Scientists have found pieces of a meteorite that fell near Berlin shortly after midnight on January 21. It is a rare find, of an asteroid that was identified just before entering the Earth’s atmosphere. Only a handful of such events in the recent past have allowed astronomers to trace the origin of an incoming rock into the solar system.
The first analyzes of the fragments have shown something equally strange. The meteorite is an aubrite, a type of unknown origin that some scientists believe may be fragments of the planet Mercury. They are so rare that they made up only 80 of the approximately 70,000 meteorites that were collected on Earth before last month’s event.
“It’s really exciting,” said Sara Russell, a meteorite expert at the Natural History Museum in London. “There are very, very few aubrites.”
The asteroid that became a meteorite (or rather meteorite fragments) was initially discovered by Krisztián Sárneczky, a Hungarian astronomer, three hours before it impacted the Earth’s atmosphere. A network of cameras tracked the incoming rock, 2024 BX1, when it fell near Ribbeck, a town on the outskirts of Berlin. Estimates suggest that the rock was small, less than a meter in size. It still produced a bright flash that was captured by cameras in many parts of Europe.
As soon as he heard the news of the meteorite fall, Peter Jenniskens, an astronomer at the SETI Institute In California, I bought a plane ticket.
“On Saturday afternoon I found out,” he said. “On Saturday afternoon I was on a plane to Berlin.”
During a nine-hour layover in Newark, Dr. Jenniskens estimated where fragments of the meteorite might be found so that when he landed early Monday morning, he and nearly two dozen students and volunteers could begin searching for fragments immediately.
For days they roamed the fields around Ribbeck. “We couldn’t find anything,” she said.
But that Thursday, January 25, a Polish team of meteorite hunters announced that they had found the first piece of the meteorite. “They could show us what to look for,” Dr. Jenniskens said. The meteorites were not black, as expected from their passage through the atmosphere, but light, like terrestrial rocks.
With this information, in just two hours a member of Dr. Jenniskens’ team, a Freie Universität Berlin student named Dominik Dieter, found a meteorite just above the ground. More were quickly detected.
“It was amazing,” Dr. Jenniskens said. “We found more than 20 fragments.”
Researchers at the Natural History Museum in Berlin analyzed the minerals in the fragments using an electron microprobe. That revealed that the rocks appeared to be aubrite. It was the first time meteorites of this type had been collected in a tracked fall.
The source of the aubrites, named after the French town of Aubres near where they were first found, remains a mystery, as their composition does not match other known sources of meteorites in the solar system. Some research has suggested that they are fragments of the planet Mercury, but not all scientists support that origin story.
If the aubrites came directly from Mercury, 2024 BX1 should have originated in the inner solar system. However, by tracing its trajectory, it appears that the asteroid’s initial orbit was much wider and outside Earth’s orbit.
“Therefore, this object could not have come to us directly from Mercury,” said Marc Fries, a planetary scientist at NASA’s Johnson Space Center.
However, it is possible that aubrites were ejected from Mercury long ago into the asteroid belt between Mars and Jupiter, forming a group called E-type asteroids. The orbit of 2024 BX1 does not completely rule out this idea, although Dr. Fries remains skeptical.
Whatever their origin, the fragments of 2024 BX1 will prove scientifically fascinating. “I’m sure it will be a priority to find out what its composition is and how it compares to other meteorites,” Dr Russell said.
Tracking asteroids as small as this one before they collide with Earth’s atmosphere is also crucial to defending the planet from asteroids. Davide Farnocchia of NASA’s Center for Near-Earth Object Studies said smaller objects in space go unnoticed all the time, but can pose problems for people on the ground, like the 65-foot-wide Chelyabinsk meteor which exploded over Russia in 2013 and caused damage. hundreds of people. Knowing the trajectories in advance could give people time to reach a safe place.
“If a warning could be sent, no one would be hurt,” he said.