The expanding Universe and Galactic collisions

These questions aren't easily answerable in a short forum post. I suggest you read "The Fabric of the Cosmos: Space. Time. And the Texture of Reality" by physicist Brian Greene. I'm currently reading it, and it goes into some detail (without maths, which means of course that it doesn't go into detail AT ALL, lol) about the current theories. Most of the concerns you have about (your personal ideas about) "the" Big Bang theory, have been addressed for some 30 years already by the concept of Inflation. Which basically is an extremely short period in the extremely young universe, in which space expanded exponentially (from a size smaller than an atom, to something in the order of magnitude of the size of the currently visible universe if I remember correctly). And Inflation (as often, there are different flavours of the theory) is not just a convenient assumption to make theory match observation. It actually predicted properties of the cosmic background radiation with astonishing accuracy. Green shows a graph of the prediction (a complex curve, not just something linear), and the same graph with the datapoints from measurements, and if it would be a test for God, I would now believe in God ;-)!

Another nobel prize if you answer this one

I'm certainly not a cosmologist or quantum-physicist, but I think as "mere mortals" we'll have to accept that reading websites like those, or reading popular books will not be able to answer some questions as satisfyingly as we would like. Popularizers like Brian Greene and others point this out all the time: the REAL theories are in the complex maths, and nitpicking or pointing out inconsistencies and absurdities on the basis of the "plain English" version is pretty futile. That's an important thing to understand.Like in many scientific areas, we have little choice but to trust the scientific community, and trying to be as well informed as possible to seperate junk from mainstream or at least reasonably assess how much a particular idea is supported or rejected by evidence and consensus.Bottom line: don't get your hopes up too high when it comes to achieving Real Understanding on the basis of anything else but the bare mathematics.

I'm reminded of this almost EVERY day when I read through the "reader letters" segment of our local newspaper. Specifically when Global Warming gets debunked by people who base their idea of GW on what the evening news tells/shows, and can't even spell "isobar". Style "september was .5 degrees colder than normal, so where's this Global Warming, again???" Initially I always get this urge to write a response, but then I realise how little it would achieve...What is the saying again? "The more you know, the more you know how little you know."