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Seth Shostak

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How to Find Extraterrestrial Life

Posted: 07/05/2012 10:02 am

It's largely a technical achievement, but it augurs well for the chances of finding life trillions of miles from Earth.

A team of mostly Dutch astronomers have used the Very Large Telescope -- situated atop a barren ridge in the Chilean Andes -- to examine a planet hugging the star Tau Bootis, 51 light-years away. The planet is hellishly hot and impressively hefty; it packs the mass of a half-dozen Jupiters. But the truly interesting thing is that the VLT was able to detect this world's elusive infrared glow. Applying a bit of spectral analysis, the team uncovered carbon monoxide in its atmosphere.

Now carbon monoxide, familiar to many as a noxious tail pipe emission, is just another of the simple molecules that are as common as clover in the cosmos. No biggie. But could this same technique be used to find biologically relevant gases, such as ozone (a form of oxygen) or methane? If so, it would be a method for discovering life from afar.

Frankly, today's telescopes would have a hard time pulling this off. But new, outsized instruments sporting mirror diameters of 100 feet or more are in the offing. They're complex and they're costly, but they're also game changers, and could offer a life-detection scheme as promising as sending people or probes to Mars.

Which brings me back to the summer of 2006, when I was preparing a talk about the search for extraterrestrial life for a group near San Francisco. The newspapers were thick with stories relevant to biology beyond Earth: ice on Mars, discovery of a few more planets, etc. If you paid attention to it all, you'd be swamped. But it struck me that by stepping back from this daily dose of astronomical revelation, it was clear that all these stories neatly fell into three categories -- three approaches to determining if there's anything alive out there.

In other words, there's a three-way horse race to discover extraterrestrial life. For your consideration and contemplation, I list this trio of trotters below:

1. Discover life nearby. This is horse number one, and where you'll find the big effort and the big money. National space agencies back this nag by sending probes that might eventually ferret out microbes in the dark aquifers beneath Mars' sterile landscape, or in the hidden oceans of such moons as Europa, Callisto, Ganymede, Titan or Enceladus.

This is the search for life in our solar system, a holy grail ever since Galileo first swung a telescope towards the moon. But so far, no joy. Despite tantalizing suggestions of fossilized microbes in meteorites, puzzling and possibly biogenic methane gas in the martian atmosphere, and a long-standing controversy over the Viking lander experiments of nearly 40 years ago, there's still no Exhibit A that points unequivocally to biology in our own back yard.

Nonetheless, the search goes on, becoming ever more extensive and more sophisticated. It's like Prince Henry the Navigator, sending ship after ship into the South Atlantic, hoping to find a route to the East. He eventually succeeded, and maybe we will too.

2. Sniff it out. Horse number two is the strategy described at the start of this article. A decade ago, NASA had plans to build a space-based, infrared telescope called the Terrestrial Planet Finder. It could both image exoplanets as well as do the sort of spectral analysis that might detect atmospheric gases caused by biology. Alas, the TPF is presently in a state of "indefinite hold," which many researchers think is a euphemism for rigor mortis.

But the idea is good, and either something like the TPF will eventually fly, or the humongous telescopes currently on the drawing boards will use their cyclopean mirrors to search out life around other stars by sensing its exhaust gases.

3. Eavesdrop on ET. Otherwise known as SETI, this third horse is an effort to detect radio signals or laser flashes from technically savvy extraterrestrials. The down side? Life able to build transmitters or lasers is surely less widespread than the type of single-celled organisms that might be discovered by schemes 1 and 2. So SETI will have to search farther and wider to win this race. The up side? It could, in principle, succeed tomorrow.

Of course, some folks consider SETI a long shot. But it offers a big payoff if it noses across the finish line first: Namely, life (or at least intelligence) that could have something interesting to say.

So what are the chances that any of these horses will make it into the stretch?

That's a big guess of course, and not much more than a guess. But unless you think that life is highly improbable -- that in a galaxy filled with planets and the basic molecules of biology, life only seldom appears -- then it's hard to believe that all three of these horses will scratch.

As to who's favored to prance into the winner's circle, my opinion is that, a priori, each of the contenders boasts roughly equal odds. In the next two decades, we'll see yet more robotic explorers on Mars, and possibly even on the more seductive satellites of the outer solar system. That's good news for horse one. But within the same time frame, large telescopes and possibly a cousin to the Terrestrial Planet Finder will be analyzing the light from planets around nearby stars. And SETI experiments -- assuming that continued funding can be found -- will increase the number of stellar systems examined by a factor of a thousand.

