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Tarkus
2009-Jan-23, 02:08 AM
On the discovery Channel a while ago was an assessment of manned interstellar travel, you know the need for hybernation and vast velocity.


I got to thinking how implausible this really is. I mean at the kind of velocity needed to effectivly travel those distances a collision with even the smallest speck would surly be catastrophic, let alone a big chunk of debris.


Unless the void between systems really is quite empty, but somehow I doubt that.

Anyone have a view?

Gandalf223
2009-Jan-23, 04:28 AM
I think it's reasonable to assume that there is a great deal less solid stuff floating around in interstellar space, than here in our solar system. We've had equipment zooming around the solar system for reasonably long periods (though short by interstellar travel standards) without catastrophic damage in most cases. If the number of potentially damaging objects in interstellar space is a few orders of magnitude less than in a solar system, then the risk would probably be acceptable.

Anyone got numbers?

spoerl78
2009-Jan-23, 10:49 AM
From http://www.ccmr.cornell.edu/education/ask/index.html?quid=1026 :

It is estimated the gaseous density between stars in the Milky Way to be ~0.1 to 1 atom/cm3 (10-17 to 10-16 torr).

I think, you will be killed by radiation first!

Tzarkoth
2009-Jan-23, 02:17 PM
From another discussion we were having it was reported,


http://en.wikipedia.org/wiki/Ultra-high-energy_cosmic_ray Cosmic rays with even higher energies have since been observed, among them the Oh-My-God particle (a play on the nickname "God particle" for the Higgs boson), observed on the evening of October 15, 1991, over Dugway Proving Grounds, Utah. Its observation was a shock to astrophysicists, who estimated its energy to be approximately 3 × 1020 electronvolts (50 joules)— in other words, a subatomic particle with macroscopic kinetic energy equal to that of a baseball (142 g or 5 ounces) thrown at 96 km/h (60 mph).

It was most probably a proton with a velocity only very slightly below the speed of light. To a static observer, such a proton, traveling at [1 − (5×10−24)] times c, would fall only 46 nanometers behind a photon after one year.[3]

So, a spaceship traveling at near light speed would be pounded by baseballs in deep space and flying through Galaxies and or star forming regions would be even more problematic.

spoerl78
2009-Jan-23, 02:23 PM
You better "Raise Shields" while you travel!

antoniseb
2009-Jan-23, 02:26 PM
I think that planning for manned interstellar travel is not really practical at this time... but if you imagine that the earliest such a journey could begin is perhaps a hundred years from now, and that at that time nanotechnology is well understood and used, and that machine intelligence has pretty much taken control, the possibilities become more realistic.

Concerning the OP under these circumstances, I'd imagine that the surface of the spacecraft would be covered with many self-replicating nanobots, including an especially thick layer on the leading surface. When any dust particle hits the vessel, it will be harmlessly absorbed, and the damaged surface, and ionized bits deeper in will get repaired in plenty of time for the next hit.

Ross PK81
2009-Jan-23, 02:45 PM
The risk also depends on how far you want to go.

The risk could be so small that it's not worth worrying about if you're only travelling to the nearest star. But the more further you go, the more risk there will be of something hitting you, to the point where the risk really wont be worth taking.

The only solution I can think of is some kind of force field around your ship.

dhd40
2009-Jan-23, 03:18 PM
I got to thinking how implausible this really is. I mean at the kind of velocity needed to effectivly travel those distances a collision with even the smallest speck would surly be catastrophic, let alone a big chunk of debris.


Unless the void between systems really is quite empty, but somehow I doubt that.

Anyone have a view? (my bold)

The Universe IS really, really, really empty (I suspect that you think of "standard" matter!) . I remember a figure of about one hydrogen atom/cubic meter.
If it were much more, how could light travel to us from a distance of some 14 billion light years without being scattered many times? We would see only very fuzzy images (if at all) of these distant galaxies, etc.

Therefore, don´t worry. But, of course, if you´re heading at the speed of c toward the full moon, ....:cry:

Ilya
2009-Jan-24, 01:39 AM
I think it's reasonable to assume that there is a great deal less solid stuff floating around in interstellar space, than here in our solar system. We've had equipment zooming around the solar system for reasonably long periods (though short by interstellar travel standards) without catastrophic damage in most cases. If the number of potentially damaging objects in interstellar space is a few orders of magnitude less than in a solar system, then the risk would probably be acceptable.

However, each and every probe and satellite had been hit by microscopic particles many times -- on the order of a hundred per year. Such dust impacts, harmless at interplanetary velocities, would be quite serious at relativistic speed.