Sulfurous signs of life

Jun 30, 2011 By Charles Q. Choi
This chart explains how astronomers measure the signatures of chemicals in the atmospheres of planets that orbit other stars, called exoplanets. Credit: NASA/JPL-Caltech

Any sulfurous molecules that astronomers spot on alien worlds might be a way to reveal whether or not those distant planets host life, researchers suggest.

On Earth, microbes can live off the energy available in sulfurous molecules that volcanoes release, essentially "breathing" these compounds the way humans breathe oxygen. If a similar kind of metabolism evolved on an extrasolar planet, the sulfurous molecules detected in the atmosphere of that world might help reveal the presence of alien life, said researcher Renyu Hu, a doctoral student in planetary science at MIT.

To see what telltale signs any sulfur-dependent life might generate, Hu and his colleagues modeled Earth-sized planets in the of sun-like stars -- that is, areas where worlds could have liquid water on their surfaces. These simulated planets possessed nitrogen-based atmospheres like Earth but 1,000 times more sulfur.

Habitable zones for different star types. Our solar system is used for comparison.

Sulfur-dependent releases hydrogen sulfide as waste. The researchers found these microbes could increase hydrogen sulfide levels by nearly 10 times what they would be on a planet without such life.

From interstellar distances, it would be hard to distinguish hydrogen sulfide (H2S) from water (H2O) on the surfaces of exoplanets. However, the researchers calculate that extra atmospheric hydrogen sulfide would in turn cause more pure sulfur aerosols to form in the air, which astronomers could detect based on their distinctive spectra or fingerprint in the visible and .

"Hydrogen sulfide emissions from the surface would have a large impact on the of a planet," Hu said.

Still, no Earth-sized planets have been discovered yet in the habitable zones of sun-like stars. "Characterization of the atmospheres of has been confined to close-in planets so far," Hu said.

Volcanoes on Earth can release huge amounts of hydrogen sulfide and other types of gases into the atmosphere. Credit: USGS

Also, Hu cautioned that hydrogen sulfide is not a conclusive signature of life. "We need to test our assumptions thoroughly," he said. "It may be, for instance, that volcanism could produce tremendous amounts of that gas."

is not the only biosignature gas the researchers are investigating.

"We want to study as many as possible -- look at many, many gases in Earth's atmosphere and see if they can be biosignatures as well," Hu said.

Hu, with his colleagues Sara Seager and William Baines, detailed their findings May 26 at the American Astronomical Society meeting in Boston.

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User comments : 17

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Aliensarethere
1.7 / 5 (3) Jun 30, 2011
We need a bullet-proof way of telling if there is life on a planet. It's not enough to say that it's probably created by life, just look at the Mars meteorite.
Johannes414
Jun 30, 2011
This comment has been removed by a moderator.
Darkwen
5 / 5 (1) Jun 30, 2011
moving right along....
MIBO
4.6 / 5 (11) Jun 30, 2011
maybe Johannes414 should stop to wonder who created God if it couldn't have evolved.

Ah, Stupid, I forgot. MAN created God as a way to control simple people.
Johannes414
1.3 / 5 (17) Jun 30, 2011
Hi MIBO,

Do you consider scientists like sir Isaac Newton and Blaise Pascal, both of whom were believers in God, to be simple people controlled by clergy? Newton for instance wrote more about scripture than on any other topic. Would you consider your own scientific achievements greater than his?
SemiNerd
4.6 / 5 (9) Jun 30, 2011
Hi MIBO,

Do you consider scientists like sir Isaac Newton and Blaise Pascal, both of whom were believers in God, to be simple people controlled by clergy? Newton for instance wrote more about scripture than on any other topic. Would you consider your own scientific achievements greater than his?

So? No matter what you say, If life couldn't evolve from nothing, neither could God. Unless we are back to the old 'it's turtles all the way down' fallacy. So where did God come from?
PieRSquare
4.5 / 5 (11) Jun 30, 2011
Knock it off with the God talk, it's against the commenting guidelines.
Johannes414
Jun 30, 2011
This comment has been removed by a moderator.
Johannes414
1 / 5 (11) Jun 30, 2011
Hi PieRsquare,

Hmmm. "Stop hiding those Jews, it's against the Neuremberg laws"...

No seriously, I guess you are sincere. But people can be sincerely wrong you know. I will never stop speaking about my and your Creator, and neither would you if you knew Him. It is a great joy to know the Lord. Be blessed.
GooglyMoogly
5 / 5 (6) Jun 30, 2011
Life is created by God. Life does not originate by itsself from dead matter, which is a biological impossibility. Ever seen some new life crawling out of your local pond?


Hello Johonnes,

Curious about the relevance of your comment. The article does not say anything about life springing forth from dead matter.

On Earth, microbes can live off the energy available in sulfurous molecules that volcanoes release, essentially "breathing" these compounds the way humans breathe oxygen. If a similar kind of metabolism evolved on an extrasolar planet, the sulfurous molecules detected in the atmosphere of that world might help reveal the presence of alien life...


