A small asteroid flew across the sky and burned up over the Kalahari Desert in Botswana in the summer of 2018, and scientists now suspect the space rock originated from Vesta, the world’s second largest asteroid. solar system…
Small asteroiddubbed 2018 LA, was first seen through a telescope at the University of Arizona’s Catalina Sky Survey and looked like a speck of light whistling through the stars. according to the SETI Institute…
“This is just the second time we’ve seen an asteroid in space before it crashed. land over land, ” SETI meteor astronomer Peter Jenniskens said in a statement. “The first was asteroid 2008 TC3 in Sudan 10 years earlier.”
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Just hours after being spotted, 2018 Los Angeles fell from the sky and burned up in the atmosphere over Botswana, turning into shiny fireball… Notably, the SkyMapper telescope at the Australian National University (ANU) captured the moments just before the rock broke through the Earth’s atmosphere, and CCTV footage captured the last moments of the explosive meteor impact in black and white.
“These last images before the asteroid entered Earth’s atmosphere were SkyMapper’s biggest contributions. They helped to pinpoint both the search area for meteorite fragments on Earth and the place of origin of the meteorite in space, ”said Christopher Onken, scientist for the ANU SkyMapper project. ANU said in a statement…
Based on available astronomical observations, an international team of scientists identified the area where the meteor likely disintegrated, scattering fragments of space rock onto the earth below; this region fell into the Kalahari Central Nature Reserve, a national park in the Kalahari Desert.
“The meteorite is named ‘Motopi Pan’ after a local watering hole,” Mohutsiva Gabadirwe, a geologist at the Botswana Institute of Geology (BGI) in Lobatz, said in a SETI statement.
Searching the park on several field expeditions, the team found 23 fragments of the Motopi Pan meteorite; They then analyzed isotopes or versions of elements with different numbers of neutrons in the meteorite pieces. These isotopes hint at the chemical composition and size of the original asteroid before it burst through the atmosphere.
Researchers determined that Los Angeles in 2018 originally had a diameter of about 5 feet (1.5 meters) and traveled in space for 22 to 23 million years before crashing on Earth. According to ANU, the rock moved at about 37,280 miles per hour (60,000 km / h) before entering the planet’s atmosphere.
Further analysis of the rock debris showed that they are very similar to another group of meteorites called Saricicek, which fell in Turkey in 2015.
Both sets of meteorites have been categorized as Howardite-Eucrite-Diogenite (HED) meteorites, which are the only meteorite class that dates back to Vesta, according to the American Museum of Natural History (AMNH). The eucrite chunks in the HED meteorites contain solidified lava from the surface of Vesta; diogenites contain minerals from rocks buried beneath the surface of the asteroid; and Howardites are a unique mixture of two other types of rocks, formed when objects collided with Vesta.
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“In general, we classified the material that was contained on asteroid 2018 LA as howardite, but some individual fragments had a greater affinity for diogenites and eucrites,” Jenniskens said. The asteroid formed as a breccia or a cemented mixture of individual pieces of rock originating from different parts of Vesta.
“The oldest known materials found in both the West and the meteorite are zircon grains that date back more than 4.5 billion years ago, during the early phase of the solar system,” Onken said. The authors found that the orbital path that Los Angeles traveled around Earth in 2018 also points to West as the asteroid’s point of origin.
Although both are HED meteorites, Motopi Pan and Saricichek differed in several ways. For example, the team calculated that material in both meteorites probably solidified on the surface of Vesta around 4.563 billion years ago, but the phosphate grains at Motopi Pan showed evidence that they melted in later history, while Saricichek did not have these marks. …
This hinted that Motopi Pan formed near the center of a large collision that occurred about 4.324 billion years ago, the team concluded. They suspect that this same event formed a giant dent, known as the Venenia Impact Basin, on the surface of Vesta.
“We now suspect that Pan Motopi was heated by the Venenia strike, while the subsequent Reasylvia strike, which came later and partially obscured the Venenia shock basin,“ scattered this material, ”Jenniskens said.
“As the team tracked the rock from space all the way to the impact site, they were able to calculate a very precise orbit that is consistent with the origin near Vesta, providing one of the best asteroid-meteorite connections we have,” Ashley King, planetary scientist at the Museum of Natural history that did not take part in the work, said The Guardian…
The team described their findings in a new study published in the journal Meteoritics and Planetary Science.
Originally published on Live Science.