Re: SPACE: Beyond Apollo (was: a to-do list for the next century)

From: Robert Bradbury (
Date: Tue Apr 04 2000 - 23:30:24 MDT

On Wed, 5 Apr 2000, Damien Broderick wrote:

> At 05:19 PM 4/04/00 -0400, Robert wrote:
> >Of course I'll point out before one of our rocket jocks jumps
> >on it, that Venus Lite is going to require some changes in its
> >orbital velocity...
> Why? Because mass-driving all that matter out of the pithed planet will
> kick hard? Fire it off in all directions, or just hither and yon, to and
> fro, forward and aft, carefully.

Yes, thinking about it that way, the mass removal would seem to
remove the momentum as well. For some reason, an evil magical
physics method of "disappearing" the mass must have entered my
mind when I was thinking about this.

> >Just out of curiosity, if you make the
> >planet 1/10th its former mass (with the same volume), how
> >much are you going to have to change the length of its year?
> Why should it have any effect? An asteroid at 1 AU would take a year to jog
> around, surely. A Jovian ditto.

If it is forms at 1 AU, yes. I was thinking more of the problem
of having the momentum of a larger body at 1 AU, but suddenly
having the mass of an asteroid. But as you point out (indirectly),
thats kind of hard to manufacture in reality...


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