Bold feels from & # 39; space are falling out & # 39; heaven as it is present, but do not worry.
For the past 290 million years, large asteroids in & # 39; are more than twice as often as in & # 39; a previous 700 million years, according to a new study in the journal Science.
But no need for a lower glance. Asteroids are still only a million years old as the previous earth tastes, even with the increased lap. NASA's list of potential large space surpluses does not show great urge. The biggest known risk is a 4,200-kilometer-wide asteroid with a 99,988 percent chance of missing the ice if it is a heavy in 861 years.
Tell that to the dinosaurs. Most scientists believe that dinosaurs and many other species have died out after a tremendous space that crashed in Central America about 65 million years ago.
"It is only a game of whiteness," said student lead author Sara Mazrouei, a university of the Toronto planetarium scientist. "These events are still rare and further between me not trying."
Mazrouei and colleague's in the UK and the United States gathered a list of earth-based craters and the month that was greater than 12 kilometers (20 km) wide and came with their dates. The namesake of a space breeder that is a mile (800 meters) wide to make holes that are large.
The team has 29 craters that are no older than 290 million years and nine between 291 million years and 650 million years old.
But we can see relatively a few large craters on earth, because the planet is more than 70 percent in the ocean and the past glaciers draw some sounds, says University of Toronto, planetary scientist Rebecca Gent, in student co-author.
Extrapolation for what is not seen brings the total in the last 290 million years to approximately 260 space traffic on Earth. Adding to other factors has determined the science team that current space development is 2.6 times more than the previous 700 million years.
Crater older than 650 million years are usually deviated from earth by vigorous forces, so scientists use influx craters at & nbsp; a northern month as a stand-in for gats between 650 million and 1 billion years old. The month is a good guide to the destruction of earthly forces, because it is close enough in the same bombing and its craters last longer.
So what was 300 million years ago?
"Maybe an asteroid family was printed in the asteroid," Mazrouei speaks. The space bikes then went to the earth and the month, and the planet got a bit more because it was a bigger goal and it has higher gravity, said Ghent.
Outside scholars are split over the research. Jay Melosh at Purdue said the number of craters was too small to reach a reasonable conclusion, but Harvard's Avi Loeb said the case was convincing.
People may not have originated without masses of romances about 250 million and 65 million years ago, said Loeb in an email, "but this reinforced effect has a threat to the next mass loss event," ; we need to look and try ahead with technology. "
"Knowing how arbitrary and fragile human life is," Loeb wrote.