Engagement with Oumuamua: is our first interstellar visitor an alien spacecraft?

It's often said that fact follows fiction but there are times when some such instances appear to be uncanny beyond belief.  One relatively well-known example comes from the American writer Morgan Robertson, whose 1898 novella The Wreck of the Titan (originally entitled Futility) eerily prefigured the 1912 loss of the Titanic. The resemblances between the fictional precursor and the infamous passenger liner are remarkable, including the month of the sinking, the impact location, and similarities of size, speed and passenger capacity. I was first introduced to this series of quirky coincidences via Arthur C. Clarke's 1990 novel The Ghost from the Grand Banks, which not incidentally is about attempts to raise the Titanic. The reason for including the latter reference is that there may have just been an occurrence that involves another of Clarke's own works.

Clarke's 1973 award-winning novel Rendezvous with Rama tells of a 22nd century expedition to a giant interstellar object that is approaching the inner solar system. The fifty-four kilometre long cylinder, dubbed Rama, is discovered by an Earthbound asteroid detection system called Project Spaceguard, a name which since the 1990s has been adopted by real life surveys aiming to provide early warning for Earth-crossing asteroids. Rama is revealed to be a dormant alien spacecraft, whose trajectory confirms its origin outside of our solar system. After a journey of hundreds of thousands of years, Rama appears to be on a collision course with the Sun, only for it to scoop up solar material as a fuel source before heading back into interstellar space (sorry for the spoiler, but if you haven't yet read it, why not?)

In October last year astronomer Robert Weryk at the Haleakala Observatory in Hawaii found an unusual object forty days after its closest encounter with the Sun. Initially catalogued as 1I/2017 U1, the object was at first thought to be a comet, but after no sign of a tail or coma it was reclassified as an asteroid. After another week's examination 1I/2017 U1 was put into a class all by itself and this is when observers began to get excited, as its trajectory appeared to proclaim an interstellar origin.

As it was not spotted until about thirty-three million kilometres from the Earth, the object was far too small to be photographed in any detail; all that appears to telescope-mounted digital cameras is a single pixel. Therefore its shape was inferred from the light curve, which implied a longest-to-shortest axis ratio of 5:1 or even larger, with the longest dimension being between two hundred and four hundred metres. As this data became public, requests were made for a more familiar name than just 1I/2017; perhaps unsurprisingly, Rama became a leading contender. However, the Hawaiian observatory's Pan-STARRS team finally opted for the common name Oumuamua, which in the local language means 'scout'.

Various hypotheses have been raised as to exactly what type of object Oumuamua is, from a planetary fragment to a Kuiper belt object similar - although far smaller than - Pluto.  However, the lack of off-gassing even at perihelion (closest approach to the Sun) implies that any icy material must lie below a thick crust and the light curve suggests a denser material such as metal-rich rock. This sounds most unlike any known Kuiper belt object.

These unusual properties attracted the attention of senior figures in the search for extra-terrestrial intelligence. Project Breakthrough Listen, whose leadership includes SETI luminaries Frank Drake, Ann Druyan and Astronomer Royal Martin Rees, directed the world's largest manoeuvrable radio telescope towards Oumuamua. It failed to find any radio emissions, although the lack of a signal is tempered with the knowledge that SETI astronomers are now considering lasers as a potentially superior form of interstellar communication to radio.

The more that Oumuamua has been studied, the more surprising it appears. Travelling at over eighty kilometres per second relative to the Sun, its path shows that it has not originated from any of the twenty neighbouring solar systems. Yet it homed in on our star, getting seventeen percent nearer to the Sun than Mercury does at its closest. This seems to be almost impossible to have occurred simply by chance - space is just too vast for an interstellar object to have achieved such proximity. So how likely is it that Oumuamua is a real-life Rama? Let's consider the facts:

