Oumuamua Revisited, Still No Aliens

A few days ago Milky-Way.kiwi reported on the interstellar object named Oumuamua. This was an object travelling very fast, in a hyperbolic trajectory, meaning we probably won’t see it again and that it was almost certainly from outside of our Solar System. It’s now well on its way back out of our Solar System but not before winding a few people up into thinking it might be an alien ship that has broken down. This “theory” mainly came about because of the unusual shape of the asteroid. When conducting observations of the object it was found to have an odd light pattern that would indicate something rather long was rotating – or tumbling. Various calculations were performed and the rough estimate was that the object was probably about 400m long, some folks thought that this must certainly mean it’s an alien spacecraft with broken down engines. Here’s the trajectory of the asteroid from Wikipedia:

Because of all the excitement the Breakthrough Listen Initiative combed data from turboSETI to see if anything had been transmitted from Oumuamua, as of yet nothing has been found. They did some serious number crunching, going through about 90TB of data. They used an instrument on the back of the Robert C. Byrd Green Bank Telescope in West Virginia and scanned frequencies between 1Ghz and 12Ghz and haven’t found anything yet – though there is still some processing to go. The below image is from the William Herschel Telescope and was credited to Alan Fitzsimmons from Queen’s University in Belfast and published on http://www.phys.org.

Not quite the stylised artists impression picked up by popular media, but that image is the real deal, though too small to see the phaser canons. The team of scientists from Queen’s University (you can read all about it here) determined that Oumuamua could in fact have an icy core of comet like material and be protected from evaporation by a thick layer of organic material created through exposure to the interstellar medium. They observed a similar colour of the surface to icy bodies in the outer reaches of our Solar System and have suggested that this might mean that similar processes found in the formation of objects in our own Solar System might be similar elsewhere. Given this is the first interstellar object observed, we might have to wait until a few more are seen before we draw too many conclusions, though I think we can safely assume we don’t have to mount a rescue mission to a broken alien space ship.

Another question that scientists are still grappling with is, where did it come from. There is some suggestion that it’s remarkably high speed of more than 25 kms is about the same as most stuff hurtling around in this part of our galaxy. Matija Ćuk suggests that the origin might be from a planet that was pulled apart by tidal forces and then ejected because of a dense star in a binary system, they suggest that a red dwarf could tidally disrupt a planet enough to rip of fragments.

So we still don’t know where it came from other than it might be from somewhere near by but we have a fair idea of what it might be made of and it’s shape and it has given us a unique chance to look at something not from our Solar System. With the continued development of better telescopes and surveys we are likely to see more of these interstellar visitors in the future which will give us more opportunities to understand these sorts of objects and hopefully answer the unanswered questions from Oumuamua’s brief visit.