Close call: When asteroids whisk past Earth

April 19, 2017
This NASA image obtained April 19, 2017 shows a movie of asteroid 2014-JO25 generated using radar data collected by NASA's Goldstone Solar System Radar in California's Mojave Desert

A peanut-shaped asteroid 1.3 kilometres (3,280 feet) 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 came nearest at 12:20 GMT and is now hurtling away from the centre of our solar system, said Ian Carnelli, an astronomer from the European Space Agency (ESA).

"It does not represent a danger to our planet," Carnelli told AFP, noting that the asteroid passed within 1.8 million kilometres (1.1 million miles) 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 2014 JO25's first images, showing an object that is likely "two large asteroids that fused together".

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

Herewith, a little primer on near-Earth asteroids and the danger they pose (or not).

How common?

You may 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 tons of spatial material come into our general neighbourhood each year.

But large asteroids passing this close to Earth remain a rarity.

"The next one will pass by in 2027, a 800-metre long object that will come within" one Earth-to-the-Moon distance, he said.

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

How dangerous?

2014-JO25 does not represent an immediate danger. But it does fall within the category of "" that astronomers monitor for safety, Pascal Descamps, an at the Paris Observatory told AFP by phone.

Any space rock at least one kilometre (0.6 miles) across that travels within 7 million kilometres (4.3 million miles) 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 one kilometre," he added. "The frequency with which they could hit us is once every 500,000 years, so we are facing a risk that is very low."

A knock-out blow

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 30-metre (98-foot) rock crashed into what is today Arizona.

And 65 million years ago, an even bigger asteroid slammed into Earth a little further south, leading to the extinction of non-avian dinosaurs.

A one-kilometre asteroid hitting our planet today would be like "a million Hiroshima bombs," Michel said, and trigger the extinction of roughly a quarter of all species.

"A 10-kilometre object... would provoke the extinction of our species," he added.

What can be done?

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 : deviating a potentially deadly asteroid.

An self-guided 400-kilo satellite—hurtling at six kilometres per second—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.

So far, however, funding has not been approved.

Explore further: Big space rock to streak past Earth on Wednesday

Related Stories

Asteroid to fly safely past Earth on April 19

April 7, 2017

A relatively large near-Earth asteroid discovered nearly three years ago will fly safely past Earth on April 19 at a distance of about 1.1 million miles (1.8 million kilometers), or about 4.6 times the distance from Earth ...

Cash crunch for anti-Armageddon asteroid mission

January 25, 2017

A mission to smash a spacecraft into an asteroid moon to alter its trajectory, a possible dry-run for an exercise in saving the Earth from Armageddon, has run into a cash crunch.

Big asteroid swinging by Earth has its own moon

May 30, 2013

Astronomers getting their first close-up glimpse of a giant asteroid about to whiz by Earth found a surprise bonus rock. A smaller moon asteroid is circling the larger space rock, an unusual but not unheard of space phenomenon.

Recommended for you

Discovered: Fast-growing galaxies from early universe

May 24, 2017

A team of astronomers including Carnegie's Eduardo Bañados and led by Roberto Decarli of the Max Planck Institute for Astronomy has discovered a new kind of galaxy which, although extremely old—formed less than a billion ...

2 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

jonesdave
not rated yet Apr 19, 2017
Interesting stuff. What sort of orbits are these asteroids on? Surely they must be very elliptical. Now, let me think; hmmm, wasn't it the idiot Thornhill that said that comets were just asteroids on elliptical orbits? Seems strange that these elliptically orbiting asteroids aren't lighting up like the fourth of July. Wonder why not? Possibly due to the idiot Thornhill being an idiot? Most probably. Anybody care to disagree?
krzychu01230
1 / 5 (1) Apr 24, 2017
Ok, but scenario of Deep Impact was correctly predicted by Thornhill while NASA guys was baffled ; and peanut-shape is more consistent with electrical hypothesis.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.