Showing posts with label Frank Drake. Show all posts
Showing posts with label Frank Drake. Show all posts

Sunday 1 April 2018

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?

Thursday 25 February 2010

Are we alone? Wow, Little Green Men and the SETI faithful

According to the film version of Arthur C. Clarke's novel 2010: Odyssey Two, we now live in 'The Year We Make Contact'. Therefore it seems apt to take a quick look at the history of SETI, the Search for Extra-Terrestrial Intelligence, just in case fact should follow fiction. The recently-discovered antics of the Australian octopi that use coconut shells as mobile homes prove that it isn't just the music-loving, film-making and now liquid-quantifying chimpanzees who erode the boundaries between Homo sapiens and other animals. The Gallup mark mirror test has shown that apes, elephants, dolphins and even some birds have a degree of self-awareness exceeding that of human babies less than several months old. When combined with research into animal tool use and the archaeological evidence for rituals conducted by our extinct Neanderthal cousins, our species' mental abilities appear less and less distinctive. So if there are varying degrees of self-aware animals down here, what are the chances of intelligent life "up there"?

New analysis of the Murchison meteorite fragments which landed in Australia in 1969 has found 14,000 carbon-based compounds, including dozens of amino acids different from those known on Earth. If anything, this evidence is more intriguing than the now infamous Martian meteorite ALH 84001 which has so far failed to provide conclusive evidence of fossilised alien nanobacteria. But the idea of life being able to survive outside our comfortable biosphere has gained credence over the past few decades with the discovery of extremophiles, including the diverse organisms that live around submarine volcanic vents and the microbes that can survive gamma radiation several thousand times the dosage lethal to humans.

Whilst there has been a growth of interest in exobiology since the NASA experiments on Mars in the mid-1970s via the two Viking landers, a good deal of today's research investigates the notion of intelligent life elsewhere, largely via radio astronomy. Notable organisations include the Planetary Society, co-founded by the late Carl Sagan, and the Seti Institute, co-founded by Jill Tarter, the real-life model for Sagan's fictional Contact protagonist Eleanor Arroway. Yet despite the lack of positive data after half a century's effort, both the pro and con lobbies maintain passionate support for their ideas. One of the best-known SETI pioneers is American astronomer and astrophysicist Frank Drake, whose eponymous equation has been argued by both sides despite being deemed by some, including author Michael Crichton, as scientifically worthless. This stems from the fact that most of the values in the Drake equation, aiming to establish the potential number of civilisations in the galaxy capable of interstellar communication, are as unknown as when first written in 1960. Over the decades many researchers have had a go at 'filling in the blanks' and achieved results ranging from one (us) to over a million. Clearly, it is not an equation that can be resolved utilising our current knowledge of astrophysics, biology and almost everything in between.

As might be expected the UK's involvement in SETI has been somewhat minimal, although the 76-metre diameter Lovell Radio Telescope at Jodrell Bank has been used intermittently in this context since the late 1990s. Last month even saw the Royal Society host a SETI conference that included such astronomical luminaries as Martin Rees, Jocelyn Bell Burnell and Frank Drake. Unfortunately the traditional British no-nonsense approach lost Jodrell Bank in particular (and the country in general) its chance for pioneering SETI research when Bernard Lovell, in a decision he apparently later regretted, turned down a request to use the very same, then-named Mark 1, radio telescope in 1959.

Although over four hundred planets have been discovered (mostly indirectly) around other stars, none are obviously in the 'Goldilocks zone' where it is believed conditions are suitable for life. Having said that, the recent discoveries of water, mostly as ice, on the Moon, Mars, and two or three other satellites, are obviously positive signs. Then again, there is an enormous difference between those who support the notion of alien microbial life as opposed to intelligent organisms able to transmit signals between solar systems. As early as 1950 physicist Enrico Fermi developed his famous paradox which states that if there are any alien societies capable of interstellar travel, or just communications technology comparable to ours, then we should have found evidence by now. Despite several false alerts such as Jocelyn Bell Burnell's 1967 discovery of pulsars (which she initially labelled as LGM or 'Little Green Men') and the never-repeated 'Wow!' signal detected at Ohio State University in 1977, there has been no unequivocal evidence from the electromagnetic spectrum. In addition, and despite the plethora of orbiting telescopes from Hubble to WISE, there is no evidence for astro-engineering artefacts such as Dyson spheres that a more advanced civilisation might be able to construct.

