A small, soft space rock crashed on April 23, 2019 in Costa Rica. And it may have carried building blocks for life.
The washing machine-sized clay fireball broke on before landing. Local people found sharks scattered between two villages, La Palmera and Aguas Zarcas. And while meteorites are rising everywhere Earth, these sharps were special; the asteroid that spawned them was a soft remnant of the early solar system, made of the dust from the spinning nebula that would eventually form our solar system, formed into even older stars. And the meteorites that rained down from the event – collectively called Aguas Zarcas – belong to a rare class called carbon-like chondrites, which form in the small hours of the rising solar system and are typically full of carbon. This particular space rock contains complex carbon connections, probably inclusive amino acids (who participate in form proteins en DNA) and perhaps other, even more complex building blocks of life.
Related: How did life on Earth come about?
While other rocky pieces from the very early solar system were part of planets, these remained only intact and changed over time only by sunlight-driven chemical reactions that stimulated the creation of more and more complex chemical compounds.
An earlier meteor that exploded in 1969 over Murchison, Australia, had similar functions. Amino acids discovered in their clay, Joshua Sokol reported in Science, helped spread the idea life on Earth may have originated from chemicals supplied in meteorites. And like the Murchison meteorite, this Aguas Zarcas fragment contains dust from the ancient, former Milky Way, before our sun formed.
Studies of this new meteorite are not yet complete, Sokol wrote. But researchers are excited that they can explore it with modern techniques, in search of complex organic compounds – perhaps even proteins – – that even if they once existed in the Murchison meteorite, have long since disappeared, devastating in the atmosphere of the earth. (The Murchison meteorite was very similar to Aguas Zarcas, and if Aguas Zarcas contained proteins, then Murchison probably did well too, although the chance of detecting them was lost.) Although there is evidence of amino acids in this Aguas Zarcas- fragment not found anywhere else is Earth.
Aguas Zarcas shards can still offer the most pristine samples of the early solar system and pre-solar cloud. But landing as they did in the Costa Rican rainforest, Sokol reported, there is still the possibility of contamination.
Along the way, even more unpristing examples may be available. The Japanese Hayabusa2 probe, launched in 2014 with the aim of sampling the asteroid Ryugu, is already on its way back with Ryugu dust on board, a sample that may contain carbonaceous chondrite, Sokol noted. And in 2023, NASA will return its own samples of a similar asteroid, Bennu, which Sokol reported is likely related to Aguas Zarcas.
“These asteroid plots will be truly unobtrusive, and have never touched the atmosphere or sat on top of the rainforest ground,” Sokol wrote.
But for now, Aguas Zarcas is the best source of space-emitting carbon bonds available.
Originally published on Live Science.
