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The Long-term Future Of Space Travel, Where can we go in the Cosmos?
ljk4-1
post Nov 9 2005, 04:20 PM
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Astrophysics, abstract
astro-ph/0509268

From: Jeremy S. Heyl [view email]
Date (v1): Fri, 9 Sep 2005 21:49:22 GMT (18kb)
Date (revised v2): Tue, 8 Nov 2005 05:13:13 GMT (18kb)

The Long-Term Future of Space Travel

Authors: Jeremy S. Heyl

Comments: 5 pages, 3 figures, minor changes to reflect version accepted to PRD

The fact that we apparently live in an accelerating universe places limitations on where humans might visit. If the current energy density of the universe is dominated by a cosmological constant, a rocket could reach a galaxy observed today at a redshift of 1.7 on a one-way journey or merely 0.65 on a round trip. Unfortunately these maximal trips are impractical as they require an infinite proper time to traverse. However, calculating the rocket trajectory in detail shows that a rocketeer could nearly reach such galaxies within a lifetime (a long lifetime admittedly -- about 100 years). For less negative values of $w$ the maximal redshift increases becoming infinite for $w\geq -1/3$.

http://arxiv.org/abs/astro-ph/0509268


--------------------
"After having some business dealings with men, I am occasionally chagrined,
and feel as if I had done some wrong, and it is hard to forget the ugly circumstance.
I see that such intercourse long continued would make one thoroughly prosaic, hard,
and coarse. But the longest intercourse with Nature, though in her rudest moods, does
not thus harden and make coarse. A hard, sensible man whom we liken to a rock is
indeed much harder than a rock. From hard, coarse, insensible men with whom I have
no sympathy, I go to commune with the rocks, whose hearts are comparatively soft."

- Henry David Thoreau, November 15, 1853

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Guido
post Jan 29 2006, 03:34 PM
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QUOTE (ljk4-1 @ Nov 9 2005, 06:20 PM)
Astrophysics, abstract
astro-ph/0509268

From: Jeremy S. Heyl [view email]
Date (v1): Fri, 9 Sep 2005 21:49:22 GMT (18kb)
Date (revised v2): Tue, 8 Nov 2005 05:13:13 GMT (18kb)

The Long-Term Future of Space Travel

Authors: Jeremy S. Heyl

Comments: 5 pages, 3 figures, minor changes to reflect version accepted to PRD

The fact that we apparently live in an accelerating universe places limitations on where humans might visit. If the current energy density of the universe is dominated by a cosmological constant, a rocket could reach a galaxy observed today at a redshift of 1.7 on a one-way journey or merely 0.65 on a round trip. Unfortunately these maximal trips are impractical as they require an infinite proper time to traverse. However, calculating the rocket trajectory in detail shows that a rocketeer could nearly reach such galaxies within a lifetime (a long lifetime admittedly -- about 100 years). For less negative values of $w$ the maximal redshift increases becoming infinite for $w\geq -1/3$.

http://arxiv.org/abs/astro-ph/0509268
*


I believe that the long-term future of space travel will not be manned spaceflights with astronauts / cosmonauts / taikonauts / ...
It will be space flights "manned" with robots capable of doing everything a human can, and without the limitations humans have. Our minds will once wander the galaxy, but certainly not our bodies.
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