Alien life will be found but what?

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Not if aliens are out there but what are they ... ET with child actor Henry Thomas from 1982 movie E.T. the Extra-Terrestrial. Source: News Limited

SCIENCE fiction is running out of space. The hunt for alien life is heating up. Now, it's no longer a question of "if" we will find life out there. It's a question of "what".

Land and space based telescopes scouring our skies have in the past few years produced 21 planets that are possible contenders for containing life. That's out of 1793 planets detected orbiting distant stars so far.

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The very existence of these planets, which fit within the band of conditions ranging from the barren wastes of Mars through to the frigid oceans under the surface of the moon Europa, prompted NASA earlier this year to make a startling prediction.

"I think in the next 20 years we will find out if we are not alone in the universe," NASA Astronomer Kevin Hand told an awe-struck media conference in June.

A colleague took it one step further.

"Imagine the moment that the news breaks we've discovered Earth 2.0," Matt Mountain, the director of the Space Telescope Science Institute, told the panel.

"Imagine the moment the whole world wakes up to the news our long loneliness in time and space may have ended. We may no longer be alone in the universe."

We can find evidence of that life through a variety of means — once we have sensors sensitive enough. Those tools — such as the James Webb space telescope, the Square Kilometre Array and the Giant Magellan Telescope — are now starting to come online.

They'll be seeking the telltale "fingerprints" of life etched into the starlight reflected off a planet's atmosphere — such as the particular forms of oxygen and methane which it is believed only processes such as photosynthesis can create.

"They'll be looking for the key ingredients, chemicals, for life like water, oxygen and methane — even pollutants from industry like CFCs," says Australian astrophysicist Dr Alan Duffy, Research Fellow at the Swinburne University of Technology.

And, like the famous SETI project which began in the 1960s, they'll be turning refined electronic ears skyward to pick up any garbled radio chatter that may be wafting our way.

So what do they expect to find?

Knows what aliens will want ... Astrophysicist Dr Alan Duffy. Picture: Karin Calvert Source: News Limited

WHAT IS LIFE ANYWAY?

Life may prove to be common in the heavens. But intelligent life is hard enough to find here on Earth.

Slime is life. It's the single-celled foundation of the vast bulk of life on our own planet.

Based on our own history, it's also likely to be among the most easily detected on alien planets. After all, it was a hemisphere-wide infestation of tiny fern algae which sucked the carbon out of our own atmosphere over the course of millions of years, replacing it with life-giving levels of oxygen and cooled our world to a more habitable condition.

"We know that we can look for some basic signs of life based on what we know about life on Earth," molecular biologist Upulie Divisekera of Monash University says.

Some of it is plain strange.

Some forms of life are built around different chemicals. Some can survive on the ocean floor near volcanic vents, harvesting nutrients from the planet's core. Others, like one newly discovered species of bacteria, actually survive by harvesting electrons — bypassing nutrients altogether.

"So while we look for traits of life that match ours, it's possible that in other solar systems we may have to look for different signals, or find that life is very different," Ms Divisekera says. "But we already have an idea of what strange forms of life may exist at the extremes on Earth. Life on other planets may not use the same biochemistry, and that's intriguing and exciting to think about."

But it's alien civilisations all are secretly hoping to find.

We may have already come close: On August 15, 1977, a strange 72-second radio signal from deep space prompted a "wow" response.

Sourced from within the Sagittarius constellation, the signal does not match any known natural event.

However, as it has only been detected once — and because some unknown "contaminating" source has not been ruled out — it remains just a prominent subject of speculation.

HOT BODIES

Will they be this cute ... A green alien cartoon Picture: Supplied Source: Supplied

This isn't the blue or green body-painted actors that grace shows such as Star Trek, Star Wars and Guardians of the Galaxy.

It's about the same industrial waste which threatens our own atmosphere. It's about the massive amounts of energy space-faring species would have to expend.

The US Center for Exoplanets and Habitable Worlds have launched a project called G-HAT, Glimpsing Heat from Alien Technologies.

Essentially, they're looking for unusually high amounts of infra-red radiation in unexpected places. This "out of place" heat could be a clear marker of an alien civilisation's industrial efforts.

They're doing this by analysing data a satellite called WISE, the Wide-field Infrared Survey Explorer, which has mapped the entire sky in the infra-red.

But it's not an easy task.

"Distinguishing that waste heat from ordinary astrophysical dust will be very difficult in many cases, and proving it's of alien origin will be even harder, G-HAT team leader Jason Wright said.

COLD HEARTS

We're not talking Darth Vader, the predatory Aliens of H.R. Geiger's twisted imagination, nor even the immune-system challenged Martians of the 1900s novel War of the Worlds.

We're talking about the potential for life right under our noses: The ice moons of our own solar system.

It could also help explain why life has so far proven so hard to detect. Not even the best telescope will sense something living in a salty ocean buried under kilometres of ice.

This is what we're looking for now.

"The frozen moons in our own solar system have blasted water into space, these geysers offer us a chance to sweep through the plume and sample these subsurface oceans without having to drill through kilometres of ice. There may even be a frozen alien 'fish' blasted into orbit," Dr Duffy says.

