[ExI] (NASA.gov) NASA to chronicle close Earth flyby of asteroid (fwd)
spike66 at att.net
Sun Feb 17 03:10:40 UTC 2013
On Behalf Of Tomasz Rola
On Sat, 16 Feb 2013, spike wrote:
>>... Regarding your notion of a physical impact, this might transfer some
> momentum, and here's how you estimate how much: find the speed of
> sound in the rock, take the closing speed and calculate a cone going
> aft from impact site outward along the path of the impact. Then
> calculate a cone with the longitudinal axis being the closing velocity
> and both transverse axes being
>...Spike, thanks for hints. However... well, I don't know... I mean you
sound like honest and good man, but why on earth would you like me to do
such horrible things?
>...But ok, I will do like you say, only later, ok?
OK, I didn't state it very clearly. Let me try it Damien Broderick style.
You have perhaps seen what happens when a BB is fired at a glass window. It
often creates a cone-shaped punch-out, with the impact side hole the size of
the BB and increasing in radius along the path of the BB. When an impactor
hits a meteoroid at sufficient velocity, we can expect a hole the size of
the impactor on the impact side, increasing in radius as we go back, with a
cone half angle of about 4 to 8 degrees.
With that information, we might be able to estimate the momentum transfer to
the meteoroid, which I fear might be disappointingly small. At those speeds
I doubt it would break up the rock, but rather would punch a clean
cone-shaped hole. Of course our intuitions fail for we have little or no
experience in real life with impacts at 20 km/sec.
I would like to see a good simulation of it however.
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