Have important plans for September 24, 2182? Consider rescheduling. That’s the date when a half-mile-wide asteroid could pass close—very close—to Earth.
While the odds are slim, there is a chance that Bennu—currently about 190 million miles away, according to the The Sky Live website—could collide with our planet. Scientists give it a one-in-1,175 (0.0037%) chance, reports Daniel Clery for Science magazine.
“I don’t think we need to do anything about Bennu,” planetary scientist Lindley Johnson of NASA’s Planetary Defense Coordination Office says in a press briefing, according to Science.
Unless physics plays a hand, that is. The asteroid’s trajectory could be affected by numerous factors, including another nearby flyby in 2135, reports Nell Greenfieldboyce for NPR. Gravitational and other forces by the sun, Earth and moon could cause an alteration in the flightpath that might steer this “rubble pile” of a flying object—also known as asteroid 101955 Bennu—onto a direct path with us.
“So there is no particular reason for concern,” Davide Farnocchia at the Center for Near Earth Object Studies, part of NASA’s Jet Propulsion Laboratory, tells NPR. “We have time to keep tracking the asteroid and eventually come to a final answer.”
These latest projections are the result of a new data provided by NASA’s OSIRIS-REx spacecraft, which actually landed on Bennu in 2018. Scientists used that information to calculate the threat to Earth from this and other objects soaring through space.
As it zooms by the Earth in 2135, Bennu's fate will be determined by what is known as a gravitational keyhole that could alter the asteroid's trajectory and send it on a course aimed directly at us. It could also be impacted by what is known as the Yarkovsky effect, when the asteroid accelerates after absorbing heat from the sun.
If either scenario plays out, it could really rock our world—literally.
“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,” Johnson tells Kenneth Chang of the New York Times. “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.”
Scientists are not worried, though. Given the slim chance of a trajectory change, along with the fact that a possible collision is still 161 years away, there should be an opportunity to do something to alter its course if need be.
“So there is no particular reason for concern,” Farnocchia tells NPR. “We have time to keep tracking the asteroid and eventually come to a final answer.”