The interstellar asteroid visiting our Solar System may be shielding an icy core
Our Solar System’s recent interstellar visitor — a space rock named `Oumuamua — may be covered in a thick coat of organic material, an outer layer that’s protecting a cache of ice within. This veneer may have acted like a shield, preventing the ice inside `Oumuamua from getting overheated and evaporating when the rock passed close by our Sun. That means this interstellar object may be more like an icy comet and less like an asteroid.
The main distinction between asteroids and comets is their composition: comets are made up of a mixture of ice and rocks, whereas asteroids are mostly rock and metal, without much water. Astronomers think that most of the objects passing in between stars — called interstellar space — are more comet-like than…
