Photo: Pixabay One of my favourite science fiction novels is Rendezvous with Rama, written by Arthur C. Clarke in 1973. In the story, our telescopes detect an object moving into the inner Solar System at a speed too high for it to be orbiting the Sun.
It is a visitor from interstellar space. In addition, it is not something roughly spherical, it is a huge, rotating cylinder. With great difficulty a spacecraft rendezvous with it, and discovers it is an interstellar spacecraft.
It is rotating to provide artificial gravity for those inside. Fears of an imminent alien invasion are dispelled when the space ship flies by the Sun and heads back out into the gulfs between the stars, on a journey taking thousands, or tens of thousands, of years. On Oct.
19, 2017, the Pan-STARRS telescope in Hawaii picked up a faint object moving inward into the Solar System. It was moving far too quickly to be orbiting the Sun, which meant it was coming in from interstellar space. However, unlike the object in the story, this one was not an alien spacecraft.
At first, scientists thought it was a comet, a lump of dirty ice, similar to the comets that are members of our Solar System. Out on the edges of the Solar System, where it is very cold, there are lots of lumps of rock and dirty ice left over from the birth of the Sun and planets. These lumps contain bubbles of gas and various volatile organic chemicals.
However, out there it is very cold, so all these ingredients can remain undisturbed for billio.