Detecting life

Detecting life

Map of detected habitable planets


Telescopes and sensors


Kepler space telescope has done some incredible work.

Histogram of Exoplanet Discoveries - the yellow shaded bar shows newly announced planets including those verified by the multiplicity technique (February 26, 2014).


Wikipedia, Kepler (spacecraft)

On February 13, 2014, a few hundred additional planet candidates were announced residing around single planet systems. Several of them were nearly Earth-sized and located in the habitable zone. (

On February 26, scientists announced that data from Kepler had confirmed the existence of 715 new exoplanets. A new statistical method of confirmation was used called “verification by multiplicity” which is based on how many planets around multiple stars were found to be real planets. This allowed much quicker confirmation of numerous candidates which are part of multiplanetary systems. 95% of the discovered exoplanets were smaller than Neptune and four, including Kepler-296f, were less than 2 1/2 the size of Earth and were in habitable zones where surface temperatures are suitable for liquid water.(

On March 2014, a study found that small planets with orbital periods of less than 1 day are usually accompanied by at least one additional planet with orbital period of 1-50 days. This study also noted that ultra-short period planets are almost always smaller than 2 Earth radii unless it is a misaligned hot Jupiter.(

Kepler data also helped observe and understand supernovae; measurements were collected every half hour so the light curves were especially useful for studying these types of astronomical events.(

On 17th April, Kepler team announced a discovery Kepler-186f, the first nearly Earth-sized planet located in the habitable zone. This planet orbits around a red dwarf. (

A more updated graph is below



With larger telescopes, the answer to the life question looms larger.

We need bigger telescopes and sensors to make out the detail on exoplanets in the habitable zones. Perhaps one that can measure starlight absorption across continents, that may signal extensive plant (or similar) life.

Be at the forefront of that when it happens.

Ellen Stofan, Reddit AMA

With the James Webb Space Telescope, we will look at the atmospheres of planets around other stars- taking a big leap towards finding habitable planets! JWST launches in 2018- so stay tuned! -- Ellen

James Webb Telescope

From <>

So what will it take to identify a ‘live’ planet, one with an Earth-like mix of continents and seas, not too wet, not too dry? Given the range of possible worlds out there, there must be many like ours – but how will we find them? The James Webb Space Telescope (JWST) will dominate astronomy once it starts its five-to-10-year mission in 2020; it will be able to analyse the atmospheres of giant, Neptune-size exoplanets, and might even spot some ‘Super Earths’ – planets with masses two to 10 times that of Earth’s. But it will be too nearsighted to make out the atmospheres, let alone oceans, of such worlds.

‘It’s very difficult to look at something so small – the size of Earth passing in front of its star – and see that little sliver of atmosphere,’ says Meinke, the JWST deputy project scientist. ‘There are plans for future telescopes that should be able to do that, and I will make this prediction: I think we’ll be able to do that within my professional career. But Webb won’t be able to confirm water on a terrestrial-type planet.’

Telescopes capable of directly imaging the oceans and land masses of another world are probably at least a couple of decades away. And even then the resolution will likely be limited to a pixel or two for the entire planet. So here’s how one of the most portentous discoveries in the history of science – our first direct look at a world such as our own – might unfold: the colour of a single pixel will cyclically shift from blue to brown as a faraway planet pirouettes, alternately exposing its lands and seas to our eyes.


Robin McKie, The telescope big enough to spot signs of alien life on other planets

Engineers are about to blast away the top of a Chilean mountain to create a site for the European Extremely Large Telescope. It will allow us, for the first time, to directly observe planets outside the solar system


An artist's impression of the European Extremely Large Telescope (E-ELT).

Cerro Armazones is a crumbling dome of rock that dominates the parched peaks of the Chilean Coast Range north of Santiago. A couple of old concrete platforms and some rusty pipes, parts of the mountain's old weather station, are the only hints that humans have ever taken an interest in this forbidding, arid place. Even the views look alien, with the surrounding boulder-strewn desert bearing a remarkable resemblance to the landscape of Mars.

Dramatic change is coming to Cerro Armazones, however – for in a few weeks, the 10,000ft mountain is going to have its top knocked off. "We are going to blast it with dynamite and then carry off the rubble," says engineer Gird Hudepohl. "We will take about 80ft off the top of the mountain to create a plateau – and when we have done that, we will build the world's biggest telescope there."

Given the peak's remote, inhospitable location that might sound an improbable claim – except for the fact that Hudepohl has done this sort of thing before. He is one of the European Southern Observatory's most experienced engineers and was involved in the decapitation of another nearby mountain, Cerro Paranal, on which his team then erected one of the planet's most sophisticated observatories.

