Possibility of Life in the Universe

[iquestor]

Going over the Kepler website, I found this quote in the article about the extension of Kepler's Mission back in April '12:

Another of Kepler's findings pertains to the reasonable assumption that the Sun would be typical of Sun-like stars. But it's not. Most other stars' data exhibit greater variations in brightness than the Sun—they're "noisier. As Kepler Principal Investigator, Bill Borucki, has said "we were surprised by the universe."

What implications does this have for LAWKI? Does a 'noisier' star have a negative impact on the chances for higher life, or lifer ever starting at all? If so, would this discovery have us looking for life around 'quieter' stars with planets ?

[swampyankee]

Going over the Kepler website, I found this quote in the article about the extension of Kepler's Mission back in April '12:




What implications does this have for LAWKI? Does a 'noisier' star have a negative impact on the chances for higher life, or lifer ever starting at all? If so, would this discovery have us looking for life around 'quieter' stars with planets ?

I think the only sensible answer at this time is "we don't know."

I suspect that the activity of stars varies with time, so it's possible that the Sun is in a relatively quiescent period. Main sequence stars, like the Sun, exhibit a long-term increase in brightness, from their development along the main sequence, and during this time, the amount of short-term variability may change. I remember reading that this may be the case with M-class stars, some of which exhibit extremely large flares, but others, which seem similar, do not. Since the flares for M-class stars produce large amounts of UV, they would probably sterilize a planet's surface, even if the planet had an oxygen atmosphere, as the normal level of UV would result in an optically thin ozone layer (see Segura et al "Ozone Concentrations and Ultraviolet Fluxes
on Earth-Like Planets Around Other Stars," http://www3.geosc.psu.edu/~jfk4/Pers...biology_03.pdf ).

[John Jaksich]

I think the only sensible answer at this time is "we don't know."

I suspect that the activity of stars varies with time, so it's possible that the Sun is in a relatively quiescent period. Main sequence stars, like the Sun, exhibit a long-term increase in brightness, from their development along the main sequence, and during this time, the amount of short-term variability may change. I remember reading that this may be the case with M-class stars, some of which exhibit extremely large flares, but others, which seem similar, do not. Since the flares for M-class stars produce large amounts of UV, they would probably sterilize a planet's surface, even if the planet had an oxygen atmosphere, as the normal level of UV would result in an optically thin ozone layer (see Segura et al "Ozone Concentrations and Ultraviolet Fluxes
on Earth-Like Planets Around Other Stars," http://www3.geosc.psu.edu/~jfk4/Pers...biology_03.pdf ).

Once again, we are arguing from an anthropocentric point of view--and I agree with the point -- "we don't really know" Life may evolve or may not possess that ability to adapt to the situation mentioned above in OP. It is intriguing to speculate to upon but it not should curb our own curiosity or desire to study these systems from far away . . . or eventually up close. It may prove useful to "us" if we can understand it better.

[swampyankee]

Once again, we are arguing from an anthropocentric point of view--and I agree with the point -- "we don't really know" Life may evolve or may not possess that ability to adapt to the situation mentioned above in OP. It is intriguing to speculate to upon but it not should curb our own curiosity or desire to study these systems from far away . . . or eventually up close. It may prove useful to "us" if we can understand it better.

I hate not knowing, so I would like for somebody to fix the "we don't know." We may be able to get indirect indicators of life as we know it, such as ozone lines from an extrasolar planet's atmosphere, but we won't really know without technology we do not currently possess, and may never possess.

[John Jaksich]

I hate not knowing, so I would like for somebody to fix the "we don't know." We may be able to get indirect indicators of life as we know it, such as ozone lines from an extrasolar planet's atmosphere, but we won't really know without technology we do not currently possess, and may never possess.

