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Comment by rkaplan | Hacker News Reader

I found the footnote particularly interesting:

"The Moon has no oxygen atmosphere, so how can something explode? Lunar meteors don't require oxygen or combustion to make themselves visible. They hit the ground with so much kinetic energy that even a pebble can make a crater several feet wide. The flash of light comes not from combustion but rather from the thermal glow of molten rock and hot vapors at the impact site."

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(As you know Bob,) Explosions are kind of like rocket engines. They (generally) don't require external oxygen to happen. Quite a lot of explosions are solids (e.g. TNT) turning into a bunch of N2.

On the other hand, if something creates a bunch of gas in space, there's really no medium for a shock wave, other than the gas created. So it's not going to be as damaging. Though, there's no reason a sub-lunar explosion would be much different that what we get on the earth.

Combustion doesn't make things explode; it just heats things up so they vaporize. But there are other ways to heat things up, too, and the end result is the same.

I thought it was a weird footnote. I mean, do people really think that the rock would burn even if there was oxygen?

I suspect many meteors can and will combust. Lot's of things love oxygen bonds once they get enough energy and there is not a lot oxygen or heat in space.

PS: Think Class D Fire http://en.wikipedia.org/wiki/Fire_classes

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