and the Meteorite You Rode in On

A few entries back I talked about the symposium about life in the universe that I attended last week. One of the talks we heard was about the existence of minerals and molecules in space that are the precursors to the building blocks of life. These are things like amino acids, which are pivotal in the soup of life.

Well, news comes today that confirms the the idea that meteorites are very rich sources of amino acids. Given that meteorites rain down on Earth all the time (and have done so throughout our planet’s history, it’s pretty much a given that they were generous donors to the “primordial soup” from which life on Earth sprang a few billion years ago. Scientists at the Carnegie Institution of Washington have discovered high concentrations of amino acids in two meteorites; those levels are ten times higher than other previous measurements. (For those of you who’d like to see the science results, the scientists involved have uploaded a paper for your reading pleasure.)

Amino acids are the backbones of proteins, which themselves are the “stuff” of which life is made. That’s a very simplified version of the larger biochemical story. Essentially, you have to have proteins to get life, and while some amino acids undoubtedly simmered from the stew of stuff available on early Earth, it’s plausible to assume that some of them rode in from space on meteorites. Specifically, a type of meteorite known as CR Chondrite , which contain some of the oldest and most primitive organic materials dating back to the time of our solar system’s formation. (The image at left is a sample of the NWA 869 meteorite, which is a chondrite of a similar type to a CH.)

We’ve long known that comets, which come from the Oort Cloud and have peppered Earth throughout its history, also carry organics and have long been thought of as carriers of such materials. Finding amino acids that contributed to Earth’s “soup of life” in meteorites is another step toward understanding the conditions and materials that formed the solar system