Our galaxy has exoplanets, organic compounds, liquid water -- even a nebula shaped like a DNA helix -- but is there life? (Image credit: M. Morris/UCLA)

Alien Life May Not Be So Alien – If It Exists At All

9 May , 2012 by

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Are we too hopeful in our hunt for extraterrestrial life? Regardless of exoplanet counts, super-Earths and Goldilocks zones, the probability of life elsewhere in the Universe is still a moot point — to date, we still only know of one instance of it. But even if life does exist somehow, somewhere besides Earth, would it really be all that alien?

In a recent paper titled “Bit by Bit: the Darwinian Basis for Life” Gerald Joyce, Professor of Molecular Biology and Biochemistry at the Scripps Research Institute in La Jolla, CA discusses the nature of life as we know it in regards to its fundamental chemical building blocks — DNA, RNA — and how its ability to pass on the memory of its construction separates true biology from mere chemistry.

“Evolution is nothing more than chemistry plus history,” Joyce said during a Public Library of Science podcast.

The DNA structures that evolved here on Earth — the only place in the Universe we know for certain that life can thrive — have proven to be highly successful (obviously). So what’s to say that life elsewhere wouldn’t be based on the same basic building blocks? And if it is, is it really a “new” life form?

“Truly new ‘alternative life’ would be life of a different biology,” Joyce said. “It would not have the information in it that is part of the same heritage of our life form.”

To arise in the first place, according to Joyce, new life can take two possible routes. Either it begins as chemical connections that grow increasingly more complex until they begin to hold on to the memory of their specific “bit” structure, eventually “bit-flipping” — aka, mutating — into new structures that are either successful or unsuccessful, or it starts from a more “privileged” beginning as an offshoot of previous life, bringing bits into a totally new, immediately successful orientation.

With those two scenarios, anywhere besides Earth “there are no example of either of those conditions so far.”

That’s not saying that there’s no life elsewhere in the Universe… just that we have yet to identify any evidence of it. And without evidence, any discussion of its probability is still pure conjecture.

“In order to estimate probabilities, we need facts,” said Joyce. “The problem is, there is only one life form. And so it’s not possible to estimate probability of life elsewhere when you have only one example.”

Voyager included a golden record with images and sounds of Earthly life recorded on it... just in case. (NASA)

Even though exoplanets are being found on a nearly daily basis, and it’s only a matter of time before a rocky, Earthlike world with liquid water on its surface is confirmed orbiting another star, that’s no guarantee of the presence of alien life — despite what conclusions the headlines will surely jump to.

There could be a billion habitable planets in our galaxy. But what’s the relationship between habitable and inhabited?” Joyce asks. “We don’t know.”

Still, we will continue to search for life beyond our planet, be it truly alien in nature… or something slightly more familiar. Why?

“I think humans are lonely,” Joyce said. “I think humans are like Geppetto — we want to have a ‘real boy’ out there that we can point to, we want to find a Pinocchio living on some extrasolar planet… and then somehow we won’t be such a lonely life form.”

And who knows… if any aliens out there really are a lot like us, they may naturally be searching for evidence of our existence as well. If only to not be so lonely.

Listen to the full PLoS podcast here.

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Bobr
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Bobr
May 9, 2012 7:30 PM

Re: “we want to have a ‘real boy’ out there that we can point to, we want to find a Pinocchio living on some extrasolar planet…”

Wouldn’t finding life on Mars answer that question?
It sure would satisfy me!

Peter
Member
Peter
May 10, 2012 12:05 AM

No, Z, because if we find there WAS life on Mars then we’re still alone and if we find there IS life on Mars, then it’s a simple bacteria or some such that leaves us still feeling pretty much alone as the only multicellular lifeforms. Besides, unless it’s some extraordinary cellular structure, then I would conjecture that it had every right to come from here anyway. Afterall, the moon very possibly came from here and that’s a lot of earth rock in space.