Did not want to come off trollish? but I certainly agree with you---I still hold out a little "hope" of eventual resolution. I am reminded of a certain aphorism used in business-speak:
"All advances in technology come from a break from current technology--or thinking out of the box, essentially"

or put another:

"Assuring that we leave a scientific legacy for future generations, allows the possibility of not being forgotten"

[iquestor]

Current advances in knowledge just seem to keep us guessing!

We now know small rocky planets in favorable orbits are not rare, which gives us hope of finding life, but is counterbalanced with the knowledge that we seem to have an unusually stable star.

We know there are billions of planets out there which orbit red giants and binary systems which extends where we think LAWKI could evolve (in light of recent discoveries of organisms thriving in extreme environments), but SETI Has turned up nothing.

The more we know, the more we realized we don't know so much.

[ravens_cry]

The universe is always full of surprises, especially when on the frontiers of the known like Kepler is.
What does this mean for life in the universe?
I think we are going to need a few more generations of space telescopes to tell.

[CARREEN]

I think there have life in Universe.One day we will able to find out them.Hope this time isn't so far, because our space technology developing rapidly.

[Gomar]

Current advances in knowledge just seem to keep us guessing!
but SETI Has turned up nothing.

Right, nothing! Why?
If aliens are thousands of years behind us in tech, or at about the same level, we wont hear from them
nor be visited. The only aliens capable of space travel must be millions of years ahead of humans.
So, would they use radio to send signals into space? No, it's laughable.
Thus, we know for a fact Earth has not been invaded nor colonized by alien forces. There are no
alien visitors vacationing in Hawaii, or Paris, or eating pizza in Brooklyn. We can deduce that no aliens are capable of doing so, and wont be doing so as nothing of the sort has happened in 300m years, and likely wont ever.

[Colin Robinson]

Current advances in knowledge just seem to keep us guessing!

We now know small rocky planets in favorable orbits are not rare, which gives us hope of finding life, but is counterbalanced with the knowledge that we seem to have an unusually stable star.

We know there are billions of planets out there which orbit red giants and binary systems which extends where we think LAWKI could evolve (in light of recent discoveries of organisms thriving in extreme environments), but SETI Has turned up nothing.

The more we know, the more we realized we don't know so much.

Radio SETI only has the potential to detect a small subset of the possible forms of life. To be detectable that way, they would need to be enough like us to be able to build radio transmitters, yet enough unlike us to disregard the risks of messaging to other stars.

So the fact that SETI has turned up nothing, doesn't really tell us very much.

One area where our knowledge has been increasing, is about the occurrence of organic molecules in the universe, both within and beyond this solar system. Which is relevant, because Life As We Know It is a system of organic molecules. If we really want to know more about life in the universe, and about how life in the universe relates to other stuff happening in the universe, why not focus on places where we know that organics are present, to find out how organic compounds behave in a range of conditions?

[iquestor]

I get what SETI currenty does and I know it is a small subset of conditions and advancements we are looking for; I don't think it is "laughable" to think we might intercept some radio message from an alien transmitter -- many people smarter than I, Like Carl Sagan, Jill Tartar, and Frank Drake spent a lot of time looking and listening. There are other ways of conducting SETI searches, I hope we come up with some other, more promising theories of how we could detect alien technology. I had read something to the effect that warp drives (such as an Alcubierre drive ) would possibly leave some tell tale traces that could be detected from very far away, but I don't remember the details.

As far as Organics, Maybe Curiosity will find something interesting in those dark bands near Glenelg !!!

[ravens_cry]

I think SETI is a good thing even if it won't detect nearly all intelligence.
I believe it it is possible it will find some, and if it finds any it will have done its job.

[Colin Robinson]

I get what SETI currenty does and I know it is a small subset of conditions and advancements we are looking for; I don't think it is "laughable" to think we might intercept some radio message from an alien transmitter -- many people smarter than I, Like Carl Sagan, Jill Tartar, and Frank Drake spent a lot of time looking and listening.

I don't think it's laughable either. Continuing, patient work on radio SETI may eventually bring a positive result, and if it does, that would be a huge breakthrough.

