- NASA’s OSIRIS-REx asteroid probe has spotted the asteroid Bennu flinging pieces of its own surface into space.
- These “particle ejection events” happen all the time, and NASA scientists have already spotted over 300 instances of it.
- Going forward, scientists hope to find an explanation for why it is happening, and what processes on or beneath the surface are driving it.
NASA’s asteroid probe OSIRIS-REx has been flying around the massive space rock known as Bennu for almost two years now. During that time, it’s made a number of interesting observations of the asteroid. For starters, the surface is incredibly messy, which was an unexpected discovery for scientists.
Now, NASA has revealed that the asteroid’s surface is actually shedding. The rock is regularly releasing material from its surface, and scientists have been observing and tracking this material for some time. The particles come in bursts, and scientists have been eager to understand what is behind the seemingly random ejections.
The particles that Bennu is shedding were discovered almost completely on accident. During some routine observations, the researchers noted that there were things in the space around Bennu that weren’t supposed to be there.
“I was looking at the star patterns in these images and thought, ‘huh, I don’t remember that star cluster,'” Carl Hergenrother, lead author of some new research papers on the phenomenon, said in a statement. “I only noticed it because there were 200 dots of light where there should be about 10 stars. Other than that, it looked to be just a dense part of the sky.”
After taking a closer look, the scientists quickly realized that the mysterious “stars” they were seeing were actually tiny bits of the asteroid itself. The question then was why were these particles floating in space, and how did they escape the surface of Bennu?
“We thought that Bennu’s boulder-covered surface was the wild card discovery at the asteroid, but these particle events definitely surprised us,” Dante Lauretta, OSIRIS-REx principal investigator, says. “We’ve spent the last year investigating Bennu’s active surface, and it’s provided us with a remarkable opportunity to expand our knowledge of how active asteroids behave.”
According to NASA, the OSIRIS-REx team has already observed a whopping 300 “particle ejection events” coming from the surface of the asteroid. That’s a pretty wild figure and one that is only making the phenomenon more mysterious. The particles are very tiny, making them difficult to track, but the scientists have been doing their best to figure out what is going on while containing their own excitement for the new discovery.
“One particle came down, hit a boulder and went back into orbit,” Hergenrother notes. “If Bennu has this kind of activity, then there is a good chance all asteroids do, and that is really exciting.”