One evening in April, 2019, the skies above La Palmera, a village in northern Costa Rica, began to glow as a motorcycle-sized meteorite broke aside and scattered chunks of scorching house rock over the rain forest beneath. It was simply one in every of 1000’s of meteorites that hit the Earth yearly, however this explicit one, later dubbed Aguas Zarcas, caused a frenzy among experts. To the untrained eye, its fragments appear to be unassuming grey rock. However packed inside are a menagerie of natural molecules and house mud that predate the delivery of our photo voltaic system.
Aguas Zarcas is among the many most pristine examples ever found of a category of meteorites often called carbonaceous chondrites. It’s a deeply unsexy title, however these historic house rocks are like time machines that present home windows into the universe because it existed billions of years in the past. They’re distinctive geological information that element the formation of amino acids in house, which some scientists imagine might have been the abiotic grist that kick-started 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 position in Meteorite, a brand new ebook by the College of Bristol cosmochemist Tim Gregory. However these weird extraterrestrial guests are simply one in every of a seemingly limitless number of strange house rocks, and Gregory’s ardour for his topic drips from each web page. Meteorite is a mixture of science and historical past that’s stuffed with anecdotes of shut calls and joyful accidents. Gregory strikes a superb steadiness between onerous science and the hard-to-believe, however he guarantees every thing between the covers is true.
WIRED caught up with Gregory at dwelling in Nottingham, England, to study extra in regards to the ebook and why the most effective place to discover a meteorite is on the finish of the Earth. The next interview has been frivolously edited for readability and size.
WIRED: You’re employed as a ‘cosmochemist.’ What’s cosmochemistry, and the way did you get into it?
Gregory: I’ve all the time cherished rocks, and I’ve all the time cherished house, as effectively. I found a few years into my undergraduate diploma that there is a self-discipline that mixes each of them—rocks and house—and that is cosmochemistry. It makes use of the identical instruments as geochemistry, but it surely simply occurs to be on rocks from outer house as a substitute of the Earth.
What makes house rocks completely different from Earth rocks?
There are some things that distinguish meteorites from Earth rocks. The obvious one is their age. Nearly all meteorites we’ve found come from asteroids, they usually cooled down in a short time after they shaped. The Earth has an inner warmth engine by means of the decay of radioactive isotopes that’s nonetheless powering volcanic and tectonic processes. So the Earth continues to be geologically energetic, whereas the geological processes on these asteroids was very short-lived. So the rocks that come from these locations, the meteorites, have not modified a lot in any respect within the final 4 and a half billion years. They’re far older than the oldest Earth rocks.
How are you going to inform a meteorite from some other rock on Earth except you see it fall to the bottom?
Meteorites look precisely like Earth rocks, so we’ve to enter the chemistry and take a look at their isotope composition. There are very refined chemical variations that kind of show their extraterrestrial origin. They arrive from basically completely different worlds, which inherited a barely completely different mix of chemical substances once they shaped. With the meteorites, there isn’t any approach that you could find that kind of chemical fingerprint on Earth except it got here from one other world.
The place do scientists discover their meteorites?
We have about 60,000 meteorites within the worldwide assortment, and most of them got here from Antarctica. There are just a few causes for that. The primary one is de facto apparent: Typically, meteorites are actually darkish once they land on the floor, and ice is white. In order that they stand out like a sore thumb on the ice sheet.