The Paranal complex has been in operation for more than a decade and includes four giant instruments with eight-metre-wide mirrors – known as the Very Large Telescopes or VLTs – as well as control rooms and a labyrinth of underground tunnels linking its instruments. More than 100 astronomers, engineers and support staff work and live there. A few dozen metres below the telescopes, they have a sports complex with a squash court, an indoor football pitch, and a luxurious 110-room residence that has a central swimming pool and a restaurant serving meals and drinks around the clock. Built overlooking one of the world's driest deserts, the place is an amazing oasis. (See box.)

Now the European Southern Observatory, of which Britain is a key member state, wants Hudepohl and his team to repeat this remarkable trick and take the top off Cerro Armazones, which is 20km distant. Though this time they will construct an instrument so huge it will dwarf all the telescopes on Paranal put together, and any other telescope on the planet. When completed, the European Extremely Large Telescope (E-ELT) and its 39-metre mirror will allow astronomers to peer further intospace and look further back into the history of the universe than any other astronomical device in existence. Its construction will push telescope-making to its limit, however. Its primary mirror will be made of almost 800 segments – each 1.4 metres in diameter but only a few centimetres thick – which will have to be aligned with microscopic precision.

It is a remarkable juxtaposition: in the midst of utter desolation, scientists have built giant machines engineered to operate with smooth perfection and are now planning to top this achievement by building an even more vast device. The question is: for what purpose? Why go to a remote wilderness in northern Chile and chop down peaks to make homes for some of the planet's most complex scientific hardware?

The answer is straightforward, says Cambridge University astronomer Professor Gerry Gilmore. It is all about water. "The atmosphere here is as dry as you can get and that is critically important. Water molecules obscure the view from telescopes on the ground. It is like trying to peer through mist – for mist is essentially a suspension of water molecules in the air, after all, and they obscure your vision. For a telescope based at sea level that is a major drawback.

"However, if you build your telescope where the atmosphere above you is completely dry, you will get the best possible views of the stars – and there is nowhere on Earth that has air drier than this place. For good measure, the high-altitude winds blow in a smooth, laminar manner above Paranal – like slabs of glass – so images of stars remain remarkably steady as well."

The view of the heavens here is close to perfect, in other words – as an evening stroll around the viewing platform on Paranal demonstrates vividly. During my visit, the Milky Way hung over the observatory like a single white sheet. I could see the four main stars of the Southern Cross; Alpha Centauri, whose unseen companion Proxima Centauri is the closest star to our solar system; the two Magellanic Clouds, satellite galaxies of our own Milky Way; and the Coalsack, an interstellar dust cloud that forms a striking silhouette against the starry Milky Way. None are visible in northern skies and none appear with such brilliance anywhere else on the planet.

Hence the decision to build this extraordinary complex of VLTs. At sunset, each one's housing is opened and the four great telescopes are brought slowly into operation. Each machine is made to rotate and swivel, like football players stretching muscles before a match. Each housing is the size of a block of flats. Yet they move in complete silence, so precise is their engineering.

Building the four VLTs, which have been named Antu (Sun), Kueyen (Moon), Melipal (Southern Cross) and Yepun (Venus) in the language of Mapuche people of Chile, was a formidable challenge, needless to say. Each has a giant mirror that is 8.2 metres in diameter but only 17cm thick: any thicker, and the mirror would be too heavy to move and point. Such thinness leaves the mirrors liable to deform as temperatures and air pressure fluctuate, however, and so each has 150 actuators fitted to its unpolished side. These push the mirrors to keep them within a few billionths of a centimetre of their proper shape. In addition, ESO astronomers use a laser-based system known as adaptive optics to measure turbulence in the upper atmosphere and to change each telescope's internal mirror configuration to compensate for any disturbance they can measure.

The result is a cluster of astronomical devices of incredible power and flexibility, one that has been involved in an astonishing number of critically important discoveries and observations over the past decade, as ESO astronomer Olivier Hainaut explains. "Perhaps the VLT's most spectacular achievement was its tracking of stars at the centre of the Milky Way. Astronomers followed them as they revolved around… nothing. Eventually they were able to show that something incredibly small and dark and massive lay at the centre of this interstellar waltz. This was the first time, we now know, that scientists had directly observed the effect of the supermassive black hole that lies at the heart of our galaxy."


