Towards the end of the year you may have heard about the recent discovery of the strange asteroid-like object dubbed Ouamuamua. This object is about 400 meters long, but only a few meters wide, so unlike most asteroids, it’s highly elongated. Its very high speed (some estimates seem to be in the range of 200,000 miles per hour, though that seems awfully high to me for a run of the mill asteroid) means that it must have come from outside of the solar system otherwise it would have easily attained escape velocity of the solar system (and its extrapolated path appears to confirm that it has extra-solar origin and is headed back out). Because of its high speed, telescopes were unable to get a close enough look to get precise shape and composition, but we do know it’s unusual! In fact, it’s so unusual that Stephen Hawking among others suggested that it might actually be an alien spaceship (not a conclusion that serious scientists like to arrive at most of the time, but unusual observations sometimes require unusual speculations). Radio telescopic observations detect no signals, thus decreasing the odds that this is an artificial object (we believe most intelligent species would use radio waves for communication and remote control because over wide frequency bands they go unabsorbed by gas and dust in space, unlike other forms of light. They also takes less energy to generate radio waves).
However, I was immediately reminded of 1970’s television series Space: 1999, the premise of which was that the Moon was kicked out of Earth orbit by a massive nuclear explosion and then the whole moon acts like a spaceship wandering about the Galaxy. Though the premise was weak for a number of reasons (any such explosion able to give the Moon that kind of a kick would have enough energy to obliterate the Moon; Even if the Moon were ejected at Ouamuamua type speeds, travel between stars would take thousands of years)some of the individual episodes had interesting alien encounters and considerations of mans’ place in the Universe.
So, it can’t happen with the Moon, but maybe it could happen with a smaller asteroid? So, perhaps we do have aliens after all who had set up a base on this asteroid, and somehow it got ejected into interstellar space (we then again reach the problem of an explosion so immense that even if it didn’t vaporize all of the rocks in the star system, it certainly would have killed any beings camped out on them, or at least any kind of being we could sanely imagine). Or, maybe Ouamuamua really is a space ship of some kind? We may never be able to find out for sure, but it sure has triggered the imagination.
If you are interested in such topics, you may want to look at my book,
The Physics and Astronomy of Science Fiction (Mc Farland Publishing), easily ordered in paper or electronic form through Amazon and other booksellers.