So the next time you check out the myriad science stories here and elsewhere that pertain to the matter of life beyond Earth, consider this simple way to categorize their relevance. The field is small, the contenders well-matched, and the horses are out of the gate.

 
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08:17 AM on 08/21/2012
http://www.endphysics.com/aliens_in_the_quran.html

"The idea that there is life elsewhere in the universe also, was derived from Mohammad when he told Muslims, "When you say: "Peace be upon us, you actually send peace on all the righteous people living on the Earth and in the heavens."This clearly implies that all type of people, live in the other worlds as on Earth. Also according to Imam Muhammad Ghazali 11th Century: "People in some of these planetary worlds have learnt to travel and communicate with each other.

Ibn-e-Abbas a Companion of the Mohammad became a great scholars. Maududi writing in his Tafhim-ul-Quran, says: "Ibn-e-Abbas believed with confidence that there are many more earth-like bodies in the heavens. He thought that such earths are inhabited by intelligent beings that their people are like the inhabitants on Earth. He even said that they may have a Prophet like Muhammad, a Adam like our Adam, a Noah, like our Noah, an Ibrahim like our Ibrahim, and a Jesus like our Jesus (pbuh)." (74) The knowledge of the existence of aliens and that they are mentioned in the Quran, has been present among Muslims from the earliest days of Islam!
07:49 PM on 07/11/2012
do we REALLY want a homing beam sent out to attract "intelligent" aliens ???
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Vik Dhawan
10:10 PM on 07/11/2012
We have been sending radio signal's for a long time.
02:54 PM on 07/12/2012
consider the time it would take for an alien race to receive, interpret, decide to invade, build a fleet, and then come here, why not?
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SocratesSiddhartha
"Poverty is the worst form of violence." Gandhi
06:12 PM on 07/09/2012
Be careful what you wish for...If you were to find an intelligent civilization capable of interstellar communication they just might not be too friendly.

Here on Earth we are the epitome of what we'd call intelligent and we are by far the deadliest animal known, the apex of apex predators, there isn't an animal on Earth ( including ourselves) from microbes to Blue Whales that we haven't dissected, enslaved, killed etc...

There's always a bigger fish eh...
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QuietProfessional
Recovering Jedi
11:07 AM on 07/09/2012
It's interesting that physical scientists seem to dominate the SETI field. But for a few self-styled "exobiologists", they're all astronomers or astrophysicists. And they're typically far, far more optimistics about the odds of finding extraterrestrial biological life than almost any biologist is! Is that because biologists have a real appreciation for just how extraordinary -- and, indeed, mathematically improbable -- life really is? Even here on earth?

That's not an argument against SETI. Just an observation. Maybe more biologists should be involved in SETI.

Of course, it's absurd for me to be commenting at all given that, as a conservative, I -- by definition -- do not "believe" in science.
11:57 PM on 07/09/2012
Correction: you believe in science as a market-based solution.
04:30 PM on 07/10/2012
Biologists are people who are investigating biological objects. SETI is looking for a radio signal. How would a biologist be helpful with that?
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QuietProfessional
Recovering Jedi
04:43 PM on 07/10/2012
I get your point. Although SETI also looks for signals generated by ET robotic entities, the dream is to make contact with EBEs. Knowing how to detect their biosignatures might help narrow the search. Otherwise, we're shooting in the dark.
08:19 PM on 07/08/2012
However we find extraterrestrial life, I just can't wait and hope we find it in my lifetime. I also want the "Earth is on 6000 years old" crowd to be silenced so that the United States can again become the science leader it used to be, and further, so allow science all over the world to accelerate the explosive advancements and discoveries it is making now.
IWantTofu
Evolution. Now a political position.
11:38 PM on 07/08/2012
For the "Earth is about 6,000 years old" crowd, what are the stars, and why do they shine at night?
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QuietProfessional
Recovering Jedi
11:08 AM on 07/09/2012
Actually, they shine all the time. Their light just gets "washed out" by the sun during the day. Although some supernova have been visible during the day.
01:44 PM on 07/09/2012
Exactly. It says in Genesis that God created the heavens and the earth, and that God placed the stars in the heavens to have the light from heaven shine upon the earth. It doesn't go beyond that, and apparently, evangelists never think beyond that. Sad, because they are missing the great bulk of creation itself.
10:18 PM on 07/07/2012
The U.S., the Chinese, Japanese and Indians are paying to build a telescope in Hawaii that would be almost 100 feet in diameter.......

