[ExI] Expansion of the Universe

[Kelly Anderson]

Unless the speed of light is overcome somehow...

-Kelly


On Sat, Dec 29, 2012 at 2:19 AM, BillK <pharos at gmail.com> wrote:

> Ethan Seigel has done another interesting post.
> <
> http://scienceblogs.com/startswithabang/2012/12/28/the-universe-beyond-our-reach/
> >
>
> Quotes:
> Because of the expanding Universe, the farther away a galaxy is, the
> faster it appears to be moving away from us, or the more redshifted
> its light is. This image — from a section of the Hubble Ultra Deep
> Field — shows the highest redshift galaxies ever discovered. And yet,
> you don’t need to be this extreme to already be out of reach: any
> galaxy with a redshift of 1.8 or more, or that’s more than about 16
> billion light years distant right now, is already beyond our reach.
>
> Not even if we had a relativistic spaceship, not even if we could
> travel at the speed of light ourselves could we reach it. Our first
> radio broadcast will never be received by those galaxies, and in fact
> nothing we do from now on can ever affect them. They’re already gone.
> In fact, the part that is presently within our reach encapsulates just
> 4% of the volume of the presently observable Universe!
>
> And it’s only going to get worse over time; as the Universe’s clock
> ticks by, the objects closer to that edge continue to expand away,
> receding progressively faster from us. While we might be able to reach
> the Virgo cluster now, in 100 billion years, it too will be gone. In
> 100 billion years, I should clarify, this will be all that’s left.
> The local group. Ourselves, Andromeda, and our mutual satellite
> galaxies. That’s it.
> -------
>
>
> So much for humanity expanding throughout the universe.
> If humanity is ever able to reach another galaxy, we'll only get to
> the nearest few out of 200 billion galaxies.
>
>
>
> BillK
>
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