Say you could move infinitely fast/gravity doesn't affect you. You move in a straight line. Do you hit anything, like stars or black holes? Not talking about cosmic dust.
Asked
Active
Viewed 118 times
1 Answers
1
No.
The question is a bit vague, but I try to answer it in spirit. Remember Olbers' paradox, which asks why the sky is dark at night. In an infinitely large, infinitely old universe, one should see stars in all directions. From all we know, the universe may be infinitely large, but it is only 14 billion years old, so light from further away hasn't had time to reach us. Thus, the night sky is dark.
Turning this around, you can travel along any direction and with the same probability that the night sky is dark and not star-surface bright, not hit anything.
Now obviously there is any number of caveats... around here, there is about one star every parsec, and they have a million kilometers in diameter. If you start out near the center of a galaxy, the story may look different. Conversely, once you made it out of the Milky Way, the probability would drop drastically even more. You mention black holes, these are just old stars too in this context. Then there's planets but their surface area is tiny compared to that of stars, so we can neglect them. Gas and dust is more fun: you are guaranteed to encounter that! All along the way, essentially all the time. Another thing you are encountering all the time are cosmic rays of all kinds and energies, and of course, the background light from the cosmic microwave background.
rfl
- 6,545