From the University of Toronto:
Search for life on exoplanets more difficult than thought
A new study from the University of Toronto Scarborough suggests the search for life on planets outside our solar system may be more difficult than previously thought.
The study, authored by a team of international researchers led by UTSC Assistant Professor Hanno Rein from the Department of Physical and Environmental Science, finds the method used to detect biosignatures on such planets, known as exoplanets, can produce a false positive result.
The presence of multiple chemicals such as methane and oxygen in an exoplanet’s atmosphere is considered an example of a biosignature, or evidence of past or present life. Rein’s team discovered that a lifeless planet with a lifeless moon can mimic the same results as a planet with a biosignature.
“You wouldn’t be able to distinguish between them because they are so far away that you would see both in one spectrum,” says Rein.
The resolution needed to properly identify a genuine biosignature from a false positive would be impossible to obtain even with telescopes available in the foreseeable future, says Rein.
“A telescope would need to be unrealistically large, something one hundred metres in size and it would have to be built in space,” he says. “This telescope does not exist, and there are no plans to build one any time soon.”
Current methods can estimate the size and temperature of an exoplanet planet in order to determine whether liquid water could exist on the planet’s surface, believed to be one of the criteria for a planet hosting the right conditions for life.
While many researchers use modeling to imagine the atmosphere of these planets, they still aren’t able to make conclusive observations, says Rein. “We can’t get an idea of what the atmosphere is actually like, not with the methods we have at our disposal.”
There are 1,774 confirmed exoplanets known to exist, but there could be more than 100 billion planets in the Milky Way Galaxy alone. Despite the results, Rein is optimistic the search for life on planets outside our own is possible if done the right way.
“We should make sure we are looking at the right objects,” he says, adding that the search for life within our solar system should remain a priority. He points to the recent discovery of a liquid ocean on Enceladus, one of Saturn’s larger moons, as a prime example.
“As for exoplanets we want to broaden the search and study planets around stars that are cooler and fainter than our own Sun. One example is the recently discovered planet Kepler-186f, which is orbiting an M-dwarf star,” says Rein.
Rein says locating a planet in a habitable zone while being able to obtain a good resolution to model the atmosphere will help determine what’s on the planet.
“There are plenty of reasons to be optimistic that we will find hints of extraterrestrial life within the next few decades, just maybe not on an Earth-like planet around a Sun-like star.”
http://www.pnas.org/content/early/2014/04/23/1401816111
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I think it’s simpler than that: ET is hiding in the deep ocean.
Looking at the logical argument for life “out there,” the logic always was the same. We knew long ago that there is at least one stellar system with planets. That meant that the probabilty of stars with planets was 1.0. The only question was how it applied outside the solar system. Recent data now indicates that the probability of extrasolar planets is 1.0 as well and the real question is how likely stars are to have a planetary system and the present progress show that the only viable descriptor is “very.”
The same is true for the probability of life. It is 1.0. Again we don’t presently have an adequate sample to discuss other stars, but the prior probability is that given even one living system there are likely to be other living systems. The real question comes down to how can we recognize life? Is the life on earth typical or unusual as living systems go? Life – as WE know it – creates unique signatures including an apparently chemically unstable atmosphere, but prior to the appearance of photosynthetic organisms archaea were happily fermenting their way toward civilization employing a broad variety of strategies to extract energy from the environment that did not include oxygen. The level of oxygen in the atmosphere was immensely lower and the atmosphere itself a chemically reducing rather than oxidizing atmosphere. So, we know that life that yields an oxidizing atmosphere is not historically the only game in town, even on this planet. In short, it is not clear that we would necessarily be able to recognize indications of life. When you look at Fermi’s paradox it seem far less paradoxical if you assume life is common but neighbors incapable of minding their own business are rare.
“””””…..Duster says:
April 30, 2014 at 11:48 am
george e. smith says:
April 29, 2014 at 4:42 pm
…
So far as I know, life on earth began some 4.5 billion years ago, and I’ve seen no evidence of it ever beginning again anywhere in the universe, including on earth.
Somewhat later probably. The planet itself is only about 4.5 BY old as best geology can estimate. As regards evidence of extraterrestrial life, that relies largely on what we consider “evidence.” There are reasonable grounds for arguing that Viking may well have detected life of some form on Mars in one test, while the other tests that accompanied the Viking lander might well have yielded false negatives. …..”””””
So I’m not a Gee-ologist; so I picked a number. I don’t think the point I made, changes one iota, if the number is between one and ten billion, so I went for a near middle ground.
