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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

Cosmochemistry in Action

It’s pretty common knowledge in astronomy these days that planets grow from seeds hidden in clouds of gas and dust around other stars. Thats how our solar system got started a few billion years ago, and studying how it happens elsewhere helps us understand the birth of our own planet. But, the big question is always, “What about life?”

The Spitzer Space Telescope has been peering into clouds of gas and dust enshrouding nearby stars, and discovering the seeds of life. What are those seeds? Organic molecules (in the form of gases) and water vapor, to name a couple.

Two scientists who use SST, John Carr of the Naval Research Laboratory, and Joan Najita of the National Optical Astronomy Observatory (in Tucson, Arizona), used Spitzer’s infrared spectrograph to measure and analyze the chemical elements in a protoplanetary disk around a young star called AA Tauri. It’s less than a million years old and is pretty typical of young stars that have the cosmochemical seeds of life scattered around them in dense, dusty disks.

Other scientists are using Spitzer to look for water molecules in these same types of disks. And, they’re finding them.

This is important work, folks. Water and organics are two of the big three things you need to form life. But, before we get carried away and start thinking of little green beings from AA Tauri, keep in mind that the planets have to form first. Then the life will come (if all the conditions are good for it). It’s a big deal right now to find these materials in places other than our own solar system. It means the conditions for planets like Earth to form are out there. And, the existence of organics and water tell us that some billions of years from now, life might exist on planets around these stars. Visit the Spitzer news announcements for more background on this new set of findings.

The Spacewriter's Ramblings

It’s Raining Primordial Soup

and the Meteorite You Rode in On

The Seeds of Life

Cosmochemistry in Action

Exploring Science and the Cosmos