DNA from Space? Nucleobases from Ryugu and the origin of life
Let's take a break from going on and on about hominin fossils and talk a little biochemistry instead. I'm seeing (once again) big headlines talking about how five of the essential ingredients of life were found on asteroid Ryugu. I'm actually kind of impressed this time, since most of the headlines are actually pretty tame, except for a few headlines claiming "all the ingredients" for DNA or life have been found. Still, these sorts of discoveries get spun into some kind of support for models of the abiotic origin of life, that is, life spontaneously emerging from dead chemicals. As a biochemist by training, I got some strong opinions about that, so let's take a look. The Hayabusa 2 mission, run by the Japanese space agency JAXA, rendezvoused with an asteroid called 162173 Ryugu in the summer of 2018, after 42 months of travel from earth. Hayabusa 2 spent seventeen months observing the asteroid, then collected samples from the surface. Those samples arrived on ...