One international project that has shown the immense level of international grass roots support for the hypothesis is SETI@home, which over the past decade has utilised five million home computers to process radio telescope signal data. Even though such current projects do not involve public money or remove time from research with seemingly more potential of success, there is still plenty of vociferous opposition, even from the scientific community. Arguments range from the practical, such as if we are already moving to fibre optics and digital signals perhaps radio broadcasts are too rare to be detected (some groups have now started laser-based research), to intense speculation on alien motives, which is clearly more in the realm of psychology than science. One of more interesting of the latter is the idea of deliberately non-communicative aliens: since like everyone else SETI researchers have the hard-wired human instinct for exploration, how can we have knowledge of an extraterrestrial psyche until we achieve contact? We surmise at our peril!

Of course another problem facing SETI is the manner in which it has been linked to the lunatic fringe. The unfortunate interest shown in the hypothesis by everyone from New Age mystics to conspiracy theorists taints the idea as verging on pseudoscience, regardless of how scientific the investigations themselves have been. In 1993 NASA's main SETI programme, at one point renamed the High Resolution Microwave Survey in an effort to remove the 'giggle factor', was cancelled after less than one year's operation. But then is it that surprising that US Government support has frequently been withdrawn, leaving only privately funded SETI projects as per today? High-profile supporters including Steven Spielberg and Microsoft co-founder Paul Allen may have boosted its status, but is SETI strictly scientific despite its methods and technology? After all, we could listen for thousands of years without receiving evidence, but as the old adage goes, absence of evidence is not necessarily evidence of absence.

Certainly the zeal with which Carl Sagan, probably the best known SETI advocate from the 1970s to 1990s, approached the enterprise had an almost religious air to it. His novel Contact develops this aspect by making the heroine rely solely on faith rather than physical evidence of her meeting with an extra-terrestrial. It could be argued that by presenting the alien in the guise of the protagonist's father, Sagan replaced conventional religiosity with a paternal God-like being with astounding powers. As Arthur C. Clarke's Third Law states (and as the Aztecs and many others found to their cost): 'Any sufficiently advanced technology is indistinguishable from magic'.

One of Sagan's early claims from the era of Vietnam and Watergate was that receipt of a signal would not only show the possibility of surviving technological adolescence but might also provide information to help us do the same. Since scientific thought is entrenched in the historical and cultural biases of the scientists involved, not to mention the increasing use of models and metaphors at the cutting edge, how easy would it be to understand even scientific concepts from a culture probably millennia more advanced than our own? Even if we could decipher alien scientific data, the next obvious problem is might we inadvertently destroy ourselves via some form of industrial accident, or developments in the $1.2 trillion per annum arms race, brought about by precipitant use of advanced technology? This displays another danger of SETI research: the wide-ranging but pointless speculation in lieu of hard evidence. Until we receive a message, all such conjecture is only of use to acknowledge our own hopes and fears. Even the mildly optimistic notion of extra-terrestrial contact bringing wonder or enchantment to humanity could be countered by slow translation progress in this era of the 140-character Tweet. When the news reports over the ALH 84001 meteorite were at their height in the mid-1990s, I remember work colleague telling me she was heartily sick of hearing about it. Clearly one person's mysterium fascinans (as Stephen Jay Gould might have phrased it), is another's mind-numbing tedium!

How long we will keep listening for is also open to question. If after a few more decades of concerted effort we have still not found definitive evidence, one possibly positive outcome might be the increased promotion of eco-awareness via the obvious rarity of own biologically-active planet. But current estimates suggest we have so far undertaken only about one hundred-trillionth of the radio coverage deemed necessary for a thorough search. It will be at least decades before we can afford to build even robot craft capable of travelling interstellar distances in reasonable spans of time, so until then we have little choice but to rely on our various types of receiver. So why bother at all? For the comparatively small sums involved, there's not much else that could provide such an astonishing potential return. As for the pessimists out there, I can offer nothing better than Monty Python's Eric Idle: "And pray that there's intelligent life somewhere out in space / 'Cause there's bugger all down here on Earth!"

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