Ancient meteorites zipping through outer space might have been mobile factories that pumped out the molecules necessary for life on Earth—and maybe elsewhere, too.
Chondrites, as they’re called, are just one class of meteorite that might have delivered some of the first prebiotic molecules believed play a key role in the origin of life. Just two conditions might have been necessary to produce those molecules, researchers say: that the meteorites were exposed to solar wind and that they carried the compound formamide, a relatively simple organic compound that’s common in space and contains oxygen and nitrogen. The team, whose members hail from Italy and Russia, published their results this week in the Proceedings of the National Academy of Sciences.
The team took samples from four different classes of meteorites and added them to liquid formamide at low, space-like temperatures. Then to simulate the presence of solar wind, they shot a proton laser beam at the meteorite mixture. This combination of steps created nucleobases, carboxylic acids, sugars, amino acids, and four nucleosides in the mixture. These are some of the building blocks of RNA and DNA.
Galaxy centers and stellar nurseries are home to large quantities of formamide, which scientists have been studying for a long time. They’ve suspected that formamide had some role in engendering life, but they hadn’t yet determined a plausible mechanism.
Here’s Anthony King, writing for Chemistry World:
Previous research hypothesised such reactions occurring on Earth, powered by meteorite bombardment, but this work raises the prospect of reactions in space facilitating life on Earth or other planets. This scenario suggests that if life formed on other planets it might share similarities with that on Earth.
Lucy Ziurys, an astrochemist at the University of Arizona, U.S., previously estimated that in interstellar space 10-10 molecules of formamide exist for every hydrogen molecule, making it fairly abundant by astronomical standards. “We did some back-of-an-envelope calculations and millimolar quantities could be delivered to a planet surface on carbonaceous chondrites,” she says. With greater frequency of bombardment, as hypothesised for Earth around 3.5 billion years ago, amounts would go up.
In other words, massive quantities of the seeds of life may have been peppered throughout the universe long ago. If these conditions occurred near distant planets similar to own, life may have sprung there, too—and would probably not look too strange or unfamiliar.