[extropy-chat] Pluto New Horizons launch -getting ready

[Russell Wallace]

On 2/17/06, spike <spike66 at comcast.net> wrote:
>
> Good question thanks.  You are right: it is a puzzling output of the
> finite
> element sim they were running, but it makes sense.  Above a certain
> velocity, the mass of the projectile did not result in significant change
> in
> the diameter of the hole.  The length of the projectile is directly
> proportional to the depth of the hole and the projectile velocity is
> directly proportional to the diameter of the hole.
>

That doesn't sound right. Consider extreme cases: taking a 1 meter
projectile with a mass of 1 ton, suppose the velocity were 0.5c; then the
crater depth would be far more than a few meters. Or suppose it were made of
aerogel, then the diameter would be substantially reduced.

I'm wondering whether the above conclusions are approximately correct within
a certain range of density and velocity, or whether there are effects the
simulation in question didn't take into account, or what.

(I read somewhere that all impact craters are roughly the same shape,
diameter something like 20 times the depth, with the dimensions being
proportional to the cube root of energy; but I don't have a reference to
hand, and don't know whether the statement is true or not.)

- Russell
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.extropy.org/pipermail/extropy-chat/attachments/20060217/4806ceda/attachment.html>