Falling chunks of massive asteroid pose a future threat to Earth

A binary asteroid has been leaking dust into our atmosphere, but if it totally cracks up we could have problems.

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Eric Mack
2 min read

An asteroid that could break apart has a 6 percent chance of raining down on Earth in the next 10 million years.


Astronomers have traced a 2017 fireball over Japan to a massive nearby asteroid that could eventually break up and shower Earth with dangerous meteors. 

It was around 1 a.m. local time on April 29, 2017 when an exceptionally bright and slow fireball lit up the skies over Kyoto, Japan. Later, a team of researchers from the National Astronomical Observatory of Japan (NAOJ), Kyoto Sangyo University (KSU) and the Nippon Meteor Society found the dust particle that flamed out in grand style that evening had an orbit similar to the double (or binary) asteroid 2003 YT1

"We uncovered the fireball's true identity," Toshihiro Kasuga, a visiting scientist at NAOJ and KSU, said in a release Wednesday. "The 2017 fireball and its parent asteroid gave us a behind-the-scenes look at meteors."

The team's research was published Monday in The Astronomical Journal


Images capturing the 2017 fireball from different angles and a map showing where the cameras were located. 

NAOJ/Kasuga et al.

The team believes that at some point in the past, 2003 YT1 cracked under pressure from something called the YORP effect that essentially caused it to twist in an odd way as it rotated. That break in the asteroid, even a small one, can release dust that makes its way to our atmosphere and burns up as fireballs. 

Most dust particles will burn up harmlessly in our atmosphere, but if 2003 YT1 completely breaks apart into smaller asteroids, it could eventually pose a threat. The double asteroid is a bit of a monster, with the bigger rock measuring about 1.2 miles (2 km) and orbited by a 690-foot (210 m) companion.

"The potential breakup of the rock could be dangerous to life on Earth," Kasuga says. "Those resulting asteroids could hit the Earth in the next 10 million years or so."

So probably nothing to worry about anytime soon, but 2003 YT1 is a reminder that the situation in space is always changing and it's worth keeping a close eye (or thousands of eyes) on the sky. 

Watch this: How NASA's DART could save the planet from a killer asteroid

Originally published Jan. 15.