That’s kind of, basically, the source of the question. We know that earlier stars are the source of most of the matter in the planets, and that humans and other creatures depend on the stars to navigate and cosmic rays cause mutations, both good and bad. But now that we’ve evolved and are standing on billions of tons of higher elements that were formerly star stuff (in Carl Sagan’s famous phrase), what does the rest of the universe mean for us?
The Doctor Who episodes “The Pandorica Opens” and “The Big Bang” are about the destruction, and eventual restoration, of the entire universe other than the Earth, Moon and Sun.
Ben Reich in Alfred Bester’s The Demolished Man had a rough night, when the stars, planets, Sun and Moon all disappeared.
(Beverly Crusher replies “The same thing happened to me!”)
This is only true of the universe on a large scale – i.e.- the more distant galaxies. It’s not true within any given galaxy like the Milky Way, which is held together by gravitation. It’s not even true with our Local Group of 20-some galaxies, where relative motion can still overwhelm the expansion of space. In fact the Andromeda Galaxy is rushing toward us at about 110 km/s (around 250,000 mph) and will collide with the Milky Way in about 4.5 billion years.
Such a body would, by definition, have zero velocity and zero kinetic energy.
I was basing my answer off of information, mainly from this video. It is more likely than not that I mistook what he was saying.
Don’t be too sure about this. It’s common to post that this is a fairly sure thing (and I’ll admit to having done so), but some recent research casts some doubt about it. Bad Astronomer column:
Anyway, we’ll have a much better idea of what the transverse velocity of Andromeda Galaxy is in 5 to 10 years. If it’s below about 50 km/sec, brace yourself for a head-on; if it’s over about 80 km/sec, relax, not going to happen. In between, the two may perform a do-si-do or two before tying the knot.