‘The nerd side of me is just ecstatic!’ You bet it is. This is a guy who has just discovered a four-planet solar system 600 light years from Earth. His name is Andrew Grey, and he’s not an astronomer. At the time of this discovery he was a 26-year-old car mechanic from Darwin in far-northern Australia with a lifelong interest in astronomy, whose persistence in trawling through a thousand or so light curves – star brightness graphs – had been rewarded big-time. And on live TV, to boot.
It was on Stargazing Live – a three-night TV blockbuster on Australia’s national broadcaster, the ABC. The show sparked a frenzy of citizen science, and the challenge was to find the tell-tale signatures of planets orbiting distant stars in a mass of data from space. Known as exoplanets, these objects have been discovered in profusion over the past two decades, with more than 4000 known today. Very few have been seen directly, however, and most have revealed themselves by the subtle effects they have on their parent stars’ light. The Stargazing Live data, for example, were newly downloaded from NASA’s Kepler spacecraft, whose primary mission was to stare at 100 000 stars. Not just staring for the sake of it, but staring in the hope of recording minuscule dips in brightness that would reveal the passage of a planet across a star’s disc. This so-called ‘transit method’ is today’s gold standard for finding exoplanets, having netted most of those currently known. And Andrew found a star with not just one, but four transiting planets.
What is truly staggering about his find is how it compares with the discovery of the first exoplanet in 1995. Everything is different. The technology, the internet access, the level of popular interest – even the social environment that allows an enthusiastic amateur stargazer to participate in front-line scientific research, and ‘to be published alongside people that went to university for years and years and for me, just a mechanic from Darwin, to have my name on it – I think it’s pretty amazing’. So do I, Andrew, and hats off to you. (And, for the record, to the several dozen other Australians who were pipped at the post in discovering the same four-planet system during the show.)
STARGAZING LIVE MADE A BIG THING OF CITIZEN SCIENCE. But what is citizen science, and how does it work? The dictionary definition is ‘the collection and analysis of data relating to the natural world by members of the general public, typically as part of a collaborative project with professional scientists’. But citizen science means different things to different people, depending on what is being expected of the citizen. And there are similar terms, such as ‘crowd sourcing’. Are they the same thing?
Well-known Swiss astrophysicist and citizen science proponent, Kevin Schawinski, is pretty definite about that. Referring to his best-known project, Galaxy Zoo, he says, ‘we prefer to call this citizen science because it’s a better description of what you’re doing. You’re a regular citizen but you’re doing science. Crowd sourcing sounds a bit like you’re just a member of the crowd – and you’re not. You’re our collaborator. You’re pro-actively involved in the process of science by participating.’ Citizen science is facilitated by modern technology, such as the internet and social media. But its history is much older than that. And it has been particularly fruitful in the field of astronomy.
The 19th century saw many examples of citizen scientists wielding their test tubes, microscopes or barometers in scientific pursuits, mostly upper- and middle-class men and women with the time, money and education to engage in such activities. Their results were often published (in journals such as the English Mechanic and World of Science – and even in prestigious scientific publications such as Nature), but it was really in astronomy that these pursuits were organised into what we’d recognise today as citizen science.
Amateur astronomers equipped with small telescopes have long been able to contribute measurements of the brightness of stars, for example. And for those stars whose brightness varies (unimaginatively known as variable stars), amateurs have provided a valuable service in monitoring their brightness fluctuations. This feeds into the professional field, where the variations can be interpreted in terms of the physical processes taking place inside the star. As long ago as 1911, variable star observers were organised into a cohort of citizen scientists by the American Association of Variable Star Observers. Nowhere was this symbiosis between amateur and professional astronomers more successful than in New Zealand, where a very small number of professionals relied on the wider resources of the nation’s amateur astronomers.
Once again, it highlights the extraordinary value of the amateur community to astronomy, not just in New Zealand, but all over the world. That extends far beyond making a scientific contribution (although astronomy is one of the few sciences in which this is still possible). More significantly, it ensures that there is an accessible and widely available route by which anyone can become involved. The men and women of the amateur community also do much to popularise astronomy, organising lectures, discussion forums, star-parties, star-b-cues and a plethora of other events designed to introduce people to the delights (and pitfalls) of stargazing. For many of these enthusiastic individuals, the ability to carry out citizen science is just the icing on the cake.
CITIZEN SCIENCE OF A RATHER DIFFERENT KIND WAS pioneered by the SETI@home project, in which home computers were mustered into a distributed computing network. This allowed clever software to analyse huge quantities of data from large professional radio telescopes participating in SETI – a collective term for various well-directed searches for extraterrestrial intelligence.