While rovers wheel around the dead, dusty deserts of Mars for evidence of likely long-dead life, astronomers are turning their eyes towards Europa.

It's what NASA touts as its next great project.

The shiny but fractured moon of Jupiter has gained a lot of attention lately. Basking in the glow of its gas giant parent, the ice moon shows evidence of internal heating which may have melted salty water out of the thick ice crust which covers its surface — and created conditions ideal for life.

It's a concept seemingly proved as recently as last month after a whole ecosystem of microbial life was found living in lakes deep under the ice of Antarctica.

Funding and ideas for establishing how to explore below Europa's surface are being sought now, with the goal of launching a probe to the mysterious world by the middle of the century.

CREATURES OF LIGHT

No, this isn't about those transcendental super-intelligent shades of the colour blue.

It's more about the strategy of how to find them.

Life has a deep impact. It alters the worlds it inhabits. Key chemicals in the atmosphere change. And it's these chemicals — and the proportions in which they exist — which astronomers hope will give us our first strong clue of life out there.

The atmospheres of more than 30 worlds have so far been examined in detail. These initial results have taught scientists to expect the unexpected: Water in the clouds of huge Jupiter-like gas planets and intense greenhouse worlds significantly larger than Venus are just part of the mix.

But more and more worlds will come under our direct gaze as new and more powerful telescopes take to the skies.

Again, the challenge is immense.

The light reflected from the atmospheres of these planets will be as dim as the most distant galaxies ever found by the Hubble Space Telescope. The catch: They're sitting alongside stars that will be up to 10 billion times brighter than the planet itself.

"Trying to take an image of an Earth-like world next to its parent star is like looking for a firefly next to the glare of the MCG's floodlights. Oh, and you're in Perth. It's tough," Dr Duffy says.

Telescopes capable of achieving this are being designed now. But none have yet been built.

WHAT WOULD THEY LOOK LIKE?

What will an alien look like ... A scene from 19882 movie E.T. the Extra Terrestrial. Source: News Corp Australia

Until recently, such speculation has specifically been the realm of science fiction.

But even here, many authors have tried hard to "get real".

"I don't believe an alien species from an entirely different biochemical foundation would happen to turn out with two arms, two legs, two eyes, ears, nostrils…," science fiction author Kevin Anderson recently told the magazine Popular Mechanics.

"But, for intelligence one would assume brain capacity, and therefore the body would need some sort of protective mechanism for the vital brain — an exoskeleton, a skull, something like that. "

It's a line of thinking reflecting that of real evolutionary biologists.

Intelligence needs sensory input. We have eyes, but there is no reason it couldn't be something akin to a bat's sound echo location trick.

We assume intelligence would need to build tools. To do this, they need limbs or appendages (tentacles could be as effective as opposable thumbs) capable of great dexterity.

They would also need the ability to pass on the knowledge gained by each generation. For this, they would need some form of rapid communication, be it by speech, pheromone or even patches of light on their skin.

They could live on their world's surface. They could live under it. They could even live above it — drifting on the winds, so long as a food-source was ready at hand.

The most common serious analogy for alien intelligent life is found in our own oceans: The octopus.

They have proven to be startlingly intelligent, solving complex problems and learning procedures at a level previously thought limited to humans. Compared to our own, their environment is distinctly alien. Not only are they wet, some octopi live under immense pressure — not unlike the effect of a world with stronger gravity or dense gases.

The only catch is fire: It is commonly accepted that this basic energy source is necessary for the seeds of technology to germinate in an intelligent mind.

WHY HAVEN'T WE FOUND THEM YET?

Icy surface with cracks, ridges and "chaotic terrain" ... Europa's Hidden Ice Chemistry. Picture: NASA/ Flickr Source: Flickr

This one has many scientists stumped.

By the numbers, we probably should have found signs of at least one spacefaring civilisation by now.

But we haven't.

It's why science is divided into two distinct camps on the subject: Those who insist "We are not alone", and those who say "We might be".

It's an impasse which would be broken the instant we find a trace of life which has evolved independently elsewhere — be it on Europa, Mars or a world circling a completely different star.

Odds are it's out there. After all, statistically, astronomers have determined that every star in our galaxy is likely to be paired with a planet. And rocky planets like our own seem increasingly common.

"Our own galaxy has 100 billion stars, and our universe has upwards of 100 billion galaxies, making the chance for life elsewhere seem inevitable based on sheer probability," MIT planetary scientist Sara Seager wrote last month.

"When you look in the night sky every star on average has a planet," Dr Duffy affirms. "One in five has a planet similar in size to Earth. You'd be a brave gambler to bet against those odds that all are empty of life."

Our Sun is a young one. Others have existed for several billion years more.

So why aren't ancient aliens knocking at our door?

Perhaps they simply cannot be bothered. Perhaps they've all wiped themselves out. Or perhaps they're there — and we're simply to juvenile to recognise what we're seeing.

But what about more basic life?

Is Earth's complex life the result here only because of a highly improbable and complex specific sequence of events? Or are the fundamental building blocks of life so common that it can flare up virtually anywhere?