[ExI] fermi paradox- weighted summary

Rafal Smigrodzki rafal.smigrodzki at gmail.com
Thu Dec 6 23:40:23 UTC 2007

On Dec 6, 2007 9:36 AM, BillK <pharos at gmail.com> wrote:
> On Dec 6, 2007 1:45 PM, Eugen Leitl wrote:
> >
> > At 0.9 c, the distances are very, very short.
> >
> If you allow unknown technology, anything is possible.
> (Or, at least no presently available technology, or speculative
> technologies that may never become feasible).
> Seth (and you) know that 0.9c travel requires huge energy use and
> tremendous radiation shielding. (And you need wild speculation to
> permit this). He even provides a link to such speculations for you.
> <http://www.space.com/businesstechnology/060308_exotic_drive.html>
### Huge radiation shielding is not really necessary, except at
high-sublight speeds, unlikely to be achieved anytime soon. Otherwise,
all you need is appropriate body modifications. We know that it's easy
to achieve survival at doses 15000 Gy and higher, without
nanotechnology. The radiation fluxes in LEO are in the range of 0.02
mGy/day. You would need to travel for a bit more than 2 million years
to accumulate this kind of dose.

If you need 2 million years to travel to the nearest star, don't
bother to go: somebody else will be there before you.


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