1. Trajectory. The area of a solar system with potentially habitable planets is nicknamed the 'Goldilocks zone', which for our system includes the Earth. It's such a small percentage of the system, extremely close to the parent star, that for a fast-moving interstellar object to approach at random seems almost impossible. Instead, Oumuamua's trajectory was perfectly placed to obtain a gravity assist from the Sun, allowing it to both gain speed and change course, with it now heading in the direction of the constellation Pegasus.
2. Motion. Dr Jason Wright, an associate professor of astronomy and astrophysics at Penn State University, likened the apparent tumbling motion to that of a derelict spacecraft, only to retract his ideas when criticised for sensationalism.
3. Shape. All known asteroids and Kuiper belt objects are much less elongated than Oumuamua, even though most are far too small to settle into spherical shape due to gravitational attraction (the minimum diameter being around six hundred kilometres for predominantly rocky objects). The exact appearance is unknown, with the ubiquitous crater-covered asteroid artwork being merely an artist's impression. Astronautical experts have agreed that Oumuamua's shape is eminently suitable for minimising damage from particles.
4. Composition. One definitive piece of data is that Oumuamua doesn't emit clouds of gas or dust that are usually associated with objects of a similar size. In addition, according to a report by the American Astronomical Society, it has an 'implausibly high density'. Somehow, it has survived a relatively close encounter with the Sun while remaining in one piece - at a maximum velocity of almost eighty-eight kilometres per second relative to our star!
5. Colour. There appears to be a red region on the surface, rather than a uniform colour expected for an object that has been bombarded with radiation on all sides whilst in deep space for an extremely long period.

So where does this leave us? There is an enormous amount of nonsense written about alien encounters, conspiracy theories and the like, with various governments and the military seeking to hide their strategies in deliberate misinformation. For example, last year the hacker collective Anonymous stated that NASA would soon be releasing confirmation of contact with extraterrestrials; to date, in case you were wondering, there's been no such announcement. Besides which, wouldn't it more likely to come from a SETI research organisation such as the Planetary Society or Project Breakthrough Listen?

Is there any evidence to imply cover-up regarding Oumuamua? Here's some suggestions:

1. The name Rama - already familiar to many from Arthur C. Clarke's novel and therefore evocative of an artificial object - was abandoned for a far less expressive and more obscure common name. Was this an attempt to distance Oumuamua from anything out of the ordinary?
2. Dr Wright's proposals were luridly overstated in the tabloid media, forcing him to abandon further investigation. Was this a deliberate attempt by the authorities to make light of his ideas, so as to prevent too much analysis while the object was still observable?
3. Limited attempts at listening for radio signals have been made, even though laser signalling is now thought to be a far superior method. So why have these efforts been so half-hearted for such a unique object?
4. The only images available in the media are a few very samey artist's impressions of an elongated asteroid, some pock-marked with craters, others, especially animations, with striations (the latter reminding me more of fossilised wood). Not only are these pure speculation but none feature the red area reported from the light curve data. It's almost as if the intention was to show a totally standard asteroid, albeit of unusual proportions. But this appearance is complete guesswork: Oumuamua has been shoe-horned into a conventional natural object, despite its idiosyncrasies.

Thanks to Hollywood, most people's ideas of aliens are as implacable invaders. If - and when - the public receive confirmation of intelligent alien life will there be widespread panic and disorder? After all, the Orson Welles' 1938 radio version of H.G. Wells' War of the Worlds led some listeners to flee their homes, believing a Martian invasion had begun. Would people today be any different? The current following of dangerous fads such as paleo diets and raw water, never mind the paranoid conspiracy theories that fill the World Wide Web, lead me to expect little change from our credulous forbears.

The issue of course, comes down to one of security. Again, science fiction movies tend to overshadow real life space exploration, but the fact is that we have no spacecraft capable of matching orbits with the likes of Oumuamua. In Arthur C. Clarke's Rendezvous with Rama, colonists on 22nd century Mercury become paranoid with the giant spacecraft's approach and attempt to destroy it with a nuclear missile (oops, another spoiler there). There is no 21st century technology that could match this feat, so if Oumuamua did turn out to be an alien craft, we would have to hope for the best. Therefore if, for example, the U.S. Government gained some data that even implied the possibility of artifice about Oumuamua, wouldn't it be in their best interest to keep it quiet, at least until it is long gone?

In which case, promoting disinformation and encouraging wild speculation in the media would be the perfect way to disguise the truth. Far from being an advanced - if dead or dormant - starship, our leaders would rather we believed it to be a simple rocky asteroid, despite the evidence to the contrary. Less one entry for the Captain's log, and more a case of 'to boulderly go' - geddit?