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Fiery Phoenix
2008-Oct-15, 03:24 PM
In interstellar space, we have cosmic clouds, dust, supernova remnants, and star stuff. All of which could somewhat affect a spaceship - or at least can be seen by observers, so it's not really "empty space".

Now, is intergalagtic space the same? I mean, in there, we probably wouldn't see anything other than points of light spread throughout the place (galaxies). Or is there something similar in the space between galaxies, the real space? I don't think supernova remnants even exist in intergalagtic space, as I assume they are within the limits of the galaxy where they belong. I do think that there might be some remaining stuff from the Big Bang 14 billion years ago, though, but is there anything else? Also, would a spaceship feel a difference in intergalactic space?

I'm just curious, like all scientists. Except, of course, I'm not a scientist. LOL! :lol:

Thanks in advance, everybody!

Saluki
2008-Oct-15, 03:56 PM
Intergalactic space certainly contains less than intragalactic space, but it is not empty. At the macro scale there are occasional rogue stars/planets/debris/etc. On the micro scale, there are various subatomic particles popping in and out of existance.

Cougar
2008-Oct-15, 07:44 PM
I do think that there might be some remaining stuff from the Big Bang 14 billion years ago, though, but is there anything else?

Beyond what Saluki said, we expect halos of dark matter to extend well beyond the visible edges of galaxies. Whether there are wisps of dark matter out in the voids is apparently unknown... probably because there is no way to see any evidence of such.

As to the "remaining stuff from the Big Bang," namely hydrogen and helium, there may be a little out between the galaxies I suppose, but of course most such stuff was drawn in to the nearest gravitational infall, ending up in galaxies.

Then there is the possibility of dark energy or vacuum energy pervading all space, from the matter-rich regions to the vast voids.

joema
2008-Oct-16, 01:00 AM
Now, is intergalactic space the same? I mean, in there, we probably wouldn't see anything other than points of light spread throughout the place (galaxies)...
If you looked out the window of a hypothetical intergalactic vehicle while in-transit (assuming sub-light speed), there would be no stars -- just total blackness. It would be like looking at the M31 Andromeda Galaxy from earth, but with all other stars removed. Just complete blackness with a few dim smudges of light that are galaxies.

Fiery Phoenix
2008-Oct-16, 06:08 AM
If you looked out the window of a hypothetical intergalactic vehicle while in-transit (assuming sub-light speed), there would be no stars -- just total blackness. It would be like looking at the M31 Andromeda Galaxy from earth, but with all other stars removed. Just complete blackness with a few dim smudges of light that are galaxies.

That's exactly what I thought. Thanks, guys!

One more thing, how would a spaceship feel in intergalagtic space? I know we can't know that for sure, but I'm curious to see what you, gentlemen, have to say about it.

Eroica
2008-Oct-16, 11:55 AM
I do think that there might be some remaining stuff from the Big Bang 14 billion years ago, though, but is there anything else?There certainly is an Intergalactic Medium (IGM) in the space that lies outside clusters of galaxies; for the most part it consists of highly rarefied plasma that was reionized mainly by the high-energy UV light of the first stars (especially giant Population III stars) and possibly also by high-energy emissions young active galaxies.

Interspersed in this IGM are cooler denser clouds of mainly neutral atomic hydrogen known as Lyman-Alpha absorbing clouds, because their presence is betrayed by the Lyman-Alpha absorption lines they produce in the light from very distant quasars. (These lines are red-shifted by the cosmological expansion of space, so that the light which reaches Earth has a whole series of such lines at different wavelengths - the so-called Lyman-Alpha forest.)

Finally there are some particularly dense Lyman-alpha clouds known as damped Lyman-alpha systems. The density of neutral atomic hydrogen in these clouds is about a million times that of the surrounding IGM. These may be regions in which new galaxies are beginning to form.

Cougar
2008-Oct-16, 02:51 PM
Interspersed in this IGM are cooler denser clouds of mainly neutral atomic hydrogen known as Lyman-Alpha absorbing clouds....

:doh:

Invader Xan
2008-Oct-16, 11:17 PM
Actually, there's at least one huge intergalactic cloud on a collision course with the Milky Way: Smith's cloud.
http://en.wikipedia.org/wiki/Smith%27s_Cloud
If it were visible, it would be the size of the Orion constellation! In about 27 million years all of that hydrogen impacting the Milky Way is likely to cause a huge starburst!

How would a ship feel in intergalactic space? Very lonely, I'd imagine. ;)

Also, streams of plasma interconnect nearby galaxies. The Magellanic Clouds are both interacting with the Milky Way via the Magellanic Stream -- a tenuous stream of hydrogen plasma and the occasional rogue star linking the galaxies together. If that were visible, it would stretch across 180 degrees of the sky.

Noclevername
2008-Oct-17, 11:59 PM
The light radiated from galaxies, and the cosmic microwave backround radiation, permeate intergalactic space.