The Milky Way seen from the Paranal Observatory in Chile. Photograph: National Geographic Image Collec/Alamy

The VLTs also played a key role in providing observations which showed, from the behaviour of distant supernovae, that the expansion of the universe was actually accelerating thanks to the action of a force now known as dark energy. This discovery later won Saul Perlmutter, Brian Schmidt and Adam Riess the 2011 Nobel prize for physics. And in 2004 the telescopes were used to make a direct observation of an exoplanet – a planet that orbits around a star other than our Sun. It was another astronomical first. Until then scientists had only been able to infer the existence of exoplanets from the way they affected the movement of their parent star or its light output. "This was history-book material, a discovery of the same quality as Galileo's drawings of the mountains on the moon or the satellites of Jupiter," says Hainaut.

These discoveries have only whetted astronomers' appetites for more, however. Hence the decision to build the £800m E-ELT – whose British funding will come through a £88m investment from the UK Science & Technology Facilities Council. Engineers have now completed a road to the mountain from Paranal and on 16 June are set to begin blasting to remove the top from Cerro Armazones. Then they will start to build the E-ELT using 798 hexagonal pieces of mirror to create a mammoth device that will be able to collect a hundred million times more light than the human eye. When completed in around 2025, the 2,700-tonne telescope will be housed in a 74 metre high dome and operated by astronomers working 20kms away in Paranal. It will be the world's biggest eye on the sky.

An indication of the E-ELT's potential is provided by ESO astronomer Linda Schmidtobreick. "There are fundamental issues that only a telescope the size of the E-ELT can resolve," she says. "Its mirror will have a surface area 10 times bigger than any other telescope, which means it will take a 10th of the time to collect the same amount of light – ie the same number of photons – from an object compared with these other instruments."


The astronomers' residence: 'As accommodation goes, it's as exotic as you can get.'

For Schmidtobreick, this ability to collect light quickly is crucial to her research. She studies stars known as cataclysmic variables: pairs of stars in which one is pulling vast amounts of gas, mainly hydrogen, from its companion, a process that can trigger gigantic thermonuclear eruptions, sometimes within 30 seconds or so. "With current instruments, it can take minutes or hours to collect light from these objects, which is too long to resolve what is happening," says Schmidtobreick. "But with the E-ELT, we will be able to study many, many more cataclysmic variables because we will be able to collect significant amounts of light from them in seconds rather than minutes or hours and so will be to resolve their behaviour."

Simone Zaggia, of the Inaf Observatory of Padua, is another frequent visitor to Paranal and has a very different reason for backing the E-ELT. He believes it will play a vital role in the hunt for exoplanets – in particular, exoplanets that are Earth-like and which could support life. "At present, our biggest telescopes can only spot really big exoplanets, giants that are as big as Jupiter and Saturn," he says.

"But we really want to know about the smaller worlds that make up the solar systems in our galaxy. In other words, we want to find out if there are many Earth-like planets in our part of the universe. More importantly we want to find out if their atmospheres contain levels of oxygen or carbon dioxide or methane or other substances that suggest there is life there. To do that, we need a giant telescope like the E-ELT."

This point is backed by Gilmore. "We can see exoplanets but we cannot study them in detail because – from our distant perspective – they appear so close to their parent stars. However, the magnification which the E-ELT will provide will mean we will be able to look at them directly and clearly. In 15 years, we should have a picture of a planet around another star and that picture could show its surface changing colour just as Earth does as the seasons change – indicating that vegetation exists on that world. We will then have found alien life."

A walk down the alleyway that leads from Paranal observatory's entrance gate into its astronomers' residence produces one of the most striking changes in surroundings you can experience in a few footsteps. Outside the air is parched and the ground bleached by sunlight from a sky that is hardly ever troubled by clouds. Push through the double swing doors and you enter a rainforest – and a path that leads down through towering ferns and tropical plants until you reach a swimming pool in the residence's lowest level. As accommodation goes, it's as exotic as you can get - though hedonism was far from the minds of the architects when they designed it.

To battle the arid conditions of the air at 8,600ft-high Paranal, they wanted a way to keep it moist and fresh for the scientists staying there. The answer was a swimming pool and an indoor tropical garden that is constantly watered with supplies imported by trucks from the coast every day. Moist air from the pool and garden then circulates around the rest of the residence. The result is a building that is remarkably airy and light – until 7pm when, every night, all openings and windows, including the vast glass dome over the pool, are closed and shuttered automatically to prevent any chink of light from affecting observations made on the mountain top.

The scale and style of Paranal and its residence is extraordinary and movie producers have fallen over themselves in their attempts to film it. Most have been turned down – with the exception of the 2008 Bond film,Quantum of Solace, whose final scenes were filmed here. (In contrast the last X-Men film was turned down flat because its producers wanted to fly helicopters near the observatory's precious telescope complex.) Given the vast cost of building and running Paranal, filming was not allowed to disturb its tight observing schedule. "I was woken up by the sound of someone repeatedly jumping on to the balcony in the room next to mine," one astronomer recalls. "It turned out to be the actress Olga Kurylenko - who plays the film's heroine Camille. It was quite a shock. I mean you don't get that sort thing happening at other observatories."

