Tunga skyar
While the study authors didn't numerically calculate the impact of a shock wave that a "grazing" iron meteor of this size could produce, their estimates still suggest that such a wave would be powerful enough to flatten trees and damage the ground as the Tunguska event did, Pariev said in the email. Related: Crash! View Deal.
Meteor that blasted millions of trees in Siberia only 'grazed' Earth, new research says
However, some lingering questions about this scenario remain, said Mark Boslough, a research professor at the University of New Mexico and physicist with Los Alamos National Laboratory. But because of the meteor's mass and momentum , it didn't break up; it then exited the atmosphere and returned to space, the researchers reported. During its fiery passage, the meteor would lose some of its mass. By comparison, a meteor that exploded over Chelyabinsk, Russia, in February broke into fragments that were discovered within a week, Pariev said.
What if, the researchers questioned, the Tunguska meteor were made of iron rather than rock? That's something you'd expect to see after an explosion rather than a sonic boom, "even if it had been strong enough to blow trees over. Could a massive iron meteor "graze" Earth's atmosphere, approaching close enough to generate a powerful shock wave, then yank free of the planet's gravitational pull and escape without fragmenting?
She has reported on general science, covering climate change, paleontology, biology and space. To test that hypothesis, the scientists calculated en rymdsten som brinner upp när den kommer in i jordens atmosfär paths using computer models. A meteor that exploded before hitting the ground was thought by many to be the culprit. Prior studies have calculated the power of chock waves produced by meteors based on the object entering Earth's atmosphere at a very steep angle "and either hitting the ground or exploding in midair," Pariev said.
The findings were published online in the March issue of the journal Monthly Notices of the Royal Astronomical Society. Now, a grupp of researchers has proposed a solution to this long-standing puzzle: A large iron en rymdsten som brinner upp när den kommer in i jordens atmosfär hurtled toward Earth and came just close enough to generate a tremendous shock wave.
Known as the Tunguska event, the blast flattened more than 80 million trees in seconds, over an area spanning nearly square miles 2, square kilometers — but left no crater. What's more, the pattern of felled trees at the site is radial — emanating from a single point of tremendous energy release, he said. Related: Top 10 ways to destroy Earth. Related: Space-y Tales: The 5 strangest meteorites. Initial explanations for the blast included volcanic eruptions and mining accidents, according to NASA , but those claims were not supported by physical evidence.
Tunga skyar (feat. Helen Sjöholm)
Social Links Navigation. Originally published on Live Science. Other later suggestions were more far-fetched, such as a crashed UFO or a black hole collision with Earth — a study describing the black hole hypothesis was published in the journal Nature in and was soundly debunked in another Nature study published just a few months later. The most widely accepted scientific explanation is that a rocky asteroid or comet entered Earth's atmosphere and then disintegrated with a bang about 3 to 6 miles 5 to 10 km above the ground, Pariev told Live Science in an email.
They looked at objects that were as small as feet 50 meters across and as large as feet m in diameter. Objects were made of rock, ice or iron, and approached in a trajectory that brought them within 6 to 10 miles 10 to 15 km of Earth's surface. A new explanation for a massive blast over a fjärrstyrd Siberian forest in is even stranger than the mysterious incident itself. But iron shed by a meteor traveling at such speeds would have escaped as gas and plasma , oxidized in the atmosphere and then dispersed on the ground, becoming nearly indistinguishable from terrestrial iron oxides, according to the study.
Her videos about dinosaurs, astrophysics, biodiversity and evolution appear in museums and science centers worldwide, earning awards such as the CINE Golden Eagle and the Communicator Award of Excellence. Contact me with news and offers from other Future brands Receive email from us on behalf of our trusted partners or sponsors. However, a comet or asteroid would likely have left behind rocky fragments after blowing up, and no "smoking gun" remnants of a cosmic visitor have ever been found.
Boslough, who was not involved in the study, told Live Science in an email that if an object "skimmed through the atmosphere" and didn't blow up, the resulting shock wave would be significantly weaker than an explosion's blast wave. But the meteor then curved away from our planet without breaking up, its mass and momentum carrying it onward in its journey through space. In the case of the Tunguska meteor, the iron-rich space object could have entered Earth's atmosphere at a very shallow angle — about 9 to 12 degrees tangential to the surface.
It then would have grazed through the atmosphere, creating a shock wave at an höjd över havsnivån of around 6 to 10 miles 10 to 15 km above the ground, capable of flattening trees for hundreds of kilometers and scorching the surface. The scientists' calculations showed that space bodies made of rock and ice would completely disintegrate under the enormous pressures generated by their passage through the tropospheric altitudes.
On the morning of June 30, , the sky above Siberia flared so bright and hot that a witness standing dozens of kilometers from the site thought that his shirt had caught fire, said Vladimir Pariev, co-author of the new Tunguska study and a researcher with the P. Following the bright light, which lasted for about 1 minute, was an explosion that smashed windows and knocked people off their feet in a town more than 35 miles 60 km away, the BBC reported.
But such an explosion should have strewn the ground with rocky debris, which no one has ever found. Mindy Weisberger is an editor at Scholastic and a former Live Science channel editor and senior writer. Energy released by the blast was later estimated by scientists to be times greater than that of the atomic bomb dropped on Hiroshima in , according to NASA. Mindy Weisberger.