by Marcia Dunn | The Associated Press
Cape Canaveral, Fla. The good news is that scientists have better control over the whereabouts of asteroid Bennu for the next 200 years. The bad news is that the space rock has a slightly higher chance of orbiting Earth than previously thought.
But don’t worry: Scientists said Wednesday that the chances are still slim that Bennu will strike us in the next century.
“We shouldn’t be too concerned about it,” said David Farnochia, a scientist at NASA’s Center for Near Earth Object Studies at the Jet Propulsion Laboratory in Pasadena, California, who served as the study’s lead author.
According to Farnochia, while the likelihood of a strike has increased from 1-in-2,700 to 1-in-1,750 over the next century or two, scientists now have a better idea of Bennu’s route for NASA’s Osiris-Rex spacecraft. .
“So I think overall, the situation has improved,” he told reporters.
The spacecraft makes a long, round trip back to Earth after collecting samples from the large, swirling debris plume of an asteroid believed to be one of the two most dangerous known asteroids in our solar system. Samples are due here in 2023.
Before Osiris-Rex reached Bennu in 2018, telescopes provided solid insight into the asteroid, which measures about one-third of a mile (half a kilometer) in diameter. The spacecraft collected enough data over 2 1/2 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 another dangerous space rock comes our way.
Before Osiris-Rex arrived at the scene, scientists put the probability of Bennu hitting Earth at 1-in-2,700 during the year 2200. It is now 1-in-1,750 through the years 2300. The most dangerous day is September 24, 2182.
Bennu will make a close encounter with Earth in 2135 when it will pass within half the distance of the Moon. Earth’s gravity could change its future path and put it on a collision course with Earth in the 2200s – a less likely thing now based on Osiris-Rex observations.
If Bennu did hit Earth, it would not wipe out life dinosaur-style, but would create a crater about 10 to 20 times the size of an asteroid, said NASA planetary defense officer Lindley Johnson. The area of devastation would be enormous: as much as 100 times the size of the crater.
If an object hits the eastern coastline the size of Bennu, it will “destroy a lot of things up and down the coast,” he told reporters.
Scientists are already ahead of the curve with Bennu, which was discovered in 1999. Johnson said finding threatening asteroids earlier increases the chances and options out of our way.
“A hundred years from now, who knows what the technology is going to be like?” he said.
In November, NASA plans to launch a mission to strike and close an asteroid. The experimental target would be the moonlighting of a large space rock.