Sending and detecting signals

Space is very, very large

Perhaps we have not heard from any ET's is exactly because space is so large. Communication and activity happen in articulate, precise stabs/beams, which go straight through the great emptiness without hitting anything in the middle. Like Earth.

If there was other spacefaring life, the chances of them coming into contact with our signals are very small. There are other ways of detecting life on a planet though, such as energy absorption over continents, which suggests plant life.


This is the area in which we have mapped planets:

[I've had a look at this, I think that the area depicted is about 3000 light years, not 300.]


If we can do that from earth, it's not inconceivable that a highly advanced civilization has the entire galaxy mapped, and sites for potential life under watch. Maybe they just sit back and wait for the signals to come to them (this would take hundreds of thousands of years). Or, perhaps they have sensors installed to detect intelligent life emerging (if their benefits of such sensors are greater than their costs) that use FTL technology to beam the data back.

Why would they do this? To take note of potentially emerging rivals, or allies, or perhaps some kind of biological resource, or perhaps for the scientific curiosity of life emerging.

It seems that the maximum range that we can detect or send out using our own technology is 1,000 light years. Signals erode to static, and the more directions they are sent in, the faster they erode.

There is also the possibility of messages being sent to us, from some location. It may make more sense to gather information before you reveal your position though.

Stephen Hawking: I think it likely that we are the only civilization within several hundred light years, otherwise we would have heard radio waves. The alternative is that civilizations don’t last very long, but destroy themselves.

The type of signal may be totally different


Signals could hypothetically be sent in the form of bursts of neutrinos, which are subatomic particles that pass through ordinary matter unimpeded. They would be able to pass through interstellar gas, dust, background radiation, and even stars without being obscured. We are only beginning to develop the technology required to detect them.

The HD 164595 signal

Seth Shostak, A SETI Signal?

Now note that we can work backwards from the strength of the received signal to calculate how powerful an alien transmitter anywhere near HD 164595 would have to be. There are two interesting cases:

(1) They decide to broadcast in all directions. Then the required power is 1020 watts, or 100 billion billion watts. That’s hundreds of times more energy than all the sunlight falling on Earth, and would obviously require power sources far beyond any we have.

(2) They aim their transmission at us. This will reduce the power requirement, but even if they are using an antenna the size of the 1000-foot Arecibo instrument, they would still need to wield more than a trillion watts, which is comparable to the total energy consumption of all humankind.

Both scenarios require an effort far, far beyond what we ourselves could do, and it’s hard to understand why anyone would want to target our solar system with a strong signal. This star system is so far away they won’t have yet picked up any TV or radar that would tell them that we’re here.

The hunt for amino acids

The mouse and rat chemical DNA is symbiotic with our DNA. The cockroach too. They will go where we go. If we land on other places, they will too. Then the bacteria on them will infiltrate even further. We carry all these species, these replicating DNA molecules, with us wherever we go. Around other dominant self replicating molecules, there will be others that latch onto its every step. Discovering traces of other self replicating species means that the dominant one had reached that place at some point . You're closing in on them.

If there were amino acids on the rocks, that means we might be within the sphere of another dominant space travelling species. Or id they werent it may mean that life sprung up here on its own.

Will be interesting to see what's on Titan. Mars too.

The distances between the extra solar planets is way too big. You'd have to literally invent teleportation to get around.

Uv radiation has probably killed the amino acids on the asteroids now. The only evidence will probably be on moons and planets safe from tr uv and harshness of space. If there's no evidence, then that prob means that life sprung up roght here on earth. That's got lonely possibilities. If it does, then we may either be within another space daring species sphere, or the universe dispenses amino acids all throughout the place. The likelihood of the latter depends on how difficult amino acids are to form in the conditions of early space.

Hunt the forms of life down. See if there's a trail of amino acids, and do they get stronger in one direction? Either the universe makes them and spreads them or they get spread by something. Either way, in the direction of the amino acids there is a higher chance of life. They may be preserved in some places. In those places is the highest chance of finding markers from others, if they wanted to communicate with us.

We're not ready

We are not ready to discover extraterrestrial life. We still don't understand plants. They are aware of their surroundings, they have different senses to ours but they are still aware. This blows our minds.

Their roots and leaves touch, they are sensitive to touch, orientation, light, seasons, slope, moisture, and other things, they communicate by giving off chemicals, etc.