ring in orbit around a star (sound familiar?) is like a marble on top of a hill, stability-wise. Give it a slight push in any direction, and it will roll down, never to have the energy required to put it back in orbit (on top of the hill). Sorry, but Ringworlds are too unstable to work. Without constant and very energy-intensive adjustments to their orbits, they will always end up crashing into their suns.

And what about a Dyson Sphere? That's like a marble on a flat surface. It's not inherently stable, but it's not inherently unstable, either. The sphere isn't gravitationally pulled in any particular direction by the star within, regardless of where inside the sphere the star is. (This is assuming, of course, that the sphere is impossibly rigid.) Orbital (if you can call it that) adjustments would still need to be made, but there isn't a gravitational/centripital slope that's either hindering or helping you, so a sphere can be maintained a safe distance from its star far more easily than a ring.


Sorry, it's been a slow day. :)
 

Wojciehowicz

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If time and space were not an issue, nor were supply and energy, relativistic motion should suffice. E=mc^2. Use some other star system's moon or moon-sized asteroid. Use fusion to kick it in the pants, then move to a plasma accelerator, and finally an ion accelerator. When something of a considerable size strikes at .95c, BANG. If the moon were more of a cometary body with significant hydrogen available and you could do efficient fusion, with a body that size you could have immense power plants that would be part of the kinetic kill body itself.

It would take a lot of time, an a lot of accuracy. A little bit off at those speeds, and you miss entirely. But if you do it right, your impactor and whatever it hits are completely destroyed. The force of the event should scatter dust and gas all over the target solar system.
 

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Even allowing for the accuracy problem, where will the energy for the ion accelerator (or any other propulsion method) come from?

A moon-equivalent body at 0.95c has approx 6e42 joules of kinetic energy.

To get that much energy you need to annihilate approx 6.5e22kg of matter.

If you are fusing hydrogen for power you achieve annihilation of 0.7% of the hydrogen's mass. You therefore need to start with more than a hundred times more hydrogen than the body itself weighs.

Or have I made a miscalculation somewhere here? Haven't studiedphysics for quite a few years. :)
 

benbradley

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Sounds about right. I think such a moon hitting the Earth at a relative speed of 0.0005c would have plenty enough energy to destroy everything on the Earth's surface as we know it.

But that would be too fast. I like the idea of moving the Moon into a closer and closer orbit around the Earth, until the Roche limit of one or both is reached. That should be plenty enough to plow under everything on the Earth's surface. It would be so kewl, and there'd be some awfully big earthquakes well before the Roche limit is reached.
 

Wojciehowicz

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Sounds about right. I think such a moon hitting the Earth at a relative speed of 0.0005c would have plenty enough energy to destroy everything on the Earth's surface as we know it.

But that would be too fast. I like the idea of moving the Moon into a closer and closer orbit around the Earth, until the Roche limit of one or both is reached. That should be plenty enough to plow under everything on the Earth's surface. It would be so kewl, and there'd be some awfully big earthquakes well before the Roche limit is reached.

I considered that, but I wanted to go for bang, splat, kapow sort of destruction. Absolutely, your scenario would totally waste the surface. Tidal waves sweeping across entire continents would result long before the Roche limit was reached. Volcanic activity would be insane and the atmospheric damage would wipe out most life we know or care about (as in, everything above microbes). The weather would go crazy and there would be winds sufficient to scour whole cities off the map. When the end came, the rain of debris would be spectacular, if you were watching it from space.

Still, we might want to slow the Moon a little bit someday, to keep it where it is before it recedes to much more. Where it is right now works just perfectly for life as we are and are used to.
 

Wojciehowicz

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Even allowing for the accuracy problem, where will the energy for the ion accelerator (or any other propulsion method) come from?

A moon-equivalent body at 0.95c has approx 6e42 joules of kinetic energy.

To get that much energy you need to annihilate approx 6.5e22kg of matter.

If you are fusing hydrogen for power you achieve annihilation of 0.7% of the hydrogen's mass. You therefore need to start with more than a hundred times more hydrogen than the body itself weighs.

Or have I made a miscalculation somewhere here? Haven't studiedphysics for quite a few years. :)

It doesn't have to be the size of the moon. A moon, which means smaller or larger. At relativistic speeds, even a small body will cause a gigantic kinetic energy release that will disrupt the planet enough for mass to be scattered beyond gravitational recollection. A body the size of our Moon would not need to be going anywhere near that to do it, but would need to be moving way faster than the original impact between Proto Earth and whatever hit it, that gave us Current Earth and the Moon. The goal is to scatter the remaining mass too far for it to clump back together.
 

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It doesn't have to be the size of the moon. A moon, which means smaller or larger. At relativistic speeds, even a small body will cause a gigantic kinetic energy release that will disrupt the planet enough for mass to be scattered beyond gravitational recollection.

Apologies on misreading that, but the basic point about using a fusion power source remains - you still need a hundred times the mass of your chosen moon, and that just covers the hydrogen requirement and assumes total efficiency.

