Space/Science — HabitableZone

Space/Science » in reply to only 26 rocks from Mars

So did you not read or not get the link that explained why discoveries are such a small fraction of exspected infall?
Buster — (archived)

ET's post below also explains why we know the interiors are not superheated. A link to the full article was provided earlier somewhere and some of the other links also touch on this. The boulder comment by Clark Barry keeps mentioning probably is intended to address the issue of ablative destruction of meteoroids as they enter the atmosphere rather than a need for that much rock to protect against space radiation which is clearly contraindicated by laboratory data. Unfortunately since Barry seldom posts complete articles or links to them we only get the quick shots easy to misinterpret.

The reason most of the meteorites that fall to Earth have only a thin crust indicating high temperature exposure is that the heating is so much faster at the surface than the rate of transfer through the rock that the surface reaches boiling point and vaporizes. Most of the heat by far from atmospheric friction goes into vaporizing surface rock rather than heating the interior. Phil Plait's Bad astronomy site covers this phenomena in more detail. This discussion does indicate however that cm sized material ejected from Mars is unlikely to reach the surface. I'm not sure the comment "lands on Earth every month" is accurate. Strikes Earth's atmosphere maybe, but it takes a big rock to reach the surface. I believe 20 or 30 m is considered the lower limit, but that may be the limit for remaining intact and not include those multiple meteorite infalls from a shattered body.

see ya

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