The newest: It may be a hydrogen iceberg slowly grown in the core of a gigantic star-making factory and nudged into a galactic orbit.

We know this from its orbit: Due to the Sun's gravity, objects orbiting it move at speeds that depends on the shape of their orbit and distance from the Sun.

What they came up with was molecular hydrogen: Two hydrogen atoms bound together to make H2.

It might be pancake shaped or elongated like a cigar.

Previous studies have found it more likely that 'Oumuamua is shaped like a pancake, a flattened spheroid something like 115x111x19 meters in size.

This part is neat: If it's a hydrogen iceberg, that shape arises naturally.

Hydrogen ice sublimates at a very low temperature, so this rapidly started sculpting the shape of 'Oumuamua, flattening it into a pancake.

The authors speculate it formed in the middle of a huge, dense, and extremely chilly giant molecular cloud.

They expect a lot of objects like this can be made, most of which are destroyed when stars form, but some of which drift out of the clouds and into space.

'Oumuamua being made of lots of hydrogen ice does seem to explain a lot of its characteristics, even the really weird stuff?

It wasn't seen because we didn't see 'Oumuamua until it was too far away, and no UV observations were made.

Perhaps the European Space Agency's Comet Interceptor, designed to catch up to fast-moving objects like 'Oumuamua, will be able to help.

If this idea is right, then molecular clouds make lots of them, so maybe we won't have to wait too long.