Scientistshave figured out why rocks, despite brutal heating, survive impacts to the earth's surface as meteorites.
"Most of our meteorites fall from rocks the size of grapefruits into small cars," says lead author and meteor astronomer at the SETI Institute and his NASA Ames Research Center. Peter his Jeniskens said.
"Rocks this large don't rotate fast enough to dissipate heat during the short phase of a meteor. There is now evidence that the underside remains on the ground."
Research uncovered this secret with the help of 2008 TC3.Discovered in 2008, he is a 6-meter asteroid that scientists tracked for more than 20 hours before hitting Earth's atmosphere. , created a bright meteor that collapsed in Sudan's Nubian Desert, resulting in a meteorite shower.
"In a series of dedicated search campaigns, students discovered more than 600 of his meteorites, some the size of a fist, others the size of a thumbnail." There were some,” said his professor Muawia Shaddad of the University of Khartoum. "For each meteorite, we recorded where it was found."
The researchers were surprised to find that the fist-sized meteorites were more spread out than the smaller ones.
2008 TC3 models show how asteroids melt and break apart, and that asteroids have a near-vacuum wake in the atmosphere. suggests. The first debris left the side of the asteroid and fell at a relatively low speed.
When the smallest meteorites fell to Earth, friction in the atmosphere prevented them from reaching the surface, but larger asteroids survived the journey.
"We reached a point where the front part of the asteroid melted more and more, and the surviving parts of the rear and lower rear part of the asteroid suddenly collapsed and split into many pieces," Robertson said. "The shape of the asteroid is the reason why Bottomback survived so long," Dr. Jenniskens added. They concluded that these fragments remained relatively large all the way to the ground.
Various types of meteorites were randomly scattered on the ground, but scientists know that cosmic rays in space can cause low-level activity. This is especially true on the surface of meteorites.
"The radioactivity is a good indication that the meteorite did not come from a better shielded interior," said Dr Jeniskens. I know it came from."
