• New formation theory explains the mysterious interstellar object ‘Oumuamua’ (UC Santa Cruz)

The proliferation of survey telescopes is helping us quantify just what fills our sky and flies through our solar system. Recently, we’ve started turning up extrasolar asteroids and comets as they stumble into our system. Asteroid Oumuamua is one of those objects, and it’s unusual shape brought no end of confusion and speculation to its discovery.  Shaped like a needle or cigar, Oumuamua made people think of the spacecraft from Rendezvous with Rama. We just haven’t seen anything this long and skinny before, and spacecraft seemed like as valid an idea as any other, and while the least probable explanation, it is at least understandable. Physical models… well they were harder to come up with.

But one team did manage to find a way. In a new paper with led author Yun Zhang, it’s postulated that as Oumuamua passed near its parent star, it was partiatially tidally disrupted, and the resulting crumbles were stretched out into a broken elongated cloud, until it gravitationally re-solidified into the object we see today.

We know that comets break up – we’ve seen both Comet Atlas and Borisov shatter in the past couple weeks – and it is reasonable to believe that asteroids can and have undergone this same process. 

This paints us a picture or Oumuamua being a tortured asteroid that was stretched beyond breaking, but held in a new form. This process was likely part of what sent the object on an escape trajectory, and it is because of the asteroid-breaking event that Oumuamua was able to visit us.