I'll let Napalm give a more professional answer, but to my knowledge the most widely accepted theory is that after some of the first generation stars went supernova, the elements that were created in the explosion went on to accrete (or "clump together") into other stars and, planets, etc. and life is a procreation of this process.
We don't know exactly, but there are some promising theories and research out there.
They teach sex education in America, right? You have one half of a DNA molecule from the father in the sperm and another half from the mother in the egg. Once a sperm reaches the egg, the strands fuse into a complete DNA molecule. This DNA "instructs" the fertilised egg to start multiplying itself, and thus, an embryo is formed.
That's not how life itself began, but it's worth mentioning because it explains another common question (namely, how did the planets form?), and it's how the materials for life got here. Originally most of the matter in the Universe was just hydrogen and helium, but in supernovae, heavier elements are formed (due to their tremendous energy). Some of the material from a supernova coalesces into a new star due to gravity, and from there, leftover material slowly "clumps together" into planets, comets, etc. So eventually, you've got a planet and the material which would eventually form life. How non-living matter went to living matter (abiogenesis) like that is still a mystery, but that doesn't mean we'll never figure it out.
This is precisely what I was aiming to explain, my apologies. Like you say, the origin of life itself isn't wholly known (yet).
I would presume you'd need to know organic chemistry and geology (particularly Earth's early geological history).
An invisible force that overpowers everything else in the universe called "gravity"? Come on.
First take a look at Tyler's response to you. Also note that Napalm responded and explained Tyler's original response more correctly.
