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Asteroids Are Falling On Earth’s Surface Twice As Often: Study

This enhanced impact rate poses a threat for the next mass extinction event.

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Asteroids
This Dec. 29, 1968, photo made available by NASA shows craters on the moon. For the past 290 million years, giant rocks from space have been crashing into Earth more than twice as often as they did in the previous 700 million years, according to a new study. VOA

Giant rocks from space are falling from the sky more than they used to, but don’t worry.

For the past 290 million years, large asteroids have been crashing into Earth more than twice as often as they did in the previous 700 million years, according to a new study in Thursday’s journal Science.

But no need to cast a wary glance up. Asteroids still only smack Earth on average every million or few million years, even with the increased crash rate. NASA’s list of potential big space rock crashes shows no pending major threats. The biggest known risk is a 4,200-foot (1.3-km) wide asteroid with a 99.988 percent chance that it will miss Earth when it whizzes very near here in 861 years.

Tell that to the dinosaurs. Most scientists think dinosaurs and a lot of other species went extinct after a huge space rock crashed into Central America about 65 million years ago.

Earth, Asteroids
Taurids meteor shower lights up the sky. The risk of asteroids hitting the Earth has grown over the years. Wikimedia

“It’s just a game of probabilities,” said study lead author Sara Mazrouei, a University of Toronto planetary scientist. “These events are still rare and far between that I’m not too worried about it.”

Mazrouei and colleagues in the United Kingdom and United States compiled a list of impact craters on Earth and the moon that were larger than 12 miles (20 km) wide and came up with the dates of them. It takes a space rock that’s half a mile (800 meters) wide to create holes that big.

The team counted 29 craters that were no older than 290 million years and nine between 291 million years and 650 million years old.

But we can see relatively few big craters on Earth because the planet is more than 70 percent ocean and past glaciers smoothed out some holes, said University of Toronto planetary scientist Rebecca Ghent, a study co-author.

Earth, Asteroids
These rocks were rare survivors from a very different time on Earth. Pixabay

Extrapolating for what can’t be seen brings the total to about 260 space crashes on Earth in the last 290 million years. Adding in other factors, the science team determined that the current space crash rate is 2.6 times more than the previous 700 million years.

Craters older than 650 million years are mostly wiped off on Earth by glacial forces so the scientists used impact craters on the nearby moon as a stand-in for holes between 650 million and 1 billion years old. The moon is a good guide for estimating Earth crashes, because it is close enough to be in the same bombardment path and its craters last longer.

Mixed reactions

So what happened nearly 300 million years ago?

“Perhaps an asteroid family was broken up in the asteroid belt,” Mazrouei speculated. The space rocks then headed toward the Earth and moon, and the planet got slightly more because it is a bigger target and it has higher gravity, Ghent said.

Oldest known asteroid family
An asteroid family. Wikimedia

Outside scientists are split about the research. Jay Melosh at Purdue said he found the number of craters too small to come to a reasonable conclusion, but Harvard’s Avi Loeb said the case was convincing.

Also Read: Newly Discovered Super-Earth Exoplanet May Sustain Primitive Life

Humans might not have emerged without mass extinctions from space rocks about 250 million and 65 million years ago, Loeb said in an email, adding, “but this enhanced impact rate poses a threat for the next mass extinction event, which we should watch for and attempt to avoid with the aid of technology.”

“This demonstrates how arbitrary and fragile human life is,” Loeb wrote. (VOA)

Next Story

SpaceX Plans To Send NASA Astronauts To Space in Q2 This Year

As part of the test on Sunday, SpaceX configured Crew Dragon to trigger a launch escape about 1.5 minutes after liftoff

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NASA
It took a lot of work between NASA and SpaceX to get to this point. Pixabay

After NASA and SpaceX successfully completed a launch escape demonstration of the company’s Crew Dragon spacecraft and Falcon 9 rocket, Elon Musk said that his aerospace company aims to send NASA astronauts to space between April and June this year.

This was the final major flight test of the spacecraft before it begins carrying astronauts to the International Space Station (ISS) under NASA’s Commercial Crew Programme, the US space agency said in a statement on Sunday.

With this test now complete, the next big flight of the Crew Dragon will have people on board: NASA astronauts Bob Behnken and Doug Hurley.

“We’re highly confident that the hardware will be ready in Q1, most likely at the end of February but no later than March. And we think it appears probable that the first crewed launch would occur in the second quarter,” said Musk after the successful uncrewed test of its Crew Dragon capsule’s in-flight launch escape capabilities.

Musk said that if all goes well, the first crewed flight on the Crew Dragon could take place in the second quarter of this year.

“This critical flight test puts us on the cusp of returning the capability to launch astronauts in American spacecraft on American rockets from American soil,” said NASA Administrator Jim Bridenstine. “We are thrilled with the progress NASA’s Commercial Crew Programme is making and look forward to the next milestone for Crew Dragon.”

As part of the test on Sunday, SpaceX configured Crew Dragon to trigger a launch escape about 1.5 minutes after liftoff. All major functions were executed, including separation, engine firings, parachute deployment and landing. Crew Dragon splashed down at 10:38 am just off the Florida coast in the Atlantic Ocean.

“As far as we can tell thus far, it’s a picture perfect mission. It went as well as one can possibly expect,” said Musk. “This is a reflection of the dedication and hard work of the SpaceX and NASA teams to achieve this goal. Obviously, I’m super fired up. This is great.”

NASA
After NASA and SpaceX successfully completed a launch escape demonstration of the company’s Crew Dragon spacecraft and Falcon 9 rocket, Elon Musk said that his aerospace company aims to send NASA astronauts to space between April and June this year. Wikimedia Commons

Prior to the flight test, teams completed launch day procedures for the first crewed flight test, from suit-up to launch pad operations. The joint teams now will begin the full data reviews that need to be completed prior to NASA astronauts flying the system during SpaceX’s Demo-2 mission. “The past few days have been an incredible experience for us,” said astronaut Doug Hurley.

ALSO READ: Bollywood Actress Bhumi Pednekar Urges People To Avoid Single Use Of Plastics

“Today, we watched the demonstration of a system that we hope to never use, but can save lives if we ever do. It took a lot of work between NASA and SpaceX to get to this point, and we can’t wait to take a ride to the space station soon,” he said in the NASA statement. (IANS)