Our first interstellar visitor 'Oumuamua may be an ice chunk blasted off an alien Pluto

In 2017, a mysterious interstellar visitor passed through our inner solar system.

Dubbed 1I/'Oumuamua, it defied explanation. Its orbit made it clear it came from interstellar space, but what was it? At first we thought it was an asteroid. When it passed the Sun and began moving back out into the depths of space, it was seen to be slowing, as you might expect as the Sun's gravity pulled it back… but it wasn't slowing enough. This made it seem more like a comet; if it were made of ice this would...