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Scientists have been tracking a giant asteroid that is the size of the Empire State Building as it hurdles through space towards Earth. After reviewing new data gathered by NASA's Osiris-Rex spacecraft, they have increased the odds that the asteroid, named Bennu, will strike the Earth in the next three hundred years.
The scientists said we have nothing to worry about. The chance of impact is still slim, with a 1-in-1,750 chance, compared to the previous estimate of a 1 in 2,700 chance the asteroid will hit the Earth.
"It's not a significant change," said Davide Farnocchia, a scientist at the NASA Jet Propulsion Laboratory in California. "I'm not any more concerned about Bennu than I was before. The impact probability remains really small."
The asteroid is still forecast to come within 125,000 miles of the planet, which is about half the distance between the Earth and the moon. There is a slight chance that as the asteroid approaches Earth, it will get caught in a "gravitational keyhole" that could send it on a collision course about 50 years later.
While Bennu is not large enough to be considered a planet killer, it could cause a massive swath of devastation if it collided with the Earth.
"You can usually, by rule of thumb, say the crater size is going to be 10 to 20 times the size of the object," said Lindley Johnson, the planetary defense officer at NASA. "So a half-kilometer-sized object is going to create a crater that's at least five kilometers in diameter, and it can be as much as 10 kilometers in diameter. But the area of devastation is going to be much, much broader than that, as much as 100 times the size of the crater. So an object Bennu's size impacting on the Eastern Seaboard states would pretty much devastate things up and down the coast."
Osiris-Rex is now returning to Earth after collecting samples from the massive asteroid. It is expected to arrive in 2023, and scientists hope to learn more about the giant space rock after examining the mineral samples.