OSIRIS-REx predictions

Dec 15, 2019
Congrats to NASA for successfully collecting a sample from asteroid Bennu today. As with every asteroid (and comet) mission to date, the science team will undoubtedly encounter several pieces of evidence that directly contradict the favored model of asteroid and comet origins.

Specifically, I'm predicting that the Bennu sample (if it makes it back to Earth in 2023) will reveal Bennu not to be "primordial" but rather a fragment of a much larger celestial body. It will show evidence of weathering, differentiation, extreme heat signatures, and a far-too-young age (as determined by cosmic ray dating, for example).

Bennu is surely not a loose pile of gravitationally bound "gravel." Rather, it is, like all asteroids and comets, a mostly rocky body. So far all missions to such objects have shown them to be dusty and rocky, and not primordial in any way. They were born in superheated environments, most likely during violent collision or fragmentation events.

Though we won't get sample data back for a few years, even the video taken of the sample collection should reveal clues about the surface's integrity. If Bennu is like Tempel 1, the subject of the Deep Impact mission several years back, all data will show that Bennu's surface is solid rock covered with a layer of regolith. Tempel 1's surface was so hard that the spacecraft's impactor created a violent UV flash, a sure sign of a solid target, not a loose congregation of pebbles or an otherwise porous matrix of material. OSIRIS-REx's data should reveal the same thing about Bennu.