Slim Chance Asteroid Bennu Will Collide With Earth in 2300

The spacecraft OSIRIS-REx spent two years close to asteroid Bennu before leaving earlier this year, and now researchers have predicted there is a very small chance the asteroid, which is 500 meters wide, could collide with Earth in the future.

NASA researchers have used data from this expedition to find out more about the asteroid’s orbit, which has allowed them to predict its future positions. Though the asteroid will make a close approach to Earth in 2135, it won’t yet pose any danger to us. However, in the far future of the year 2300, there is a 1 in 1,1750 chance that the asteroid will strike the planet.

“The OSIRIS-REx data give us so much more precise information, we can test the limits of our models and calculate the future trajectory of Bennu to a very high degree of certainty through 2135,” said study lead Davide Farnocchia of the Center for Near-Earth Object Studies (CNEOS). “We’ve never modeled an asteroid’s trajectory to this precision before.”

Although there’s no reason to start planning your off-world activities for 300 years in the future, this is a demonstration of how asteroid tracking technology is improving. And that’s important for spotting other potentially dangerous asteroids and tracking them as they move through our solar system — so we’d have warning if the Earth ever was threatened by an impact.

“NASA’s Planetary Defense mission is to find and monitor asteroids and comets that can come near Earth and may pose a hazard to our planet,” explained Kelly Fast, program manager for the Near-Earth Object Observations Program at NASA Headquarters in Washington. “We carry out this endeavor through continuing astronomical surveys that collect data to discover previously unknown objects and refine our orbital models for them. The OSIRIS-REx mission has provided an extraordinary opportunity to refine and test these models, helping us better predict where Bennu will be when it makes its close approach to Earth more than a century from now.”

By using the data from OSIRIS-REx, such as information about the asteroid’s size, mass, and composition as well as about its trajectory, the researchers were able to come up with these more precise predictions of its future orbit. Plus, the spacecraft swiped a sample of the asteroid that it is bringing back to Earth now, which will give even more information.

“The orbital data from this mission helped us better appreciate Bennu’s impact chances over the next couple of centuries and our overall understanding of potentially hazardous asteroids — an incredible result,” said Dante Lauretta, OSIRIS-REx principal investigator and professor at the University of Arizona. “The spacecraft is now returning home, carrying a precious sample from this fascinating ancient object that will help us better understand not only the history of the solar system but also the role of sunlight in altering Bennu’s orbit since we will measure the asteroid’s thermal properties at unprecedented scales in laboratories on Earth.”

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