I’m happy to use ANYBODY’S other number. I notice; you do not have a number.
And a lot of if ands or buts, in your “evidence”..
I’ve personally seen the most amazing structures appear, as if by magic, from presumably quite inanimate materials.; right before my eyes.
In one case, from getting HCl on the edge of an ordinary piece of 1100 alloy Aluminum; and of course there’s the ice forming on glass window panes..
But my assertion was “””””…..So far as I know, life on earth began some 4.5 billion years ago, and I’ve seen no evidence of it ever beginning again anywhere in the universe, including on earth……””””
So for 4.5, read “x”. The rest is true.
“””…There are “reasonable grounds” for “arguing” that Viking “may well have”…. etc etc. A really definitive statement to be sure.
I’m quite happy to accept expert assertions, if and when they do find “it” or “et” along with “credible evidence” that it was not transported to the discovery site from earth; just as Mars meteorites, have supposedly arrived on earth. I’d be happy as a clam, actually.
george e. smith says:
April 30, 2014 at 12:22 pm
How I’d state the present case is that evidence supportive of ET life exists, but it’s so far not conclusive. Alternative explanations exist for the supportive observations, just as there are problems with some of the evidence arguing against life on other bodies in the solar system.
NASA asks for your help in designing a low-cost, signs of life-seeking mission to Europa:
http://www.space.com/25672-jupiter-moon-europa-nasa-mission-ideas.html
milodonharlani says:
April 30, 2014 at 12:03 pm
…
Methane, contrary to common discussions, is not and should not be treated as an indicator of life off earth. It has baffled me for years that NASA talks about it as if it meant something more than that carbohydrates were present that might support terrestrial life. The compound is wide spread even within the solar system in abiotic situations (look at the outer planets and moons for instance) and it’s signature occurs in interstellar space. Mar’s chemistry is quite different – self evident I know – but the search for methane assumes earth-like chemistry. Even on earth there living communities that would fail the test; look at extremophiles.
My sole point is that rather than “no evidence,” we have equivocal indications, and that equivocacy is attributable to our state of knowledge or lack there of. See here for example:
http://www.ncbi.nlm.nih.gov/pubmed/10235261
We do not actually have a universally functional definition of life. Our ability to recognize life is condition by the planet, which has had a biosphere so long that much of what we expect is already conditioned by the presence of life.
Duster says:
April 30, 2014 at 12:39 pm
Of course methane by itself doesn’t confirm life, since it also is produced chemically, but the concentrations of it allegedly detected in Martian air previously suggested replenishment biologically.
As I noted, your main points are valid. Life not like terrestrial forms has as you know been hypothesized for Saturn’s big, hydrocarbon rich moon Titan, with liquid ethane & methane as its basis instead of water. These hypothetical organisms would inhale H2 in place of O2, metabolize the hydrogen gas with acetylene instead of glucose, & exhale methane instead of CO2.
inre: george e smith
Goldilocks and her zones get a little assistance from quantum info sharing from other multiverses when she needs to assemble DNA, the last I heard.
As for Duster’s “statistical existence” theories, that’s like playing the lottery.
If you buy a ticket and you win; you think the probability of winning is 1.0. But the millions of other people who did exactly the same thing; bought a ticket, they all lost, so they say the probability of winning is 0.0.
Pretty much the same with stars; isn’t it. ?? Sol won with just 8 tickets. Proxima Centauri, is currently a loser.
I don’t know if you are old enough to remember the very first “Draft Lottery”, held during the Viet Nam War.
18 year olds were registered by their calendar birth date; on of 366 possible dates each year.
Numbers were drawn, corresponding to those dates in order; or the equivalent of that. People with early drawn numbers were drafted; absent some out dispensation.
Within days of the results being posted; some university mathematician declared the result unfair, and discriminatory towards people born early in the year.
The exact sequence of dates drawn, was one out of 366! possible results; a near infinite number, to ordinary folks.
An equally likely result would have been if the dates came up in calendar order ; Jan 1, Jan 2, Jan 3, ……Dec 29, Dec 30, Dec 31.
Yet this brainiac declared the result non-random, on the basis of one event out of 366 ! equally possible events. That number is about 9.186 x 10^780.
That’s a 9 followed by 780 zeros. I don’t think there are that many everythings, in the entire universe !
But the guy said just the first of many was biased..
So yes if you buy a ticket, you can win. If you don’t, you can’t.