Naturally, the Europeans want to outdo us by building their own which would have a hundred and 30 or 40 inch mirror............

They outdid us on Particle Accelerators too..........,

The U.S. used to lead the way in cutting edge technology..........,
06:54 PM on 07/07/2012
Dr. Shostak,

You stated the following:

“I can imagine that, within the Milky Way Galaxy, the number of contemporary intelligent civilizations, I think is probably in the thousands, maybe hundreds of thousands. But, the bottom line, actually, when people ask, Well, why do you think that they're out there? is that the universe is extraordinarily rich, extraordinarily vast. The number of stars that we can see is on the order of ten billion, billion star systems. So, unless there's something very, very special, miraculous, if you will, about our solar system, about our planet Earth; unless there's something extraordinarily unusual about it, then, what happened here must have happened many times in the history of the universe.”

[2004 DVD. The Privileged Planet: THE SEARCH FOR PURPOSE IN THE UNIVERSE. La Habra, CA: Illustra Media, 9 min.]

If my perception is correct, you were making reference to abiogenesis. One of the more famous chemists involved in the so-called origin of life experiments would seem to have had his original enthusiasm dampered:

“The problem of the origin of life has turned out to be much more difficult than I, and most other people envisioned.”

[Prof. Stanley L. Miller. 1991. In the Beginning... An interview by staff writer John Horgan. SCIENTIFIC AMERICAN, January, p. 117]
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Gas-Bag
There's nothing endearing about perfection.
09:38 PM on 07/07/2012
Baking a cake for the first time is difficult as well, particularly when there isn't a cookbook handy. In spite of that, once upon a time, through much trial and error someone did 'create' that recipe and by golly it tastes great.
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sLUCIDITy
No Deity Is My Shepherd For I Am Not A Sheep
02:28 AM on 07/09/2012
As usual, creationists and f@iry beleivers use outdated information. We have come leaps and bounds in the last 2 decades. We are tantalisingly close to creating life now.
01:46 AM on 07/07/2012
Did they call, yet?
And why isn't there even music on hold when you call them?

:-)
nschomer
Scientifically Progressive Libertarian Socialist
10:39 AM on 07/06/2012
Personally, my money is on #1. A large telescope array, or a good sized space-based one specifically sent to look at exoplanets might find some interesting spectral arrays, but that will never be accepted as sufficient evidence of life by itself. Case in point: we have already had readings of methane coming from the atmosphere on Mars, and interesting atmospheric readings from Titan, but you don't see respectable scientists claiming that this is enough to establish that there is life on either. And I find the conditions under which a civilization would be detectable by #3 to be so limiting as to be extremely unlikely, even given a large amount of targets. A civilization would have to be broadcasting a signal that not only could be picked up by other races searching for it, but also recognizable as such - if exponential growth in power usage continues, eventually a civilization would have the energy outputs of galaxies at their disposals, perhaps the pulsars that we detect ARE a type of Morse code, and specifically placed so as to be warnings/invitations/greetings/informative, but we simply have not decoded their significance. I think a single-source radio emission is rather unlikely, though.
08:18 AM on 07/06/2012
First of all, I can't remember where I read/heard this, and I really wish I could cite the speaker or author, but the fact is, if intelligent civilizations follow similar technological paths to what humans have followed, there is a very narrow window in which it is feasible to detect radio signals from other worlds. This is because the more technology advances (ie. the shift to digital/internet/cable/fiber-optics etc...), the quieter (more efficient) a planets communications become, the less noise is spilled out into space and the less the chances of us intercepting a signal. Even at its loudest though, it could be argued that at interstellar distances, only a beacon intentionally pointing at another star for the express purpose of making contact could possibly be powerful enough to be overheard....and even then, only if the civilization is looking for it. Pretty small odds.

