There's a long chain of events that led from the collapse of our local cloud of gas and dust to the evolution of life here on Earth. Exactly how each of these steps unfolded is still a bit of a mystery, but scientists know that a few atomic combinations were necessary: water, and organic compounds containing carbon. Dying stars are the source for this carbon, which they belch out, creating a kind of carbon soot. From there, this soot is blasted by intense radiation to create more than 100 different molecules, including fatty acids and simple sugars.