Physics/gluons and vacuums
Me and a ex-mechanical engineer were talking about what was in "space". I was always under the impression as long as there is space, there will be some sort of gluon or other quantum element present, but my friend had told be that things in some parts of space, like a vacuum, had nothing in it, absolute nothing, no gluons and no quarks. Is this true? What are the implications of fact like this, more simply put, what would happen if a spaceship were to fly through absolute nothing?
A side question, what is the universe expanding into?
It's empty, but not really. I know, that doesn't make sense...but basically empty space is filled with particle-antiparticle pairs that pop into and out of existence all the time. It's a quantum phenomenon, enough energy can essentially be "borrowed" from empty space for a very tiny amount of time to create the pair, but then within a very short time (determined from a version of the uncertainty principle) that pair must annihilate and disappear back into the vacuum. One result result, if you want more information to google, is the Casimir effect. That occurs when two metal plates are spaced very closely to one another. The difference in quantum fluctuations of photons outside of the plates and the ones inside (limited by the small amount of empty space between them) results in a force that pushes them together. This is not some random theory, it's been measured. Wikipedia has a lengthy and accurate article on it, if you want to want to read a lot about zero point energy and such. So there's no such thing as empty space, but space is pretty close to empty. When scientists use quantum theory to figure out how much quantum energy should exist in empty space, they come up with enormous numbers. Why empty space isn't even more empty than it is...that's an ongoing research question. But a spaceship flying through truly empty space (which doesn't exist) wouldn't experience anything in particular. Space is full of only the tiniest amount of energy like that as it is, you'd have a tough time telling the difference.
I get that side question a lot, I've learned that it's best to tell you that it's not a question and direct you here: http://www.universetoday.com/1455/podcast-what-is-the-universe-expanding-into/
for a lot more information.