[ExI] Alpha Centauri

[BillK]

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
the Universe.
(which is still accelerating).
<http://www.gizmag.com/hubble-spitzer-expansion-universe-redshift-cepheid/24457/>
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
reach.


BillK