Before anything else, I want to answer your final question first: Why and how is it here? I don't really care. The need to have an answer for everything is a religious trait, one I don't share. Science may always seek answers to any question that presents itself, but science insists on having a plausible answer, where it seems Christians are willing to simply leave it up to the mysterious will of the all-powerful sky faerie.

Actually, the stuff you're talking about is pretty much armchair-astronomy. The problem with astronomy (and all science in general) is that it didn't stop 2000 years ago, like Christianity did. By that I mean that Christianity had all the answers it needed contained in the introductory text. Science continues to evolve (pun most certainly intended), and will continue to for the forseeable future. We don't have all the answers, and have never claimed to. In fact, one of the basic tenets of science is that we don't have all the answers. Sadly, religious people simply avoid the questions with pithy aphorisms like "God works in mysterious ways."

It never fails to amuse me how people who are religious love to use the Big Bang argument as a wedge. The problem is, I have yet to meet someone who does this and, at the same time, has a deep understanding of the actual science behind it. Until you (and I mean "you" as in "religious people," not any specific individual) can sit down with pencil and paper and prove the physicists wrong, arguments like these would be better suited to the first year philosophy / astronomy / physics classes where they belong. No offense.

The biggest problem here is that Christians love to argue against science without understanding that science has nothing to do with disproving the existence of their god. Einstein felt that his theories more clearly showed the great glory of his all-powerful sky faerie. And he wasn't alone. Even Newton was a good Christian boy. Albiet most likely gay. So unwelcome in the church. Because gay people can't bring glory to the all-powerful sky faerie. Or something. My point is, what does it look like when the all-powerful sky faerie says "let there be light." Is it like a halogen desk lamp being turned on? Or does it look like an expansion wave of charged particles? Sorta like...

...the Big Bang.

See, you don't know. You assume that science and religion have to be mutually exclusive. And so Christians eschew any scientific theory that doesn't suit their ossified view of the world. And that's why we have things like bans on gay marriage, abortion doctors being murdered, etc., etc.... And arguments against the Big Bang.

It's ridiculous, really. Say what you want, but Christians have nothing over Scientologists, or any other cult that only listens to, and bases their view of the world on, what one individual says, without any regard for that grapefruit sized chunk of grey goo in their noggin. I don't have 100% faith in science, but I will say this for it over religion:

How'd that prayer work out for you during the Black Death? No? Shame, we're doing quite well on things like smallpox and polio over here in the science camp. And if you need a bit of help, we're doing fantastic stuff with the Black Death lately, too.