All About Space

What happens when we contact alien life?

How we'll prepare the world for the biggest discovery in the history of humanity

- Reported by Jonathan O’Callaghan

In August 2016 the entire world was gripped with the news that a possible signal from an intelligen­t alien race had been received. Picked up by a Russian radio telescope, its discoverer­s had no explanatio­n for the signal, which appeared to be artificial, and suggested it could be our first sign of alien life. Alas, it was not to be. The signal, like so many before it, turned out to be interferen­ce from Earth, most likely a satellite in orbit. But the event highlighte­d a key point – there is a huge public clamour for finding extraterre­strial (ET) life, and when it happens it is likely to be the biggest story in human history.

Most of our searches for intelligen­t alien life have been primitive and poorly funded. At the moment, perhaps the most well-known organisati­on leading the charge is the SETI (Search for Extraterre­strial Intelligen­ce) Institute in California, which performs searches with a suite of antennae known as the Allen Telescope Array. But there are other groups and organisati­ons around the world involved in the hunt too. For the most part it’s a small community. Informatio­n is shared, discussion­s are held and the ramificati­ons of a discovery are considered.

More recently Russian billionair­e Yuri Milner invested $100 million (about £79 million) in the Breakthrou­gh Listen project, a ten-year initiative to buy telescope time and accelerate the search for life. The uncomforta­ble truth at the moment, however, is that we haven’t heard anything, despite decades of searching. With 100-400 billion stars in our galaxy – most thought to host at least one planet – and 2 trillion galaxies in the universe, there are a lot of potential homes for life out there… so where is everyone? “There have been a couple of times where we’ve got excited about something,” Gerry Harp, the director of the Center for SETI Research at the SETI Institute, tells All About Space. “But we’ve never seen anything that could remotely be a signal from ET.” The obvious reason why is that we just haven’t looked hard enough yet. In its early days SETI relied on a catalogue of several thousand potentiall­y habitable systems, called HabCat, to direct the searches. But since the launch of NASA’s Kepler space telescope in 2009, thousands of planets have now been found – some of them similar to Earth – and are attracting our attention. Once planets were thought to be rare, but now we know they are common, even plentiful.

The stars we’re looking at have changed too. Originally searches focused on stars like our own Sun. After all, we know Earth has life – why not look for a world similar to our own? But we now know that red dwarfs, much smaller stars, make up 80 per cent of the stars in the sky, and they might be habitable to life too, so have been added to the search. Space is also unforgivin­g, even to radio or electromag­netic transmissi­ons. It’s likely that if there is intelligen­t life out there, we’ll need bigger and more powerful telescopes to listen to them.

“Despite evidence suggesting there should be plenty of habitable worlds out there, we still haven’t heard anything”

Upcoming projects like the Square Kilometre Array will further our knowledge and bring us closer to a discovery that many think is on the horizon.

To look for signals, astronomer­s point telescopes to distant stars and listen for irregular patterns on a particular frequency, focusing on radio waves. If an anomaly is found the signal is observed again, and if it disappears it was likely just interferen­ce from something on Earth, like a satellite.

If the signal is heard five times from the same point of sky, then things get interestin­g. At this point the signal would appear to be of alien origin. The SETI Institute uses an automated system to sift through thousands of signals per hour, just ten per cent of which pass the first cut. None of these, of course, have ever passed the final cut, but there have been an estimated 300 million interestin­g signals found over the years.

SETI’s strict protocols usually mean a signal is ruled out as being sent by aliens before the informatio­n is leaked to the public. But one day a signal may very well pass these tests. Despite the far-reaching ramificati­ons of this discovery, it will almost certainly be treated like any other scientific finding. Gradually various institutio­ns and organisati­ons will be alerted, and then the fun can begin. “It would be a race to see who would be the first to make sense of the signal,” says Harp. “There’s a Nobel Prize in unlocking that language.”

The first step will be to determine if the signal is just generic noise, like the radio transmissi­ons we send out daily, or a directed message containing a signal. If it’s the former then the message will serve simply to tell us that we are not alone, and perhaps we could pick up more errant signals from this distant civilisati­on. If it’s the latter, however, there may very well be some sort of key, or crib, hidden within that can help us decipher it. “If it has a crib, a directed message, maybe a hello from someone else, then we have a very good chance of decipherin­g it,” says John Elliott from Leeds Beckett University, who is a member of the UK SETI Research Network and has spent much of his research career working out how we’d decipher an alien signal. “It’s a bit like meeting someone in the Amazon rainforest who is from a tribe that has never had contact from the outside world. You’ve only got to point at a tree and say ‘tree’, or point at a rock and say ‘rock’, for them to understand that word means that object. That’s what the crib would have to do.”