Besides, we find "new life" all the time in all sorts of places on Earth. Well, new to humans anyways. Why not new life on other planets?
IlliterateGraduate
5 / 5 (1) Jun 30, 2011
This is a cool idea, but there are far too many possibilities that might result in the creation of these compounds. The only way we are going to know for sure is by observing it, or it observing us.... which I doubt microbes can do.... err

As for the whole God thing. Newton and Pascal are a little dated, and are really quite irrelevant when looking at the complex scientific issues of today. 300 years is a pretty long time, especially when you take into account how quickly thing have advanced in the last 50, or even 10 years.
Deesky
5 / 5 (3) Jul 01, 2011
We need a bullet-proof way of telling if there is life on a planet. It's not enough to say that it's probably created by life, just look at the Mars meteorite.

Only problem with that is that there is no bullet proof way of making that determination.

Even if Earth was viewed from lightyears away, there would be no conclusive chemical signature of life. Sure, you could probably detect high oxygen levels and carbon combustion byproducts, but is it bullet proof? No. It is however suggestive, which is the best you can do without actually going there or sending a probe.
kevinrtrs
1 / 5 (9) Jul 01, 2011
Hi GooglyMoodgly:
Curious about the relevance of your comment. The article does not say anything about life springing forth from dead matter.

But the whole unstated assumption behind the article is that there is NO creator and by implication therefore, life had to have arisen spontaneously from dead matter.
Sure it would be interesting to find life on some other planet because it would be a very stupendous find with all kinds of theological and scientific implications. But it still wouldn't explain how life arose in the first place. In fact it would create an even bigger mystery as to where life comes from.
Eoprime
5 / 5 (5) Jul 01, 2011
Hi GooglyMoodgly:
Curious about the relevance of your comment. The article does not say anything about life springing forth from dead matter.

But the whole unstated assumption behind the article is that there is NO creator and by implication therefore, life had to have arisen spontaneously from dead matter.
blablabla


So what?

You can always say God did it,
You could even say God touched those aminoacids some bil years ago (except that it would go against your rid. 6k Earth view)

No prove or disprove possible -> no science

So PLEASE do it somewhere else and take Johannes with you.
You are both really annoying and it seems reporting all those 'God did it, realize it you scumbags' comments dont help either.

On the Subject:
It would be nice if we could find a eath-sized planet in the habitable-zone in the first place. Is it possible to find some with current technology or do we have to wait for the next gen Equipment?
Resonance
not rated yet Jul 01, 2011
You realize your logic is flawed? I'm assuming both of you follow some particular religion. So, why have you chosen that particular faith? Human's all around the world have multiple different ways of interpreting God- what makes you think yours is the correct one? Seems like you were born into that frame of logic the same way a child suicide bomber believes in his cause.
Science is about determining reality through testable ideas.
In this light, evolution suggests that life can bloom anywhere in the Universe if the conditions are right.
The alternative and a more realistic interpretation of the Universe is: "God" is an idea of the trigger of the Big Bang which delivered all of the matter and energy in the Universe which could possibly lead to the development of life. In this context, "God" has already "touched" all of the matter, making it "alive". And there is simply no room for interaction with living or non living matter aside thru the natural physical laws.
UnlimitedRealms
not rated yet Jul 03, 2011
All the artical was about was how scientist were going to detect already exsisting life , not debate whether God had a hand in it or not .
I believe that scientists are going to have to look for a combination of atmospheric signs , not just one or two . If a sulfuric life form is the dominate life form then they will need to look for ALL the gasses that would influence an atmosphere in their proper proportions . Same for all other possible combinations of life and how they would infuence their enviroment as detected from our vantage point . Scientist will need many , many models to guide them by the time they find a potential habitable planet just so they may possibly know what they are looking for . To detect life from here is very complicated and can not be simplified in a couple of paragraphs .
danbal24
not rated yet Jul 04, 2011
After 20 years of studies about universe and everything that surrounds me, creation, big bang, redshifts, alien life form and a large etc the only conclusion i made is that no matter how hard u try to find out the supreme truth there is a point when everything becomes an illussion. I really think it´s not made to be known, at least not until we get ourself uplifted to another level of Consciousness.
Johannes414
1 / 5 (1) Jul 04, 2011
"Newton and Pascal are a little dated"

Really? Outdated? Like the laws of motion? Like the laws of ideal gasses? Like integral calculus?

These scientists are not outdated at all. Newtons mechanics helped the Apollo 13 land safely on earth. What is really outdated is the current obsession of science with itsself. Science is becoming a religion. Eventually, religious systems become corrupt.
FrankHerbert
1 / 5 (5) Jul 04, 2011
These scientists are not outdated at all.


No, but the societies that influenced their beliefs are.

Science is becoming a religion.


It's not, but I'll play along. Why is this a bad thing?

Eventually, religious systems become corrupt.


I couldn't agree more. I bet some even start out that way.

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