It's unlikely that the process produced Titanians, but experiments simulating the chemistry of the dense air on Saturn's biggest moon have yielded some of the basic buildings blocks of life. Scientists described how they used radio-frequency radiation—a more convenient substitute for ultraviolet sunlight—to turn methane, nitrogen, and carbon monoxide (the main constituents of Titan's atmosphere) into glycine and alanine, the two smallest amino acids. The experiments also produced cytosine, adenine, thymine, and guanine, the four most basic components of DNA. And they created uracil, a precursor of RNA. The researchers said that because they achieved the reactions without the presence of liquid water, it's possible life could have sprung forth on Earth not in the seas, as commonly assumed, but perhaps in the planet's early atmosphere—a considerably thinner version of the fog enveloping Titan today.