We won !
george e. smith says:
…
April 30, 2014 at 12:22 pm I’m quite happy to accept expert assertions, if and when they do find “it” or “et” along with “credible evidence” that it was not transported to the discovery site from earth; just as Mars meteorites, have supposedly arrived on earth. I’d be happy as a clam, actually.
As far as numbers go, tossing them around sounds like we know more than we do. If the planet is that old, and you say life has been around since that time, you pose the possibility that life is intrinsic in the process of planetary formation – and wouldn’t that be something, which I do not think you want to do. The fact that those spontaneous, orderly patterns you describe appear at all, might be why life exists. Ira Prigogine suggested as much decades ago discussing non-equilibrium systems. His argument is still reasonable.
As far as the the above quote is concerned, just how will we recognize “life.” As it is, the earliest evidence of life is already so early it is practically embarrassing. The environmental conditions then would kill most if not all modern life forms. Which is again is the point. What conditions define the presence of life? Would the Viking tests have successfully have detected it?
The Mars results are equivocal, not definitive. They neither prove nor disprove anything except that our imagination has limits. Right now, as you say, they don’t support the hypothesis, but that is a statistical argument at its root – balancing the risks of being wrong vs being right. As I said, right now your approach is the best. It is secptical, which is a good thing in general. But, once we start sending sample homes, that single “positive” looms far larger. The Viking “positive” result shows the presence of some process that fixed a radioactive trace into as gas molecule. The argument made by the lead was that the process was a living one. The remaining tests depended much more on assumptions about what life was based upon terrestrial life. They disproved the presence of anything like a modern earth-like biology. So again, “no life as we know it.” But we can’t safely say “no life.”
Don’t worry, they will. Or rather we, mankind, will. Assuming that the Neo-Luddites and Islamofascists, and all the other enemies of progress and civilization don’t first send us back to the Stone Age (not the Iron Age—the Luddites won’t let us despoil Mother Earth by digging up ore, you know).
Will we have invented a Warp Drive by the 24th century? I don’t know, but we’ll have figured out some way of getting to the stars. We can always freeze folks for long journeys and thaw them out when they arrive. But I hope we’ll find a way around c.
When I was young and reading Willy Ley and Chesley Bonestell’s The Conquest of Space (which I still have), I fully expected by now that we’d have gotten to Proxima Centauri, if not farther. It’s a real disappointment that we’re still fretting about getting even to Mars.
It is a real accomplishment that we have managed to detect extrasolar planets orbiting other stars. This is brand new, so it’s not surprising that we can’t yet tell much about their composition. It will be a while, maybe a long while, before we can identify any signs of life—who expected otherwise? The exercise of exploring the moons of the giant planets will help in refining our criteria. But exobiology is a very young field. As it develops, I am quite sure it will shed light on the basic question: how did life originate on Earth?
Good comments from Duster and milodonharlani, proving there is “intelligent life down here.”
/Mr Lynn
I always liked that old grafitti: “Is there intelligent life on earth?”
underneath: “Yes, but I’m just passing through.”
ferd berple says: April 30, 2014 at 6:21 am
the bigger question is how did God start from non God? what was the process that created God?\———————————————————————
There is THAT which was not born, nor created, nor evolved. If it were not so, there would never be any refuge from being born, or created, or evolving. THAT is the end of suffering,….THAT is God**
** You may substitute your preferred label..Tao, Brahman, Cosmos, Allah, Nirvana, Non-duality, Being, Etc..
Duster says:
April 30, 2014 at 1:10 pm
Even on earth there is no consensus as to a strict definition of life. There is maybe, sorta general agreement that viruses might be alive but prions probably not, yet you’ll still find those who disagree as to both forms, yea & nay. Does life have to exhibit both metabolism & replication, or does the latter suffice? There remains a grey area between living & not living.
You have to wonder if there is not some elemental principle, a ‘life force’, that we have not identified. It is an old concept. From one of my favorite stories,
The rest here: http://gaslight.mtroyal.ca/derelict.htm
Perhaps the principle lies with an inevitable tendency in the Universe toward increasing complexity, given inputs of energy and ‘material’, with life being a consequence of that process. In which case, we should expect life elsewhere in the Universe, and plenty of it. As for why we haven’t been noticed yet. . . Do you pay much attention to the colonies of tiny shrimp under the dock down by the harbor?
/Mr Lynn
Maybe the astronomers searching for ET could get more government funding if they said their search was made more difficult by climate change.
Not to mention viroids &, more to Duster’s point, nanobes:
http://serc.carleton.edu/microbelife/topics/nanobes/index.html
Mr Lynn says:
April 30, 2014 at 2:52 pm
The tendency of the universe is toward entropy, against which current life swims.
