Scientists have discovered pieces of a meteorite that fell near Berlin just after midnight on January 21. This is a rare discovery, from an asteroid that was only identified before it entered Earth’s atmosphere. Only a few events like this in the past have allowed astronomers to trace the origin of rocks that came from the solar system.
Initial analysis of the fragments suggests something equally rare. The meteorite is an aubrite, a class of unknown origin that some scientists argue may be a piece of the planet Mercury. They are so rare that there were only about 80 aubrite meteorites out of about 70,000 collected on Earth before last month’s event.
“This is really interesting,” said Sara Russell, a meteorite expert at the Natural History Museum in London. “There is very little aubrite.”
The meteorite (or rather meteorite fragment) was initially seen by Krisztián Sárneczky, an astronomer from Hungary, three hours before entering the Earth’s atmosphere. A network of cameras tracked the rock as it fell near Ribbeck, a village outside Berlin. Estimates suggest that the stone is very small, less than three feet across. But the rock still produced bright flashes that were observed by cameras in many parts of Europe.
Immediately after hearing news of the meteorite fall, Peter Jenniskens, an astronomer from the SETI Institute in California, bought a plane ticket.
“On Saturday afternoon I heard it,” he said. “On Saturday evening I was on a plane to Berlin.”
During his nine-hour layover in Newark, Dr. Jenniskens calculated where meteorite fragments might be found so that when he landed early Monday morning, he and nearly two dozen other students and volunteers could immediately begin searching for fragments.
For several days they searched the fields around Ribbeck. “We couldn’t find anything,” he said.
But on Thursday, January 25, a team of meteor hunters from Poland announced that they had found the first piece of a meteorite. “They can show us what to look for,” says Dr. Jenniskens. The meteorite is not black, as would be expected after passing through the atmosphere, but bright, like rocks on earth.
With this information, in just two hours a member of Dr. Jenniskens, a student at Freie Universität Berlin named Dominik Dieter, discovered a meteorite above the ground. More fragments were soon discovered.
“This is amazing,” said Dr. Jenniskens. “We found more than 20 fragments.”
Researchers at the Natural History Museum in Berlin analyzed the minerals in the fragments using an electron microprobe. This indicates that the rock appears to be aubrite. This is the first time a meteorite of this kind has been verifiably collected.
The origin of the aubrites, named after the French town of Aubres near where they were first discovered, remains mysterious, as their composition does not match any known meteorite sources in the solar system. Some studies have suggested that they are fragments of the planet Mercury, but not all scientists support that origin story.
If aubrites originate directly from Mercury, 2024 BX1 should originate from within the solar system. However, tracing back its path, it seems that the asteroid’s initial orbit was much wider and outside Earth’s orbit.
“Therefore, this object could not have come directly from Mercury,” said Marc Fries, a planetary scientist at NASA’s Johnson Space Center.
It is possible, however, that aubrites were thrown from Mercury far into the past into the asteroid belt between Mars and Jupiter, forming a group of so-called E-type asteroids. The orbit of 2024 BX1 does not completely rule out this idea, although Dr. Fries remains skeptical.
But whatever its origin, the 2024 BX1 fragment will prove scientifically interesting. “I believe it will be a priority to find out its composition and how it compares with other meteorites,” said Dr. Russell.
Tracking asteroids this small before they enter Earth’s atmosphere is also important for protecting the planet from asteroids. Davide Farnocchia, from NASA’s Center for Near-Earth Object Studies, said small objects from space often go undetected, but can cause problems for humans on land, such as the 65-foot-diameter Chelyabinsk meteorite that exploded in Russia in 2013 and injured hundreds of people. Knowing their path in advance can give people time to reach safety.
“If we could have given warning, no one would have been hurt,” he said.
2024-02-10 10:23:56
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