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Re: Impacts and ETs



--- David Marjanovic <david.marjanovic@gmx.at> wrote:

> 
> I think you've misunderstood this. The idea is that
> without a large moon the 
> Earth would lose balance and tip over at chaotic
> intervals. 

  A large moon can be dangerous. Ours has slowed
Earth's rotation from 18 to 24 hours IIRC. What if it
was barely fast enough at the beginning? Slow rotation
could have the same effect as obliquity
shifts-temperature extremes.


>Like Mars has 
> done -- on Mars there's no evidence of plate
> tectonics, but plenty of 
> glacial features on the equator. 

  Where on the equator? Surely you don't mean the
Valles Marineris, or the circumchrysean outflow
channels.



>Imagine an
> obliquity shift of 90° that 
> takes, I don't know, days, or perhaps centuries, as
> opposed to one of 20° 
> that takes 40,000 years. Just imagine. 
> 

 AFAIK in the Mesozoic it wasn't cold enough for much
ice to form even at high latitudes in winter. It
wouldn't have been as bad.
> 


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