![]() The key question is whether Bennu’s actual trajectory in 2135 will pass through any of these “keyholes,” which range from several hundred feet to a few miles wide. Bennu has practically no chance of hitting Earth then, but depending on precisely when and where Bennu makes its close approach, our planet’s gravity could tweak the asteroid’s orbit enough to put it on a future collision course.Ĭomputer simulations have identified the small regions of space that Bennu would have to pass through to set up a future impact. Previous predictions had found that Bennu will pass within 75,000 to 330,000 miles of Earth in 2135, possibly taking the asteroid closer to Earth than the moon. A 2014 study found that the asteroid had roughly a 0.037 percent chance of colliding with Earth between 21.īut until now, simulations have run into issues beyond September 2135. These data have let astronomers predict Bennu’s future location reasonably well over the next century.īennu is classified as a “potentially hazardous asteroid,” meaning the object is more than 460 feet (140 meters) wide and could theoretically come within 4.65 million miles of Earth. Pinpointing an asteroidĮver since Bennu’s discovery in September 1999, astronomers have carefully tracked the asteroid’s orbit with ground-based telescopes, including Puerto Rico’s iconic but now lost Arecibo Observatory. An impact would pack the energy of more than 1.1 billion tons of TNT, roughly two million times the energy of last year’s devastating port explosion in Beirut, Lebanon. That asteroid was probably about six miles across Bennu is less than a third of a mile wide, on average.Įven so, a collision with Bennu would be regionally devastating. There’s more than a 99.9 percent chance that Bennu will not hit Earth in the next three centuries, and an impact from Bennu wouldn’t cause a mass extinction like the dino-killing Chicxulub impact 66 million years ago. “This team has made an extremely precise measurement.”ĭespite the slightly higher chance of impact, the risks from Bennu shouldn’t keep anyone awake at night. ![]() ![]() “If you want to be able to predict where is going to go in the future, that prediction is entirely determined by how well you can measure where it is today,” she says. University of Arizona planetary scientist Amy Mainzer, an expert on near-Earth asteroids who wasn’t involved with the study, lauded the team’s “absolutely white-glove” calculations. No other object in the solar system has that level of fidelity to its orbital solution-even Earth!” “We know where it’s going to be over 100 years into the future, within meters. “Bennu is by far the best characterised asteroid in the solar system,” says University of Arizona planetary scientist Dante Lauretta, OSIRIS-REx’s principal investigator and the study’s senior author. That level of precision is like measuring the distance between the Empire State Building and the Eiffel Tower to within a few thousandths of an inch. The team-led by Davide Farnocchia, a navigation engineer at NASA’s Jet Propulsion Laboratory-reached its revised estimate by pinpointing Bennu’s distance from Earth to within about seven feet at dozens of times between 20. On that Tuesday, Bennu has about a 1-in-2,700 chance of hitting Earth. Nearly all of the riskiest encounters with Bennu will occur in the late 2100s and early 2200s, with the single likeliest impact coming on the afternoon of September 24, 2182. The study finds a 1-in-1,750 chance of a future collision over the next three centuries-a slightly higher probability than previously estimated. ![]() The researchers then analysed the impact hazard between now and the year 2300. In a new study published in the scientific journal Icarus, scientists used data from NASA’s OSIRIS-REx spacecraft to make a precise calculation of Bennu’s orbit and its future proximity to our home planet. But hundreds of years from now, there is a small chance that Bennu could slam into Earth. The asteroid, about a third of a mile wide at its equator, poses no immediate threat to our planet. For hundreds of millions of years, a top-shaped rubble pile called Bennu has orbited the sun in relative isolation.
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