I certainly don't dispute that a massive relativistic mass is a good planet killer, I just don't see any means of propulsion suggested for accelerating such a projectile.
 

Nivarion

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Why would I destory the earth when I've got limitless supplies on the moon? I would rule over the earth from my space throne of evuls, safe in the knowledge that it is incredibly hard for farmboys got get to the moon.

Meanwhile, it would be relatively simple for me to hit their population centers with a massive rock whenever they refuse to show me the respect I deserve. Especially since it would be difficult for them to return fire.

Bwhahahahaha.

I think the notion that such things scale indefinitely is too easily accepted as fact. I don't buy it, and I've never thought Clarke's quote to be too insightful, except to the extent that it lends itself to the creation of remarkable SF stories.

I don't believe it is infinitely scalable. I believe that, when it comes to understanding of nature (and, thus, technology), there are plateaus that can be reached -- one of them being the automatic rejection of magic out of hand. I believe that to a sufficiently advanced civilization, no amount of advanced technology would be perceived as magic, simply because they've reached the point at which new phenomena are seen as just that: perfectly natural phenomena -- however unexplained -- and not something that must be explained by thundering gods or supernatural powers.

Aside: I hope the OP doesn't mind our derailing the topic and discussing this. Think he'd be mad if we continued down this path?

One of the stories in the que (I'm getting better, might start pitching a few soon) involves the captain of a war cruiser meeting up with an alien race who can use magic.

He pitches off clarkes law at one of their gods, who creates a new planet from nothing just to show him up. Full of primal life and everything.

Sufficiently powerful magic will be known as such.
 

Pthom

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Again, folks, this particular sub forum is NOT for discussing works of fiction, but for facts of science. This thread, as a whole, is very close to crossing that line. Certain posts in this thread have already done it. Please follow the rules of this forum and reserve speculative discussions for the main SF/F forum. Because of that, I am very close to moving this thread.

However, a point brought up by benbradley interests me, and that is the Roche Limit. I am curious: with a satellite such as our Moon, which is a little over half as dense as its primary, wouldn't there be significant damage to either body due to tidal stress long before the satellite reaches the Roche limit?

Especially with the Earth/Moon system, where there is tectonic activity and lots of water to factor in. The Roche limit for fluid bodies is not about half as great as for solid ones--I think the earthquakes and tsunamis we've witnessed during this decade would be minor comparatively.
 

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Well if we are assuming the hypothetical person on the moon is not an Earthling then he, or she of course, may use a much larger scale version of the propulsion used to get there and turn the moon into a large kamikaze craft and drive the Moon into Earth too fast for Roche's Law to turn it into a ring.

If the person on the moon is from Earth they will have a harder job of it. They probably do not have the resources to capture enough of the sun's energy to melt a planet and may not have available transport to the Asteroid belt. With such transport and sufficient resources and manpower they could rig engines on the largest asteroids (for instance those above 10 km in size) and send them all at Earth in a giant conga line of destruction. This would certainly wipe out life and might be enough to rate a B.
 

benbradley

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If the person on the moon is from Earth they will have a harder job of it. They probably do not have the resources to capture enough of the sun's energy to melt a planet and may not have available transport to the Asteroid belt.
I am again reminded of creating a very thin reflective foil (in space around the Earth-Moon system, from some small factory designed, assembled on and launched from the Moon), maybe just a few atoms thick, it only needs to be strong enough to hold together when random atoms hit it in space, made of aluminum, or something like mylar with a thin coat of aluminum. Much like what I wrote before:
...
The sun can shine on, but with space technology, it would only take a 1-mil or less reflective or absorptive film to stop all sunlight shining on the Earth, out at the L1 orbit between the Earth and Sun. This would be at least 8,000 (or larger due to paralax and the sizes of the Earth and Sun) miles in diameter, which could add up in mass, but this is just a little technology, not any new science. We've already got the James Webb Telescope being developed to capture a large amount of (very low-level) radiation in a precision way. All we want to do is block more of it.
... but this time to REFLECT extra sunlight onto the Earth. With an 8000 mile diameter mirror you could double the sunlight that hits Earth and we'd all be cookin' in no time at all (astronomically speaking), but even an increase of 20, 10 or 5 percent of sunlight on Earth would cause Global Warming worse than in Al Gore's worst nightmares. I'm thinking this would have the biggest bang for the cost of materials. You could have controllable mirror sections of a square mile each, and have them all reflect the Sun to a single point on Earth, giving a few city blocks the radiation of thousands of midday suns. All life would be gone in minutes. This would also be a really effective way of starting forest fires.

There's a point where extra sunlight (maybe a 50 percent increase?) would cause the Earth to heat up so much it could only support life at the poles, if at all. That's it, have two mirrors that reflect extra sunlight directly onto the poles, and the whole globe will become a supertropical not-paradise. Eat your heart out, Venus!