In radio astronomy, the most prolific natural cosmic signature comes from cold hydrogen in space. This pervasive radiation has a characteristic wavelength, and has been studied since the 1950s. After a decade or so of using it in radio astronomy, SETI’s proponents were arguing that the same wavelength might be used by galactic civilisations that wanted to signal to one another. Thus, the first observational SETI programs piggy-backed their monitoring systems onto the receivers being used for conventional radio-astronomy research – a formula that remains in use today. The spiky nature of an anticipated communications signal lends itself to computer detection, an aspect that led in May 1999 to the inauguration of SETI@home. The venture uses the spare capability of idle home computers to trawl through sets of data from piggybacked monitoring systems, reporting results over the internet.
In fact, some radio telescopes do carry out dedicated SETI observations, rather than just piggy-backing onto conventional research programs. A recent high-profile example is the Breakthrough Listen project. The search for extraterrestrial intelligence has been successful in attracting philanthropic funding, no doubt because of its huge popular appeal, and a generous endowment has come from the Breakthrough Foundation, which is an initiative of a Russian investment tycoon by the name of Yuri Milner. Together with the late Stephen Hawking and several other scientific luminaries, Milner kicked off a multi-faceted exploration venture in 2015, of which the first component is Breakthrough Listen. It is, without question, the most ambitious SETI project to date. A US$100 million investment is being used to buy up to a quarter of the total observing time on two major radio telescopes – at the Parkes Observatory in Australia, and the Green Bank Observatory in West Virginia – along with technology enhancements that will also benefit conventional radio astronomy. SETI@home is an integral component of the data analysis.
Despite its longevity, SETI has so far failed to turn up any clear-cut candidates for extraterrestrial communication. Two events stand out: the famous ‘Wow! signal’ of 15 August 1977 (a short burst of radio radiation that prompted the eponymous comment scrawled on the print-out – and is still unexplained) and a signal from the direction of a star known to have an orbiting planet that Russian radio astronomers spotted in May 2015. That one eventually turned out to be coming from a secret military satellite. Ho hum.
WHILE SETI@HOME IS A TASK TO WHICH MACHINE INTELligence is well suited, some large-scale astronomical observational programs are better suited to human pattern-recognition capabilities – and this is where citizen science really comes into its own. One such is the Galaxy Zoo project, founded in Oxford in 2007 by astrophysicists Kevin Schawinski (who we met a couple of pages ago) and Chris Lintott. It was modelled on an earlier NASA venture called Stardust@home, which required participants to visually scan 700 000 sets of images aimed at finding particles of interstellar dust collected and returned by a spacecraft called, yes…Stardust. The task required the judgment of trained volunteers, whose capabilities far outstripped the pattern-recognition software of the early 2000s.
Likewise, Galaxy Zoo is well suited to the capabilities of the human eye and brain, and is currently undertaking the biggest census of distant galaxies yet carried out. Galaxies are huge aggregations of billions of stars, of course, but they come in a wide variety of shapes, sizes, colours and other characteristics. While scientists understand broadly the origin and evolution of galaxies in their various categories, it’s only by studying very large numbers of them that detailed characteristics can be established, and unusual outliers found. There are an estimated two trillion galaxies in the observable Universe, and a significant fraction have been imaged by the world’s large telescopes, making their classification well suited to citizen science.
Galaxy Zoo has had several incarnations throughout its history. Highlights include discovering new categories of galaxies, such as the compact star-forming objects now known as ‘green pea galaxies’ (because that’s what they look like). And it has also led to the identification of some very unusual celestial objects. Who could forget Hanny’s Voorwerp (Hanny’s Object), a rare light echo discovered by Dutch schoolteacher Hanny van Arkel? I’ll discuss light echoes in more depth later on, but Hanny’s Voorwerp is special, a light echo on a grand scale. A galaxy-sized cloud of gas has been ripped from a young galaxy by a passing interloper. But the disturbance has switched on something known as a quasar outburst in the young galaxy, and the black hole at its centre has begun consuming vast quantities of gas from its surroundings, while beaming intense ultra-violet radiation from its poles. The radiation has, in turn, excited the gas cloud, causing it to glow in a manner similar to a light echo. But by now, the quasar has switched off again, so all we see is an innocent-looking young galaxy with a wild-looking blob of glowing gas next to it – Hanny’s Voorwerp.
