Our Amygdalas are going crazy over the asteroid named Oumuamua (1I/2017 U1) discovered by the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS1) in Hawaii this year. Here’s what’s happening in our brains: it’s not from around here plus it’s a funny shape equals it must be a stricken alien ship spinning out of control. Come on humans, let’s engage our collective pre-frontal cortexes – you know, the thing that enabled us to invent the internet, go to the Moon and eradicate smallpox among other things.
It’s not from around here, which means it doesn’t originate from our Solar System. Well, most of the matter in the universe didn’t originate in our Solar System so that one on its own doesn’t mean Oumuamua is an alien ship. So, what about it’s funny shape? 67P/Churyumov-Gerasimenko was a funny shape too and that wasn’t an alien ship – we know this because that’s where Rosetta went with Philae. Ok, so that’s a sample size of one, of objects that have a funny shape that aren’t alien space ships. Oh, here’s another four that are funny shapes and aren’t alien spacecraft:
It’s not made of asteroid stuff, is another claim, or it would have flung itself apart in its tumbling. Not necessarily, many asteroids are a mix of rock and metal and sometimes the proportion of metal can be quite high, especially nickel and iron. The size of the object is estimated to be about 400m long meaning it could well hold itself together if the density of the material was not too low and quite cohesive. Plus it’s rotational period was estimated to be 7.34 +/- 0.06 hours (Nature Article). That’s not very fast. The same article describes the colour of the object to be consistent with objects found in our own outer Solar System. Analysis of its velocity and the hyperbolic shape of its trajectory suggest it’s not from around here.
It has an apparent red colour which is consistent with organic rich surfaces found on comets but it doesn’t have a tail as would be expected by something passing within 38 million kms of the sun. This would indicate it does not have any ice near its surface or that would have evaporated off and made a distinctive tail. The object was discovered by Pan-STARRS1 which is a 1.8m telescope in Hawaii. As more and more sky surveys are undertaken and equipment and processing improves we are likely to find more and unusual objects. So Oumuamua could just be the first of the class of objects that we will see more of overtime simply because we haven’t been able to seem them before.