Fri, Apr 21, 2017 - Page 6 News List

Close call: When large asteroids whisk past Earth

AFP, PARIS

Images of asteroid 2014-JO25 generated by NASA’s Goldstone Solar System Radar in California’s Mojave Desert are pictured in a composite image released on Tuesday.

Photo: Reuters

A peanut-shaped asteroid 1.3km across streaked past Earth on Wednesday, giving astronomers a rare chance to check out a big space rock up close, but not too close.

Dubbed 2014-JO25, the asteroid came nearest at 12:20 GMT and is now hurtling away from the center of our solar system, said Ian Carnelli, an astronomer at the European Space Agency.

“It does not represent a danger to our planet,” Carnelli said, adding that the asteroid passed within 1.8 million kilometers of Earth — about four times the distance to the moon.

The Arecibo observatory in Puerto Rico — which has one of the world’s biggest radio telescopes — captured the first images of 2014-JO25, showing an object that is likely “two large asteroids that fused together.”

The space projectile remained visible to onlookers equipped with a telescope in the northern hemisphere on Wednesday night.

You might not see them, but space rocks whizz above our heads all the time.

Patrick Michel, an astronomer at the Cote d’Azur Observatory, estimates that an average of 10,000 to 100,000 tonnes of spatial material come into our general neighborhood each year, but large asteroids passing this close to Earth remain a rarity.

“The next one will pass by in 2027, a 800m-long object that will come within” one Earth-to-moon distance, Michel said.

The last time 2014-JO25 was in our vicinity was 400 years ago and its next close encounter with Earth will not happen until sometime after 2600.

POTENTIALLY HAZARDOUS

Asteroid 2014-JO25 does not represent an immediate danger, but it does fall within the category of “potentially hazardous asteroids” that astronomers monitor for safety, Pascal Descamps, an astronomer at the Paris Observatory, said by telephone.

Any space rock at least 1km across that travels within 7 million kilometers of Earth qualifies.

The good news is that scientists have identified at least 90 percent of these flying hazards within our solar system.

“There isn’t a single one that threatens us in the short term, meaning in the next few centuries,” Michel said. “There are thousands of asteroids larger than 1km. The frequency with which they could hit us is once every 500,000 years, so we are facing a risk that is very low.”

Many sizeable asteroids have crashed into Earth or exploded in our atmosphere, leaving behind massive craters — and clues as to their composition.

More than 60,000 years ago, a 30m rock crashed into what is today Arizona and 65 million years ago, an even bigger asteroid slammed into Earth a little further south, which scientists believe led to the extinction of non-avian dinosaurs.

A 1km asteroid hitting our planet today would be like “a million Hiroshima bombs” and trigger the extinction of roughly a quarter of all the Earth’s species, Michel said.

A 10km object ... would provoke the extinction of our species,” he added.

TEST PLANNED

To prevent such a catastrophe, a team of astronomers from NASA and the European Space Agency have drawn up plans for a live test in space — deviating a potentially deadly asteroid.

An self-guided 400kg satellite — hurtling at 6kps — would target an approaching asteroid.

The objective would not be to destroy the object, but to deflect it, since fragments could then crash into Earth.

A target has been selected, but so far funding has not been approved.

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