Bobr
Member
Bobr
May 10, 2012 4:21 AM
That might make YOU still feel alone if a lower life-form was found on Mars, but not me! I guess what level of life would get you excited is subjective. (If found, two out of eight planets, and several potential moons ain’t bad odds for the rest of the galaxy.) Peristroika wrote: “unless it’s some extraordinary cellular structure, then I would conjecture that it had every right to come from here anyway.” I’m not sure I understand that – Considering the sentence following that one, do you mean that when our Moon was formed as per the current accepted hypothesis of another Mars-size object striking Earth, that debris scattered into space and seeded Mars? All models I’ve read… Read more »
Peter
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Peter
May 10, 2012 12:32 PM
Point well taken. Yes, presumably, that was well before life started but transpermia seems always to be discussed in the “to earth” direction and yet, we know WE’VE got it, so if we can guess at what direction it might go in, well, outward is our only fact-supported direction. Just saying, Mars wouldn’t necessarily prove anything. Unless, as I say, it is a left handed organism or built on something other than RNA or DNA. As for the other moons, they are undoubtedly interesting but clearly, what we’re seeing is that many planets or planetary bodies harbour life-useful systems but that goes without saying with the billions of potentials in our galaxy alone. Here’s hoping and yes, I’ll… Read more »
bfmorris
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bfmorris
May 11, 2012 5:07 AM

“Just saying, Mars wouldn’t necessarily prove anything. ”

I pretty much agree; I’m too uncomfortable with Mar’s relative proximity to earth to call it a litmus in the case for alien life.

Though I’m excited about this August, of course non the less.

Lawrence B. Crowell
Member
Lawrence B. Crowell
May 11, 2012 10:23 PM

If martian DNA were sequenced and found to express polypeptides completely different from what is found with Earth life it would give weight (not proof) these organisms started unquely from Earth life.

LC

David Carlson
Guest
May 9, 2012 8:09 PM

Or more likely, life here was seeded by Panspermia even to the extent of incorporating entire gene sequences for higher traits from interstellar/intergalactic microorganism contaminates, such that localized evolution may be more a process of cutting, pasting and adapting pre-existing genetic material rather than evolving it from scratch.

If so then life is far more complex than anything that could have arisen on a solitary planet as suggested by creationists.

Torbjorn Larsson OM
Member
Torbjorn Larsson OM
May 9, 2012 10:55 PM

Panspermia, interstellar transpermia, is not likely at all AFAIK. Dormant genetic material is broken down without repair in geologically short order from cosmic radiation if transported outside of terrestrial bodies and from radioactivity if transported inside.

Hans Peter Uhrig
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Hans Peter Uhrig
May 10, 2012 7:51 AM

It may be better to overestimate life than to underestimate it like this example (also in regards to the panspermia theories) shows:
http://en.wikipedia.org/wiki/Deinococcus_radiodurans
“D. radiodurans is capable of withstanding an acute dose of 5,000 Gy of ionizing radiation with almost no loss of viability, and an acute dose of 15,000 Gy with 37% viability.”

http://biospace.nw.ru/astrobiology/Articles2002/Astrobio_pavlov_25-34.pdf

damian
Member
May 10, 2012 9:33 AM

Unless of course Panspermia is not random. Directed Panspermia isnt that far fetched. The human species is reaching out to space atm.

Put a human on Mars and we will be the instruments of directed panspermia on another world.

Humans are n ecosystem of microbiology that we may safely transport over the vast distance in a (protected craft) and deliver them safely and alive to another planet.

= directed panspermia

Hans Peter Uhrig
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Hans Peter Uhrig
May 10, 2012 11:21 AM

We probably already done so (directed panspermia) by sending not really sterilized spacecraft to Mars after and even before the Vikings (eg Russian spacecraft). In regards to Mars I would assume a not isolated common biosphere which we already have some hints off (Viking life-detection and Martian meteorites) . Cross-contamination may have happened before us already and chances are that Martian life (extinct and extant) is related to Earth life in some way.

Torbjorn Larsson OM
Member
Torbjorn Larsson OM
May 10, 2012 8:46 PM

Not very likely.

– If Mars is (was) habitable, life evolved there by itself. Mars aggregated way before Earth, ~ 4 million years as opposed to ~ 40 – 60 million years. (If the new Sm clock rates are accepted.)

Then we have the subsequent sterilizing Earth-Moon impactor, likely somewhere 180 million years ago. (Another recent re-dating.)

– It is highly unlikely such life could have transported to Earth, and even if there would be a small likelihood – the time window before life evolved here wasn’t large. Some abiogenesis theories claim 10’s of thousands of years as upper limit. Mars-Earth transported impactors aren’t that frequent.

Hans Peter Uhrig
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Hans Peter Uhrig
May 11, 2012 8:09 AM

“If Mars is (was) habitable, life evolved there by itself.”