Further, it could be argued that we do not want to make contact. If there were civilization out there actually capable of traveling interstellar distances (far superior to us), what would happen if they made it to Earth, proceeded to colonize it and we tried to disallow them from doing so. Just think about what we did to the indigenous cultures in North America when we got here. We'd be swatted like flies.

As thrilling as it would be to eavesdrop on interstellar signals, I'm not sure I'd want to make "Contact".
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phal4875
The world is run by cats; we just feed them.
08:15 PM on 07/06/2012
Fanned for a well thought out post.
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QuietProfessional
Recovering Jedi
11:14 AM on 07/09/2012
That's a good point--I've read the same thing. When a civilization goes digital, it also goes quiet. Spread spectrum transmission -- now the norm even for wi-fi networks in the home -- sound like white noise if you don't have the right equipmet. And they transmit at extremely low power.

A spacefaring civilization would be wise to maintain a low profile, not knowing what's out there.

Blasting a radio transmission into outer space, for the express purpose of arousing an extraterrestrial response, is like running into the jungle at night, blind and naked and shouting "I'm here!" Only a fool or madman would do that.

Better to conduct a quiet reconnaissance first.
03:01 PM on 07/15/2012
LMAO! Great analogy.
12:44 AM on 07/06/2012
How to find extraterrestrial life? How about using scientific methods rather than the religious belief that is uses 1950s radio technology and Morse code?

:-)
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QuietProfessional
Recovering Jedi
11:16 AM on 07/09/2012
That's just silly. Elvis already told me that ET's are real.
06:11 PM on 07/05/2012
Some are already here visiting us and there's a paper trail that the American government is covering it up: James Fox's "Out Of The Blue" http://youtu.be/cYPCKIL7oVw
Other governments acknowledge their presence, but defer to U.S. the world superpower for full disclosure: "Mexican Govt Admits aliens are real" http://youtu.be/hKdvBidbwnQ
Mr. Shostak personally told me this is "nonsense"...and that is the mentality leading our search for extraterrestrial life. Disheartening
James Fox's "I Know What I Saw" http://youtu.be/Mia70txRLXc
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sLUCIDITy
No Deity Is My Shepherd For I Am Not A Sheep
02:38 AM on 07/09/2012
Sorry AstronoVerse, as much as I wish it were true, the stories you cite are riddled with inconsistencies and unverifiable information. You need to learn how to sceptically assess conspiracy theories so as to not fall for them.
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Overtone
See bio on the Aesop Institute website
03:53 PM on 07/05/2012
The late Dr. Robert Carroll was a mathematical physicist.

He developed a non-relativistic alternative physics.

Pion fusion is now under development by two groups.

Carroll believed pion fusion could propel a spacecraft to speeds approaching 20 million times the speed of light.

See Pages 26-26 of Cheap Green at www.aesopinstitute.org

If his alternative physics is one day proven correct, exploration of Goldilocks planets may actually be possible.
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Overtone
See bio on the Aesop Institute website
03:59 PM on 07/05/2012
That should read see pages 26-29. Sorry for the typo.
12:47 AM on 07/06/2012
OK, let me put it this way... the existence of "goldilocks" planets depends in no way on the writings of, yet another, pseudoscience prophet.
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Overtone
See bio on the Aesop Institute website
02:17 AM on 07/06/2012
Goldilocks planets have been predicted for several decades and are now apparently surfacing. Substantial numbers are postulated by reasonable math.

Dr. Carroll devoted his life to mathematical physics. His last paper was delivered at the AAAS meeting in San Francisco in 1994. He concluded that presentation based on non-relativistic physics by writing on the blackboard that the maximum speed of a spacecraft would be 20 million times the speed of light.

Several of his other predictions have now turned out to be correct.
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JoeyDee2
I know what just passed here
02:53 PM on 07/05/2012
They're certainly not going to come here looking for us.
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MacTheCat
Those Clouds You See Aren't really clouds at all
01:04 PM on 07/05/2012
How to Find Extraterrestrial Life

At the Republican Convention?
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QuietProfessional
Recovering Jedi
11:19 AM on 07/09/2012
I'll bet you think you were the very first person on HuffPo to come up with that one, don't you?

Besides which, many presume that ETs would likely be far wiser and more evolved than humans.

As a Republican, I say: All your base are belong to us!
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MacTheCat
Those Clouds You See Aren't really clouds at all
03:09 PM on 07/09/2012
Alright...you made by chuckle!