New images from asteroid probe yield clues on planet formation

WASHINGTON: Photographs snapped by a shoebox-sized probe that explored the near-Earth asteroid Ryugu offer new clues about its composition, insights that are expected to help scientists understand the formation of our solar system.

The German-French Mobile Asteroid Surface Scout (MASCOT) was dropped off by Japan’s Hayabusa2 spacecraft on October 3, 2018, free-falling from a height of 41 meters (135 feet) for six minutes before it hit the surface.

It then bounced a couple of times — reaching a height of 17 meters on the first bounce — before coming to rest. Ryugu is just 900 meters wide and so its gravity is 66,500 times weaker than Earth’s. Had MASCOT been equipped with wheels, its forward motion would have launched it back into space.

Instead, it hopped around the surface using the tiny amount of momentum generated by a metal swing arm attached to its boxy body, which weighed 10 kilograms (22 pounds). In addition to taking temperature readings and other measurements, MASCOT sent back a series of pictures showing the asteroid is covered with two types of rocks and boulders: dark and rough ones with crumbly surfaces resembling cauliflowers, and bright and smooth ones. “The interesting thing there is, it really shows that Ryugu is the product of some kind of violent process,” Ralf Jaumann of the German Aerospace Center told AFP.

He is the lead author of a paper describing the findings, published Thursday in the journal Science. Ryugu may be the “child” of two parent bodies that collided, broke up and were then pulled back together by gravity, the researchers say. Alternatively, it could have been struck by another body that created different interior temperature and pressure conditions, creating the two types of material.

Many of the rocks contain small blue and red “inclusions” — material trapped in the rock during its formation — much like a type of rare, primordial meteorites found on Earth called carbonaceous chondrites. “This material is primitive material — it’s the very first material of the solar nebula,” or the cloud of interstellar dust and gas that formed the planets of our system, said Jaumann.