That would be the most important finding of science ever – strangely nobody seems to realize this and no real attempts have been made to follow up the Viking results to date. A comparable cheap and miniature chiral version of the proven Viking LR experiment could yield some astonishing data in this regards. Fortunatly such has been proposed as part of the BOLD mission concept which could fly in 2018 – just only 42 years after Viking(!) smile

Hans Peter Uhrig
Guest
Hans Peter Uhrig
May 10, 2012 11:21 AM

We probably already done so (directed panspermia) by sending not really sterilized spacecraft to Mars after and even before the Vikings (eg Russian spacecraft). In regards to Mars I would assume a not isolated common biosphere which we already have some hints off (Viking life-detection and Martian meteorites) . Cross-contamination may have happened before us already and chances are that Martian life (extinct and extant) is related to Earth life in some way.

Torbjorn Larsson OM
Member
Torbjorn Larsson OM
May 10, 2012 8:41 PM

First, D. radiodurans has a one off repair trait, phylogenetic work has managed to show that it is a side effect of having evolved a special stress response to survive severe drought.

Don’t expect it to be common, and don’t expect it to evolve among more ancestral cells.

Second, as I said earlier this repair mechanism doesn’t work in space. Eventually its DNA will be too fragmented and its cellular machinery too damaged to make a successful repair.

marlon david
Guest
May 9, 2012 8:13 PM

there is no alien life… and this is the stand of universe today eversince… it must not change…

kwestdjonmaarc
Member
kwestdjonmaarc
May 9, 2012 10:01 PM

i find this article…disturbing…mainly because the best thing the author can come up with is “I think humans are lonely”.

Torbjorn Larsson OM
Member
Torbjorn Larsson OM
May 9, 2012 10:39 PM
Gerald Joyce wrote an obituary of Leslie Orgel, who famously couldn’t see how chemical evolution achieves catalytic closure as in cells. I’ll have to read the paper, but the hypothesis that there is a qualitative phase change between distributed chemical evolution and its progress to localized reproduction in cells is not very predictive and has not been tested as of yet. The more parsimonious hypothesis is that there was a gradual localization and increase of inheritance. And as I always complain, and it could be the case here, information is relative a system and a chosen measure, there is no inherent quality associated with it. the probability of life elsewhere in the Universe is still a moot point… Read more »
bfmorris
Member
bfmorris
May 10, 2012 1:31 AM

“”This deterministic looking as opposed to stochastic looking phase space should give supporters reason to pause!””

How would this square with our stochastic universe?

Life appears similar to the invisible dark matter I read about. We can’t see it, we can only observe its effects. It appears life is invisible; some kind of invisible management system or program, for lack of better word. We can only observe its effects. In this case, what appears to be invisible employment of organised chemistry that among other things, temporarily outwits the second law of thermodynamics.

Torbjorn Larsson OM
Member
Torbjorn Larsson OM
May 10, 2012 8:33 PM

There are plenty of deterministic processes out there. Planetary orbits, star evolution main series, et cetera are short period deterministic. Or you can narrow it down to impact shocks (real short period) and so on.

I can’t follow your argument in the middle part. The biosphere is plenty observable.

The thermodynamics is all wrong, there is no TD problem. You could as well say that refrigerators outwit TD.

bfmorris
Member
bfmorris
May 11, 2012 3:37 AM
re the middle part: What I mean is, and I’m not arguing with you, it appears thus far that the most we can observe is life’s effects; ie on the matter it employs. The atoms in you or me are the same atoms found elsewhere. There is nothing special about them, and we would not be able to differentiate the atoms in us from those in a rock or a rain drop. However, no matter how many times we throw atoms in the proverbial air, we can’t recreate what we observe. The effects on those atoms, by life, are all we have at present for the observation of life. Thus my dark matter analogy, partly in levity, because… Read more »
wjwbudro
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wjwbudro
May 11, 2012 2:02 PM

Very intuitive. I’d like more discussion on this thought.

TheMatrixDNA
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TheMatrixDNA
May 16, 2012 1:11 AM
Very intuitive, Mr. “bfmorris”. As wjwbudro, I’d like more discussion on this thought. Why atoms behaves different in living organisms? I think the answer is in the hierarchy of natural systems. Must be an invisible natural system inserted inside these atoms and acting from above over them, changing its normal behavior when free. The most clear example is the system of religion acting from and over a biological system called human being: the normal fighting for survival can became a suicide bomber. Or sun’s flares over Earth magnetic field. Then we have Matrix/DNA Theory models suggesting how a galactic system is half-mechanical/half-biological and how its building blocks are like nucleotides, and, how the laws and behaviors of this… Read more »
tareece
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tareece
May 10, 2012 2:32 PM
You knowwww, it’s people like Mr. Larson that give me goose pimples. (And I mean that in the best and most respectful manner). I can only truly sit and wonder about the actual mathematical “brass tacks” that dissolve all the factors down to single basic equation. I hope you sit back and truly consider yourself lucky and fortunate to orchestrate your abilities into a concise and readable form to laymen like myself. All that jargon and mathematical wizardry to say what seems readily obvious… Some magical power made all the nuances and accidents come together…here. Such coincidences in such a vast universe would be deemed what mathematically? In a more philosophical way, in the debate whether or not… Read more »
arthur_gould
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arthur_gould
May 9, 2012 10:57 PM