I do get concerned when someone like Paul Davies says stuff like:

"Suppose life is a freak phenomenon, the outcome of an incredibly unlikely chemical fluke, unique in the observable universe? Then we will indeed be alone. That view was the prevailing opinion when SETI began 50 years ago, and is still widely held by biologists."

http://www.amazon.com/The-Eerie-Sile.../dp/0547133243

I'm not convinced that this "fluke" theory of the origin of life is or ever was as "prevailing" or as "widely held" as Davies asserts. Nor do I think that the so-far negative results from radio SETI are much of an argument in favor of the "fluke" theory.

There are other ways of conducting SETI searches, I hope we come up with some other, more promising theories of how we could detect alien technology. I had read something to the effect that warp drives (such as an Alcubierre drive ) would possibly leave some tell tale traces that could be detected from very far away, but I don't remember the details.

All these possibilities are worth considering, I agree... But the title of this thread is "Possibility of Life..."

So maybe we should be thinking not just about SETI, but rather about the broader field of SETL -- Search for Extraterrestrial Life?

As far as Organics, Maybe Curiosity will find something interesting in those dark bands near Glenelg !!!

Maybe it will...

And let's not forget that Cassini-Huygens has already detected a great range of organic compounds (small and large, identified and unidentified) in Titan's atmosphere and on its surface.

[iquestor]

we really need another mission to Titan!!!

[Paul Wally]

I'm not convinced that this "fluke" theory of the origin of life is or ever was as "prevailing" or as "widely held" as Davies asserts. Nor do I think that the so-far negative results from radio SETI are much of an argument in favor of the "fluke" theory.

I have some doubts about the idea of life being just an unlikely fluke, but there is another possibility and that is that maybe we are one of the first civilizations.

On the other hand, if there are a very large number of civilizations out there capable of inter-stellar communications, then we have to consider the possibility that their signals are all around us and that we just need to invent the technology to detect them. So, in essence, the search for Extraterrestrial intelligence then becomes a search for new communication technologies.

[Colin Robinson]

I have some doubts about the idea of life being just an unlikely fluke, but there is another possibility and that is that maybe we are one of the first civilizations.

I'd agree that we may be "one of the first" in the sense that there is no other civilization within a few hundred light years.

On the other hand, I don't see much reason to think we are the first in the universe, or even the first in the Milky Way galaxy, to reach the level of complexity and adaptability we call civilization.

I know the argument that a civilization with space travel would expand and fill its galaxy in a few million years.

But this seems to me rather like saying that a civilization with digging equipment would within a few million years dig a burrow right through its own planet and come out again on the other side!

I'd agree, though, that very complex forms of life may be rare in comparison to simpler forms.

Even if there is a high probability of life appearing on a habitable world, and a high probability of intelligence evolving in a similar time span of billions of years as here... another factor to consider is the probability that a particular habitable world will remain habitable for those billions of years.

The opening post of this thread mentioned fluctuations in the luminosity of stars. This is one factor you'd have to consider in assessing the chances of a planet or moon not only being habitable, but remaining habitable over the long term.

Conceivably the nearest life may be as near as Europa or Titan, but the nearest intelligent life could still be thousands of light years away...

On the other hand, if there are a very large number of civilizations out there capable of inter-stellar communications, then we have to consider the possibility that their signals are all around us and that we just need to invent the technology to detect them. So, in essence, the search for Extraterrestrial intelligence then becomes a search for new communication technologies.

That's another possibility to consider, yes... But how would we conduct such a search?

[iquestor]

Well, I read "The Eerie Silence" by Paul Davies and he had many suggestions for the next searches:
1. conduct in-system searches for artifacts (sentinels) on the moon and asteroid belt
2. look in our DNA for messages
3. Look for large scale side effects of advanced technology like warp drives, dyson spheres, etc
4. look for messages imprinted on the CMB

I was kind of put off by his final remarks that, as a scientist, he feels we are utterly alone as the only intelligence in the galaxy.

