I have a hard science weapon question for you guys:
Given a 12 gram vanadium steel projectile impacting a target at a velocity of 18,600,000 meters per second (10% of the speed of light) what is the energy transfer in joules?
I'm postulating a magnetic mass driver as a space weapon and need to get a handle on the destructive capacity of the weapon.
Regards,
Scott
Firstly, that doesn't look quite like 10 percent of lightspeed (Yes, I actually remember figures such as 186,282 miles per second as lightspeed), so I googled:
18,600,000 meters per second in miles per second
and got:
[SIZE=+1]18600000 (meters per second) = 11557.5042 miles per second[/SIZE]
The copy/paste thing is strange here, I didn't ask for that font size, but anyway, that's only about 6.2 percent of lightspeed, still a respectable speed and a helluva lot of energy in 12 grams of metal.
This brings up other questions as well as the energy in the projectile. How thick is the object it strikes, and what is it made of? For any man-made device or ship currently or ever in outer space, your projectile will make a hole through it and barely slow down. The hole might splatter out on the other side, I'm not sure. If the struck object is thick and dense enough to stop the projectile (something made of steel several feet or tens of feet thick, maybe even thicker), then much of that energy will be released as heat and light. The bit of steel will melt, vaporize, and might even get hot enough for fusion, all in a small fraction of the blink of an eye. Take KanShu's calculation and compare with the output of a megaton or TNT or various size nuclear bombs.
Looking online, a kiloton of TNT is about 4*10^12 joules (
http://en.wikipedia.org/wiki/Megaton), about the size of a quite small nuclear explosion (a "small" nuclear bomb test is expected to be about 10 kilotons of TNT, but North Korea's recent test was believed to be less than one kiloton:
http://en.wikipedia.org/wiki/2006_North_Korean_nuclear_test).
I was going to suggest the Usenet newsgroup rec.arts.sf.science for this question, but with KanShu's help, I think I've done well with answering it.
So in layman's terms how bad does that jack up the Enterprise?
Depends on where it hits. It would likely leave just a small hole through it (compared to the larger one the dish part got in one of the movies), but if it hits a thick, dense object or the antimatter containment vessel (whatever that's called, I just know it's not a Jeffries tube), there could be big problems.