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View Full Version : Bad Astronomy Alert (maybe): Nova on Mass Extinction



t-bonham@scc.net
2008-Aug-14, 07:38 AM
A recent story on PBS from the Nova Science series talked about 'Mass Extinctions' of life on earth over the past millions of years. It talked specifically about the one that caused the extinction of the dinosaurs. That one is known to be the result of a massive asteroid strike in central Mexico.
They showed a graphic sequence of that -- a large asteroid ("Mount Everest size") traveling through space and striking the Earth.

But in this sequence, they show the asteroid as rotating or turning randomly as it travels through space. I'm wondering if that is accurate, or an example of bad astronomy?

(I don't have any expertise in this field, but it seems to me that any such rotation would have been damped down by gravitational forces during the travel through space, and so this asteroid would NOT have been rotating as it approaches the Earth.)

WaxRubiks
2008-Aug-14, 08:04 AM
AS far as I know: any free falling body can rotate, and will remain rotating, due to there being no air resistance to slow it down, but it has to be along a fixed axis(ie not random).

there are probably far more complex limits on the rotation of a free falling body, but I do not really know much about them.