[extropy-chat] stardust at home

spike spike66 at comcast.net
Sun Jan 22 00:50:21 UTC 2006

> -----Original Message-----
> From: extropy-chat-bounces at lists.extropy.org [mailto:extropy-chat-
> bounces at lists.extropy.org] On Behalf Of spike
> Sent: Saturday, January 21, 2006 4:27 PM
> To: 'ExI chat list'
> Subject: RE: [extropy-chat] stardust at home
> > bounces at lists.extropy.org] On Behalf Of spike
> ...
> > ...but the real reason to do
> > this would be to increase the rotation rate of the planet.  Once
> > we spin it up to about a milliradian per second, from its current
> > ~72 microradians per second, stuff at the equator becomes
> > nearly weightless.  That is a good starting point for taking
> > material off of the planet... spike
> How long would this take?  I did a quicky back of the
> envelope one digit calculation and get about ten million
> years... spike

Oops I goofed this.  The earlier calc assumed conversion
of energy of the photons, but the description of the 
method (reflecting photons westward) is a conservation
of momentum technique.  So assuming the mirror reflecting
westward notion, it would take ~700 billion years to
spin up the earth to a milliradian per second.  We don't
want to wait that long.  So we still need to convert
solar energy into some form suitable for hurling mass
westward, as opposed to simply reflecting photons out
that way if we wish to achieve the 90 minute day.


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