[AR] Re: kinetic ICBMs (was Re: Nothing to do with rockets.)
- From: Henry Spencer <hspencer@xxxxxxxxxxxxx>
- To: Arocket List <arocket@xxxxxxxxxxxxx>
- Date: Wed, 6 Oct 2021 01:12:52 -0400 (EDT)
On Tue, 5 Oct 2021, roxanna Mason wrote:
On that note, I wonder what the impact velocity of the Nickel/Iron meteor
was that made the Barringer crater in Arizona.
It is thought to have been about a 45m object, 400,000t, hitting
atmosphere at about 17km/s. It partially broke up circa 14km up -- even
the strength of iron was greatly exceeded -- and only about half its mass
reached the surface more or less as a single lump, hitting the ground at
about 12km/s. Older models showed higher impact velocities, but struggle
to explain why there is so little impact melt in the crater, a result that
appears naturally with these numbers.
Caveat: the numbers are inference and modeling from limited evidence, not
constrained very tightly by the data. Planetary scientists are prone to
trying to extract lots of knowledge from meager data :-), and there are
sometimes major surprises when better data appears.
Henry
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