Stories like that highlight the scientific value of the Galaxy Zoo – nothing quite like the Voorwerp had been seen before. A tenth anniversary conference at Oxford in 2017 celebrated the 125 million galaxy classifications and 60 peer-reviewed scientific papers that had been generated throughout the decade. The science even extended to psychological studies of biases in the perception of galaxy images. But there is also sociological value in the project. An online Galaxy Zoo forum spawned a genuine community spirit. As one prolific contributor, based in the Caribbean, put it, ‘It was love at first sight when I started in Galaxy Zoo.’ The venture is now accessed through a comprehensive web portal called the Zooniverse, which hosts almost 50 different citizen science projects covering a broad range of disciplines.
THUS IT WAS THAT CITIZEN SCIENCE WAS WRIT LARGE IN Stargazing Live. The events I described at the outset of this chapter took place back in 2017, when the show made its debut from Siding Spring Observatory in separate editions for British (BBC) and Australian (ABC) television. Hosted by megastar astronomer Brian Cox, it has segments on professional and amateur astronomy, as well as citizen science and record-breaking attempts for the greatest number of people doing sometimes obscure astronomical things.
As it is a live show, we had to broadcast before dawn in Australia for the BBC version to go to air in its usual mid-evening slot. Early mornings are nothing new to astronomers, but dress rehearsals and studio make-up at 4.30 am were certainly a novelty. And in the end, the broadcasting powers-that-be were delighted with their million-plus audience numbers in both the United Kingdom and Australia. It highlighted the potential of social media to harness the enthusiasm of hundreds of thousands of people in the two countries. It was that more than anything that persuaded them that this was a venture worth repeating annually – in Australia at least.
In addition, the BBC version of the show highlighted a uniquely Australian citizen science project – the Desert Fireball Network’s ‘Fireballs in the Sky’. While the network itself consists of 50 automatic cameras constantly scanning the night skies of Western Australia and South Australia for bright meteors (shooting stars), its results are augmented with observations by citizen science participants. Together, these data allow fireballs to be tracked in three dimensions, raising the possibility that a meteorite might be recovered from the ground for scientific analysis. The project is led by Phil Bland of Curtin University, and the BBC interviewed Gretchen Benedix, the project’s mineralogist/petrologist.
The two real-time citizen science projects featured in the 2017 Stargazing Live programmes addressed two of the highest profile issues in contemporary astronomy. The BBC highlighted the search for Planet Nine, a hypothetical world orbiting the Sun somewhere around 20 times further away than Neptune. More on that later. The project compared images gathered by the Australian National University’s SkyMapper telescope at Siding Spring, with three separate photos of a given area of the sky, taken on different dates, being inspected to find slowly moving objects. A flurry of excitement ran through the Stargazing Live set when, during the final show in the series, a sequence of images was found that seemed to show an object in exactly the right part of the sky with the right amount of motion between its images. Sadly, it turned out that images of three different known asteroids had been captured, rather than three images of the same slowly moving object. Planet Nine thus remained elusive on Stargazing Live but, as we will see later, the hunt is still very much in progress.
A more successful outcome favoured the ABC’s 2017 Stargazing Live project. Here, the citizen science challenge was that epic romp through data from NASA’s Kepler spacecraft, which resulted in young Andrew Grey from Darwin hitting the exoplanet jackpot with his four planets. As the project’s leader, Chris Lintott, pointed out, the discovery was scientifically important because there were only one or two other known solar systems where the planets were packed together so close to their parent star. And that might tell astronomers more about how planets form – one of the hot topics in current studies. For Chris, Andrew, and the millions of other ordinary people involved with citizen science projects around the world, this is a truly exciting and successful way to push back the frontiers of knowledge.
AND FOR ME, TOO, 2017’S STARGAZING LIVE BROUGHT SOME moments of unexpected excitement, including my formal introduction to asteroid no. 5691 live on the ABC version of the show, courtesy of the Las Cumbres Observatory’s 2-metre telescope at Siding Spring. Even in such a large instrument, this perfectly ordinary – if not a little boring – main-belt asteroid looks like nothing more than a point of light. Since 2004, however, it has sported a name that seems somehow familiar – 5691 Fredwatson. Seeing that moving dot on the TV monitor definitely brought a sparkle to my eyes.
And finally, Stargazing Live opened those same eyes to something citizen science excels at, and has huge potential for the future of science generally. That’s in the way it engages youngsters, giving them an opportunity both to learn and to contribute real knowledge via cleverly designed citizen science projects with appealing web interfaces. From palaeontology to stargazing, from spotting wildlife to tracking light pollution, there are projects for every interest. At a time when we need science more than ever to tackle environmental threats, this is a hopeful sign. Nothing less than the future of humanity is at stake. No pressure, kids.