Ralph Kramden says:
April 30, 2014 at 2:56 pm
If clouds increase due to a return to Maunder Minimum climatic conditions, maybe taxpayers will foot the bill for more space telescopes.
george e. smith – you say my “100,000 year round trip example, is way overkill.“.
Our galaxy, I am told, is about 100,000 light years across. I took half that, giving a 100,000 year round trip. Maybe 50-60,000 years would have been more reasonable. With the thickness of the galaxy being some 3,000 light years, the likelihood of that planet being only 50 light years away is tiny. Yet you are quite right, even 100 years is a very long time in Earthling memory terms.
So it is said, though how we can generalize about the entire universe, whose ultimate scale and properties are unknown, I don’t know. But setting that imponderable aside, we have billions of huge powerhouses called stars pouring vast quantities of energy (heat, light, electromagnetic, particle) upon every piece of flotsam and jetsam in their neighborhoods. We know that in these furnaces basic elements like hydrogen and helium are converted to more complex ones, like carbon (increasing in complexity). We also know that in primordial environments this flood of energy can produce reactions and combinations that lead to complex molecules like amino acids, even in space. So at least within local environments we have nature working against entropy. There is still a huge jump to what we would recognize as ‘life’, but it is conceivable to me that, given sources of energy, the tendency of matter is toward increasing complexity, not the reverse.
If this speculation were so, then we might ask: Is the “current life” (as you put it) the end result of this process? Or are there higher levels of complexity possible, which might make our highly-organized look as primitive as amoeba do to us?
/Mr Lynn
That’s “highly-organized bodies” in the last sentence. /Mr L
Mr Lynn says:
April 30, 2014 at 4:26 pm
The Second Law is an empirically validated postulate of thermodynamics, & as such appears to operate throughout the observable universe. It states that the entropy of an isolated system never decreases, because isolated systems always evolve toward thermodynamic equilibrium, a state with maximum entropy. Maybe the universe isn’t an isolated system, but in that case, then it’s part of a multiverse, & all bets are off.
The “current” of which I speak is the tendency towards entropy, not toward a vital principle behind life. All large & small scale organization like galaxies, suns, microbes & atoms tend to decay following the arrow of time. There can be local, temporary exceptions to the 2nd Law, but in the end the rules of this universe win.
It has been known for almost two centuries now that there is no vital energy unique to life, the chemistry of which is no different from that which occurs in reactions outside of living things.
Just to be clear, “current” was a metaphor based on the difficulty of swimming upstream against the flow of a river. In this case, that means that life has a hard time overcoming the entropy of the universe & is doomed ultimately to lose, being swept out to nothingness.
Sorry. Missed that. Kind of a dismal vision, wouldn’t you say? Think instead of the little sperm cells, swimming upstream. . . And one of them is going to win!
/Mr Lynn
“””””…..Mike Jonas says:
April 30, 2014 at 3:55 pm
george e. smith – you say my “100,000 year round trip example, is way overkill.“…….””””””
Mike, I meant NO criticism of your example; merely pointing out, that human patience is much less tolerant of delay in “satisfaction”, when it comes to waiting for a response to our actions.
I doubt, that we would wait for an answer from Alpha Centauri.
I’m sure that much of the motivation to search for ET; especially intelligent ET, comes from persons, who think, that our many problems, could be solved for us by contact with a “more advanced” intelligence. I think that is a dangerous notion.
WE are responsible for ALL of our problems, and if WE are too damn stupid, to solve these issues; and I’m talking “behavioral” issues, then we have no real claim to “intelligence”, nor are we deserving of survival. Mother Nature will crush us like a snail, unless we get with the program; and in no way am I referring to “dealing with” some imagined climate catastrophe.
Believers say out of nothing was created everything. Science says out of nothing was created everything. Only the flow of events is argued. I could care less; we will probably never know. Only speculate, theorize, or take it on faith. My small brain focuses on small questions: What gene switched on to make the first Orb Weaver spider spin the first orb? Or, how did a cave swallow figure out that it could build a nest out of spit? I leave M theory, bubble universes and 11 dimensions to others.
Thinking we are the best and only creation our universe can produce is pure narcissism, arrogance, or zealotry. We are not advanced enough to prove or disprove that this planet is nothing more than a Petri dish. However, we do have a few billion years to learn…if we don’t kill ourselves, get hit by the big one, or fry when the global average temperature goes up another 0.1C.
Until then, I will use my too few remaining years contemplating the evolution of the cigar and how rotten barley became beer.