Microbial life most likely is under the soil on Mars. It is probably in Europa’s ocean. The Universes’ purpose is to harbor life. Come on people, My glass is half full… of a great Stout!!!!! Booooyaaaahhh!!!!!

(Created by microbial life- Yeast)

dwdeclare
Guest
May 10, 2012 2:39 PM

universe’s purpose? the universe needs neither life nor a purpose to exist. it may perhaps be inevitable that given unlimited time and unlimited space, with all manner of physical processes stirring and mixing chemistry about, sentient life will arise sometime, somewhere in the vast expanse, but that in no way implies that the universe is somehow fulfilling it’s “purpose”. teleological final causes are the stuff of fairy tales, fantasy and religion…not science.

the universe doesn’t have a purpose but we do. and it’s to drink beer on saturday afternoons eating nachos while watching 5-pin bowling on a big screen tv. it don’t git no better than that!

The Bobs
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The Bobs
May 9, 2012 9:15 PM

“The amino acids that form DNA here on Earth”

DNA does not contain any amino acids.

arthur_gould
Guest
arthur_gould
May 9, 2012 9:59 PM

adenine (abbreviated A), cytosine (C), guanine (G) and thymine (T)

Torbjorn Larsson OM
Member
Torbjorn Larsson OM
May 9, 2012 10:51 PM
Those are the nucleobases that goes into the DNA nucleotides. My take was that “the amino acids that form DNA here on Earth” is a description of the cellular machinery, of mostly proteins, that produce DNA. Those cells have been successful indeed, having survived for ~ 4 billion years and as it looks relegated their RNA cell ancestors to parasitic virus niches*. —————- Since the Virus domain is polyphyletic, has last common ancestor outside the group on account of some groups having closer affinities to Eukaryotes, Archaea, and Bacteria respectively, some people describe it as a possible niche of parasites. Some DNA viruses seem to be extremely parasitically simplified descendants of cellular life forms, some may be de… Read more »
Jason Major
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May 9, 2012 11:12 PM

You’re right. Reworded for better accuracy.

bgrggfe
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bgrggfe
May 10, 2012 3:17 AM

According to the survey, France has about 2.6 million millionaires,that is most in European countries .After the Outlander win the presidential election , Maybe the rich will fear the outbreak of the exodus. In fact, many multinational corporations before the election, one after another continued to headquarters out of Paris, the transfer tax rate is relatively low, Luxembourg, Hong Kong, even the United Kingdom. ”
Well-known French brand Louis Vuitton Handbags On Sale boutique group LVMH , also reported to consider To the headquarters moved to London from Paris, it is necessary to avoid heavy taxes, and increased high tax rates make LV headquarters in Paris, it is difficult to find the Senior Management .

bgrggfe
Guest
bgrggfe
May 10, 2012 3:01 AM
Worldwide more than $100 billion worth of counterfeit products, from Louis Vuitton Replica Handbags to Rolex watches, are sold every year. I have developed a great idea, which will allow shoppers to check the authenticity of the product by using their smartphone before they buy the Louis Vuitton Replica. It will add only a fraction of the cost of the product for the manufacturer, who will be more than happy to pay this little extra cost to protect their brand and increase their sales. However, I do not yet have a working prototype, which requires significant investment. I do not know how and who to approach for venture capital funding. I am so confident about the success of… Read more »
bgrggfe
Guest
bgrggfe
May 10, 2012 3:20 AM

Louis vuitton sent their fall/winter 2012/2013 collection down the Milan Fashion Week runway today and it featured a much darker, more gothic and vampire-like color palette than what was shown by the iconic design house for fall 2011. One year
ago louis vuitton Handbags showed bright colors and blocked them together, helping to explode the current color blocking trend. For fall 2012, Gucci moved away from the trend they started and let black rule the runway.