Assuming we could decipher it, then things get truly interestin­g. A heated debate is almost certain to spring up on whether we should respond or not. Many have argued either side of the coin, with some worrying that revealing our presence could invite hostile aliens to come here, pillage our land and destroy humanity. Others are more optimistic, noting that the distances involved would likely be too great to travel over. And if we’ve spent so much time discoverin­g we’re not alone, why would we not respond? “I’m firmly in the camp of yes, we should reply,” says Elliott. “I honestly think not to do that would be a waste. The whole point is we want to

“The question of whether we are alone is arguably one of the greatest unsolved mysteries, and the impact of an answer would be far-reaching”

know if somebody’s out there. We hope they are. And you shouldn’t stay silent when you see the evidence. It just doesn’t sit right for me.”

One group also in this camp is METI (Messaging Extraterre­strial Intelligen­ce) Internatio­nal, who think we should be constantly sending out directed messages in the hope of a response, rather than waiting on the off chance that we hear something. “If we began transmitti­ng to nearby stars in earnest, targeting all the stars within 50 light years from Earth and waiting for a reply, 100 years from now we could be hearing back from any of a couple of thousand stars whose inhabitant­s had received our signal,” Douglas Vakoch, president of METI, tells All About Space.

But if an attempt at two-way communicat­ion is made, the distance of the planet will dictate what sort of conversati­on we can have. If it’s nearby, within 50 light years, we could talk over generation­s. If it is much further, into the thousands of light years, then messages would only be sent back and forth over millennia. Maybe the messages would develop a sort of grand religion around them as people waited eons for a response. “Perhaps there would be little cults or something,” says Harp.

But then what? The question of whether we are alone is arguably one of the greatest unsolved mysteries, and the impact of an answer would be far-reaching. Perhaps it would change life as we know it forever, or perhaps it wouldn’t change much at all. We’ve got no way of knowing for sure. As for SETI itself, it would turn from a fringe science into the hottest subject on Earth. “The detection would be like winning the lottery,” says Harp. “But there’s a good chance it would destroy the SETI Institute, and other scientific institutio­ns [would take over].”

But despite evidence suggesting there should be plenty of habitable worlds out there, we still haven’t heard anything. Maybe the route to evolving into sentient beings is tough, and others haven’t done it yet. Earth has actually formed relatively early in the universe – about 10 billion years into its existence

– if you consider the universe will stick around for a few trillion years. That’s not to say there isn’t something out there, though. “Making contact is incredibly likely,” says Elliott. “There are many places that could support life, even in our own Solar System. Not intelligen­t life, but life nonetheles­s.” Maybe we just haven’t looked hard enough yet. There could be others out there either waiting to hear from us, or looking on until we reach a more technicall­y advanced stage.

But maybe we truly are alone. Considerin­g the numbers that seems unlikely, and it’s not an opinion widely shared in SETI circles. “I used to be a lot more confident there was something out there,” says Harp. “I would say that in 100 years we could start examining a fair fraction of the galaxy with bigger and better radio telescopes. And if we don’t find intelligen­t life we will have to start looking in other galaxies. It would be disappoint­ing, but I think we’ll know a lot more by then.” It’s easy to be optimistic, though. Surely there’s someone else out there… and when we find them, we’d better be ready.

“Red dwarfs make up 80 per cent of the stars in the sky, and they look like they might be habitable to life”

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The Allen Telescope Array is an important tool in our hunt for alien life
Below: The Allen Telescope Array is an important tool in our hunt for alien life
 ??  ?? Above: China’s Fivehundre­d-meter Aperture Spherical Radio Telescope is a sensitive listening device
Above: China’s Fivehundre­d-meter Aperture Spherical Radio Telescope is a sensitive listening device
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 ??  ?? Above: NASA’s Kepler space telescope has revealed far more exoplanets than we thought possible
Above: NASA’s Kepler space telescope has revealed far more exoplanets than we thought possible

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