Scientists think they know why interstellar object 'Oumuamua moved so strangely

https://www.npr.org/2023/03/22/ [login to see] /scientists-think-they-know-why-interstellar-object-oumuamua-moved-so-strangely
Scientists have come up with a simple explanation for the strange movements of our solar system's first known visitor from another star.

In October of 2017, astronomers in Hawaii spotted an object they called 'Oumuamua, which means "a messenger from afar arriving first," according to NASA. The reddish object was shaped like a cigar or a pancake, and was over 300 feet long. Its trajectory indicated that it had come from another solar system, traveling through the Milky Way galaxy for hundreds of millions of years before encountering our sun.

Oddly, this interstellar object appeared to be slightly accelerating in a way that normally is associated with the outgassing of some kind of material. But astronomers couldn't detect any comet-like tail of dust or gas.

Over the last few years, some speculated that the object must be made of exotic materials, and the mystery even led to suggestions that 'Oumuamua could be some kind of alien probe or spaceship.

Now, though, in the journal Nature, two researchers say the answer might be the release of hydrogen from trapped reserves inside water-rich ice.