In TML Msg. No. 7182, Mark Cook [email removed] writes:
>Now what *I* want to know is how to calculate liberated energy from
>a nominally non-elastic collision. The Shoemaker-Levin (sic) comet
>is going to hit Jupiter in July, and I'd like to know how many ergs
>will be released when several 4-kilometer in diameter chunks of ice
>slam into a nice, thick hydrogen laden atmosphere at 60 km/sec.
I did some calculations along these lines with a _Covenanter_-class
starship crashing into an airless body with its maximum vector.
I assumed that in the non-elastic collison, all of its kinetic
energy was liberated. The equations ran:
Kinetic Energy = 0.5 * mass * (velocity squared)
Mass of ship = about 4000 metric tonnes = 4 million kg
Max. vector = 80 G-turns = 1330 kps (= 0.4 % lightspeed)
KE of ship = 0.5 * 4000000 kg * (1330000 m/s)^2
= 3.54 * 10^18 joules
= 840 megatons TNT
Some useful information on this sort of thing is in "Space FAQ 04/13 -
Calculations" in newsgroups sci.space, sci.astro, or news.answers.
(1 MT = 4.2 * 10^15 J) conversion came from that document, and there
is also an equation for meteor impact craters among other things.
I don't know what effect an atmosphere would have on these rough
figures. Spacecraft are deadly weapons. Note that a Virus-controlled
suicide ship attacking, say, a starport in this fashion would
appear on ground-based 10 hex sensors at their maximum possible
detection range of 80 hexes *one 30 minute turn* before impact.
I suspect quite a bit of that sort of attack happened during the
Crash. (no pun intended)
- --Steve
PS Should be some interesting pictures from the Galileo probe of
the Shoemaker-Levy impact...I don't know if it's too bad that
the impact will happen behind Jupiter from the probe's
distant perspective, or a Real Good Thing (that flash will
be pretty bright...even though the comet's going a lot slower
than the above example, it's a lot more massive, too).
*******************************************************************************
Steve Bonneville | "Beware the tablespoon my son,
| The teeth that bite, the Claus that catch,
[email removed] | Beware the Subjects bird, and shred
| The serious Bandwidth!"
*******************************************************************************