[ExI] Alpha Centauri
pharos at gmail.com
Wed Oct 17 09:30:36 UTC 2012
On Wed, Oct 17, 2012 at 10:02 AM, BillK wrote:
> Using present rockets, about 50,000 to 100,000 years.
> So we need new rocket systems first.
And another thing that has been worrying me a bit is the expansion of
(which is still accelerating).
The new value for the Hubble constant, good to within three percent,
is 74.3 kilometers per second per megaparsec (km/s/Mpc).
What this means is that a galaxy one megaparsec away (that is, 3.26
million light years) will be moving away from us at 74.3 km/sec. If
you double the distance to 2 megaparsecs, a galaxy would be moving
away at twice that speed, or 148.6 km/sec.
74.3 kilometer/second = 166 204 mph
148.6 kilometer/second = 332 408 mph
That's a very long way away, but it is a bit discouraging that the
universe is expanding at a much faster speed than our best rockets can
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