[Colin Robinson]

we really need another mission to Titan!!!

Yes, I wholeheartedly agree.

Well, I read "The Eerie Silence" by Paul Davies and he had many suggestions for the next searches:
1. conduct in-system searches for artifacts (sentinels) on the moon and asteroid belt
2. look in our DNA for messages
3. Look for large scale side effects of advanced technology like warp drives, dyson spheres, etc
4. look for messages imprinted on the CMB

It seems to me that each of these strategies is like the current radio SETI project -- it asks a yes/no question, where a yes answer would tell us a lot, but a no answer would tell us very little.

What I think would be better, would be what you said in your earlier posting: another mission to Titan.

I think it should be designed to have a general look at the organic molecules there, and try to answer the question of how they are behaving.

Here a number of possible answers are imaginable -- it is not just a yes/no thing.

The organics may have formed systems we will recognize as living things; or they may be behaving in ways that clearly have nothing to do with life; or they may be behaving in ways which we will find hard to classify, either as living or non-living.

Any of these answers will add something significant to our knowledge of how organic chemistry works at the scale of a planet-sized body. Any of these answers is highly likely to add to our knowledge of the sort of process that has led to life here on Earth, regardless of whether Titan itself actually has life or not.

[Cosmologist]

The question of whether alien life exists is unimportant. It undoubtedly does. Life is straightforward chemistry. It happened here so it can happen elsewhere. This universe is so big we have no idea at all how far it goes. Our telescopes can only see 14 billion light years tops. Or whatever the latest educated guestimate is for the age of the universe. We are also looking back in time so nothing we see is up to date. Millions of Dyson Spheres or other massive engineering projects could be surrounding us and we might not get the first hint for billions of years as thats how long it might take the light to reach us. The question is whether advanced life exists within reach of us. We are in a race with every other advanced life form to colonise the universe.

[Paul Wally]

That's another possibility to consider, yes... But how would we conduct such a search?

I mean, a search in the realm of possibility, not empirical search. So it requires the kind of broad speculative thinking and imagination of a science fiction writer to answer the question: "What form of inter-stellar communications would a civilization a million years ahead of us use?". I believe that the search for extra-terrestrial intelligence is one area of research where thinking outside of the conventional paradigm may be quite necessary.

[Cougar]

The question of whether alien life exists is unimportant. It undoubtedly does. Life is straightforward chemistry. It happened here so it can happen elsewhere.

It can happen elsewhere, but has it? We have no confirming evidence. I speculate that you are right, especially based on Stuart Kauffman's investigations into the chemistry, which is not all that straightforward. (If it was that straightforward, why can't we do it?)

As you say, with the number of galaxies in the universe, the "odds" are awfully good that there is life elsewhere. But even so, statistically speaking, it is difficult to reach conclusions based on a sample population of 1, which is all we've got for "planets with life."

[Selfsim]

... But even so, statistically speaking, it is difficult to reach conclusions based on a sample population of 1, which is all we've got for "planets with life."

Well, its statistically invalid to reach any definitive conclusion based on a sample population of 1!

Cheers

[Selfsim]

I mean, a search in the realm of possibility, not empirical search. So it requires the kind of broad speculative thinking and imagination of a science fiction writer to answer the question: "What form of inter-stellar communications would a civilization a million years ahead of us use?".

Well, there goes the neighbourhood …

I believe that the search for extra-terrestrial intelligence is one area of research where thinking outside of the conventional paradigm may be quite necessary.

Well that would be because the initial postulation itself, is already not founded in reality ... so just change the postulate!
Problem solved .!. ta da!!

[Noclevername]

Well that would be because the initial postulation itself, is already not founded in reality ... so just change the postulate!
Problem solved .!. ta da!!

How is a possibility not in the realm of reality? Isn't the whole point of science to investigate possiblities?

