This undated image made available by NASA shows the asteroid Bennu. Scientists said Wednesday they have a better handle on the whereabouts of asteroid Bennu over the next 200 years. (NASA/Goddard/University of Arizona/CSA/York/MDA via AP)
Cape Canaveral, Florida – The good news is that scientists are better able to get a handle on the whereabouts of the asteroid Bennu over the next 200 years. The bad news is that space rocks have a slightly higher chance of hitting Earth than previously thought.
But don’t worry: Scientists reported Wednesday that the odds are still very low that Bennu will crash into us in the next century.
“We shouldn’t worry too much about that,” said David Farnocchia, a scientist at NASA’s Center for Near-Earth Object Studies at the Jet Propulsion Laboratory in Pasadena, Calif., who served as lead author of the study.
While the odds of a strike have risen from 1 in 2700 to 1 in 1750 over the next century or two, scientists now have a much better idea of Bennu’s trajectory thanks to NASA’s Osiris-Rex spacecraft, according to Farnokia.
“So I think the situation has generally improved,” he told reporters.
The spacecraft heads to Earth in a long circular loop after collecting samples from an asteroid’s large rotating rubble pile, considered one of the most dangerous known asteroids in our solar system. Samples are due here in 2023.
Before Osiris-Rex reached Bennu in 2018, telescopes provided insights into the asteroid, which is about a third of a mile in diameter. The spacecraft collected enough data over the course of two and a half years to help scientists better predict the asteroid’s orbital path in the future.
Their findings – published in the journal Icarus – should also help chart the course of other asteroids and give Earth a better fighting chance if and when another dangerous space rock heads our way.
Before the Osiris-Rex reached the scene, scientists estimated the odds of Bennu hitting Earth during the year 2200 at 1 in 2700. Now it’s 1 in 1750 until the year 2300. The single most threatening day is September 24, 2182.
Bennu will encounter Earth closely in the year 2135 when it passes at a distance of half the distance from the Moon. Earth’s gravity could modify its future course and put it on a collision course with Earth in the 22nd century – a less likely possibility now based on observations of OSIRIS REx.
Lindley Johnson, NASA’s planetary defense officer, said that if Bennu collides with Earth, it will not wipe out life, similar to a dinosaur, but rather create a crater roughly 10 to 20 times the size of an asteroid. The area of destruction will be much larger: up to 100 times the size of the crater.
“It would pretty much destroy things up and down the coast,” he told reporters.
Scientists are already ahead of the curve with Bennu, who was discovered in 1999. Finding previously threatened asteroids increases the chances and options for pushing them out of our way, Johnson said.
“A hundred years from now, who knows what the technology will be?” He said.
In November, NASA plans to launch a mission to derail an asteroid by colliding with it. The experimental target would be a larger space rock moon.