One night time in April, 2019, the skies above La Palmera, a village in northern Costa Rica, began to glow as a bike-sized meteorite broke aside and scattered chunks of sizzling area rock over the rain forest under. It was simply certainly one of 1000’s of meteorites that hit the Earth yearly, however this specific one, later dubbed Aguas Zarcas, caused a frenzy among experts. To the untrained eye, its fragments appear to be unassuming grey rock. But packed inside are a menagerie of natural molecules and area mud that predate the beginning of our photo voltaic system.
Aguas Zarcas is among the many most pristine examples ever found of a class of meteorites identified as carbonaceous chondrites. It’s a deeply unsexy identify, however these historic area rocks are like time machines that present home windows into the universe as it existed billions of years in the past. They’re distinctive geological data that element the formation of amino acids in area, which some scientists consider could have been the abiotic grist that kick-began the evolution of life on Earth. They’re a rarity amongst rarities, prized by collectors and scientists, and are sometimes worth more than their equivalent weight in gold.
Carbonaceous chondrites play a starring function in Meteorite, a new e book by the University of Bristol cosmochemist Tim Gregory. But these weird extraterrestrial guests are simply certainly one of a seemingly infinite number of bizarre and fantastic area rocks, and Gregory’s ardour for his topic drips from each web page. Meteorite is a mixture of science and historical past that’s crammed with anecdotes of shut calls and pleased accidents. Gregory strikes a good stability between arduous science and the hard-to-believe, however he guarantees every thing between the covers is true.
WIRED caught up with Gregory at residence in Nottingham, England, to be taught extra concerning the e book and why the perfect place to discover a meteorite is on the finish of the Earth. The following interview has been frivolously edited for readability and size.
WIRED: You work as a ‘cosmochemist.’ What is cosmochemistry, and how did you get into it?
Gregory: I’ve all the time liked rocks, and I’ve all the time liked area, as properly. I found a couple of years into my undergraduate diploma that there is a self-discipline that mixes each of them—rocks and area—and that is cosmochemistry. It makes use of the identical instruments as geochemistry, but it surely simply occurs to be on rocks from outer area as an alternative of the Earth.
What makes area rocks totally different from Earth rocks?
There are a few issues that distinguish meteorites from Earth rocks. The most evident one is their age. Almost all meteorites we’ve found come from asteroids, and they cooled down in a short time after they fashioned. The Earth has an inside warmth engine by the decay of radioactive isotopes that is nonetheless powering volcanic and tectonic processes. So the Earth is nonetheless geologically lively, whereas the geological processes on these asteroids was very quick-lived. So the rocks that come from these locations, the meteorites, have not modified a lot in any respect in the final 4 and a half billion years. They’re far older than the oldest Earth rocks.
How are you able to inform a meteorite from another rock on Earth except you see it fall to the bottom?
Meteorites look precisely like Earth rocks, so we now have to go into the chemistry and have a look at their isotope composition. There are very delicate chemical variations that type of show their extraterrestrial origin. They come from essentially totally different worlds, which inherited a barely totally different mix of chemical compounds once they fashioned. With the meteorites, there is no means that you could find that type of chemical fingerprint on Earth except it got here from one other world.
Where do scientists discover their meteorites?
We’ve bought about 60,000 meteorites in the worldwide assortment, and most of them got here from Antarctica. There are a few causes for that. The first one is actually apparent: Generally, meteorites are actually darkish once they land on the floor, and ice is white. So they stand out like a sore thumb on the ice sheet.