[Selfsim]

How is a possibility not in the realm of reality? Isn't the whole point of science to investigate possiblities?

Many things are possible in theory, and I don't think anyone would reasonably deny theoretical scientific postulations as being possible (within the realm of theory).

The 'reality' I speak of is physical reality which is distinguished by being measurable in distance, time and form. (Independently verifiable, etc)

I can't measure things, (or their effects), such as: exo-life, interstellar spacecraft, FTL neutrinos etc, so they cannot be demonstrated to exist in physical reality.

[Noclevername]

I can't measure things, (or their effects), such as: exo-life, interstellar spacecraft, FTL neutrinos etc, so they cannot be demonstrated to exist in physical reality.

And we'll never know if those things exist or not, or can be made to exist, without investigation. Science is a process, not a body of dogma. It's about taking what's unproven, trying to prove it, and either proving it or not.

SETI isn't about demonstrating that ETI exists, it's about trying to find out if it exists, at least in a form recognizable to us. The postulate is not "if there's life it'll be transmitting radio", but rather "if we recieve radio that is clearly artificial, it'll be evidence of life".

[cosmicrockstar]

When it comes to planets in the universe i would think microbial single celled life is common as it can withstand a different range of temperature. It seems however that complex life can only tolerate so much heat and cold. I mean if you put a person in the middle of the sahara he or she would only have a few hours of survivability.

[Selfsim]

I can't measure things, (or their effects), such as: exo-life, interstellar spacecraft, FTL neutrinos etc, so they cannot be demonstrated to exist in physical reality.

And we'll never know if those things exist or not, or can be made to exist, without investigation. Science is a process, not a body of dogma. It's about taking what's unproven, trying to prove it, and either proving it or not.

I don't agree that physical science is about 'proving' or 'disproving' anything!
'Proof' is for mathematicians and courts of law. There is no truth in physical science .. so no 'proofs'.

… And some of those things (like exo-life) cannot be practically falsified. (It is not possible to search the entire observable universe in order to falsify the hypothesis of the existence of carbon-based exo-life .. so its not a practically testable hypothesis). It is possible to verify it by a chance discovery, however. Chance discoveries require only exploration within feasibly reachable targets (like SETI). Outside of feasibly reachable targets, conclusions require inference based arguments which don't result in evidence, because they cannot eliminate what is not yet known.

SETI isn't about demonstrating that ETI exists, it's about trying to find out if it exists, at least in a form recognizable to us. The postulate is not "if there's life it'll be transmitting radio", but rather "if we recieve radio that is clearly artificial, it'll be evidence of life".

Same as if we see ET's face staring into a rover's camera and poking its tongue out! That would certainly constitute hard evidence of a face ... and a tongue!

[cosmicrockstar]

I would think there is mostly microbial life and that complex life is rare.

[Colin Robinson]

I mean, a search in the realm of possibility, not empirical search. So it requires the kind of broad speculative thinking and imagination of a science fiction writer to answer the question: "What form of inter-stellar communications would a civilization a million years ahead of us use?". I believe that the search for extra-terrestrial intelligence is one area of research where thinking outside of the conventional paradigm may be quite necessary.

How's this for a piece of speculative thinking?

A million-year-old civilization would have learned patience. Perhaps, if they wanted to communicate with other civilizations, they would send a very, very slow signal, by working with a natural phenomenon (like a variable star) and making its output change every 50 years or so.

The advantages of this method:

1. The slowness of the message would make it more likely to be "heard" by another civilization with the technology and the inclination to observe stars carefully over the long term. It would be less likely that the message would be missed (in whole or in part) simply because the recipients were not observing the right star at the right moment.

2. The message would only become apparent via prolonged observation. It might take hundreds of years of observation to establish that it is a message, and then thousands of years to make some sort of sense of it. A civilization that rapidly destroys its own environment -- a civilization in boom-bust mode -- would be unlikely to recognize the message as a message. Perhaps the million-year-old civilization would see that as an important advantage...