From: hal@finney.org
Date: Tue Feb 06 2001 - 20:16:00 MST
> http://news.bbc.co.uk/low/english/sci/tech/newsid_1154000/1154784.stm
>
> By BBC News Online science editor Dr David Whitehouse
> Mankind will soon have the ability to move the Earth into a new orbit, say a
> team of astronomers. The planetary manoeuvre may more than double the time
> life can survive on our planet, they believe.
This is amazing, although I'm sure there will be a lot more changes than
this in a billion years(!). But it is a good illustration of the general
principle that chaotic systems are easily controlled. The solar system is
surprisingly chaotic, as the article mentions later:
> Earth's gradual outward migration may require adjustments to be made to the
> orbits of other planets as well. Recent calculations of the Solar System's
> stability indicate that if the Earth was removed then Venus and Mercury would
> become destabilised in a relatively short time.
With a chaotic system you mostly need good short-term modeling and
prediction. Then you make small changes that keep you centered on the
path you want to follow. It's the same basic principle you use when
riding a bicycle.
Hal
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