Manfred Higgs
Guest
May 10, 2012 8:40 AM
Considering the scope of our knowledge universally speaking saying that we haven’t found any evidence and hence must assume at least for now that we are alone is a little ridiculous. The media often makes it seem like we have this amazing view of the cosmos but in reality we look at tiny sections and any kind of overall view we have is extremely general. The area of the universe that is actually observable as far as searching for evidence of life goes is so tiny it’s like dropping your keys on the beach checking under your foot and saying that that because they are not under your foot we must for the moment assume they are not… Read more »
squidgeny
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squidgeny
May 10, 2012 11:42 AM

saying that we haven’t found any evidence and hence must assume at least for now that we are alone is a little ridiculous.

No; it’s a valid application of the scientific method. Nothing exists until there’s evidence for it.

valles
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valles
May 15, 2012 7:33 PM

Like Black Swans?

valles
Guest
valles
May 15, 2012 7:33 PM

Like Black Swans?

Dunc Kaas
Guest
May 10, 2012 10:53 AM

This was in last seasons Through the Wormhole already razz

Tim Tomakin
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Tim Tomakin
May 10, 2012 7:32 AM

The problem is that they are searching for life as we know it, using the chemistry of the human race. We only know what we’ve learned from this planet, the chemical makeup of other galaxies or life forms can easily be very different from anything we know about. This close mindedness disappoints me coming from scientists who are aware of how vast space is.

Dunc Kaas
Guest
May 10, 2012 11:00 AM

Actually, they’re looking for communication aswell, as from studies has showed that all communications have the same basic principles (between the higher life forms) and that dolfins and the like follow the same ‘similarities’ in their communcation as human languages. So that even if we cannot understand or unscramble a language, in theory we should be able to spot communication from background noise. As alien or not, they are bound to the laws of physics as are we. (or maybe not, but no use looking for something if we dont have a clue what to look for razz)

Peter
Member
Peter
May 10, 2012 12:38 PM

Yeah, we’ve looked at galaxies billions of years distant and seen the signature of chemistry we know and understand. Since chemistry follows physics and physics seems to be universal, scientists are working with a solid set of conjectures as opposed to you who would like to think we know nothing and so can guess at anything.

bfmorris
Member
bfmorris
May 12, 2012 4:10 PM

With the debunking of the arsenic story, how do we know your statement “the chemical makeup of other life forms can easily be very different from anything we know about” to be true? What other elements have the same properties as our life forms?

Lawrence B. Crowell
Member
Lawrence B. Crowell
May 10, 2012 2:08 PM
If something is not absolutely forbidden by physical principles it is then mandatory. The lack of some physical impossibility for a state means this state exists in the set of possible states in the universe. In that state space there is some measure, whether that be an orbit space, orbifold or a probability distribution which can estimate the frequency with which that state occurs. Life in the universe in a natural philosophical sense is not likely to be forbidden. One might maintain that life on Earth is some fluke of happenstance which permitted something with zero probability to occur. Some would argue that fluke is a supernatural intervention. We might say that if the universe is infinite that… Read more »
tareece
Member
tareece
May 10, 2012 3:11 PM
lc, What I would like to know, and it seems obvious to me, if there were ‘accidental’ and luckiness in our planets ability to have life… what about the numerous extinction events and the fact that while scientists agree that comets and the like carried life giving and other elements necessary for life.. all the while most incoming comets/asteroids have been gobbled up by the outer gas planets, especially Jupiter? Perhaps your equation takes this into consideration, but with ‘super Earths’ being found, wouldn’t it be plausible that they too would be impacted by these life-giving rocks and thus seeded at a higher rate than we have been? I see from further reading of your post, you do… Read more »
Lawrence B. Crowell
Member
Lawrence B. Crowell
May 10, 2012 10:18 PM

A solar system is actually a deterministic system. However, there are sensitive dependencies on initial data, aka chaotic dynamics. Knowledge of that determinism requires an infinite floating point precision. The problem of course is that out to 10^{30} decimal points a computer that occupies a 10^6m^3 volume that processes this volume of data will implode into a black hole. So the determinism of nonlinear classical systems is really an idealization.

LC

ToddReece
Guest
May 10, 2012 11:10 PM

yeahhh, ofcourse … I was asleep during that class.

Lawrence B. Crowell
Member
Lawrence B. Crowell
May 11, 2012 1:50 PM

Information has a connection to energy and entropy by the Shannon-Khinchin theorem. If you had a computer that could accumulate ever greater amounts of information the energy equivalent would be so large at some point that it would have sufficient gravity to become a black hole. Strange, it is true, but this universe is stranger than we often at first think it is.

This also means that observables in the universe can never be measured with complete certainty, even if you expand the uncertainty in the conjugate variable arbitrarily large. The number of degrees of freedom we can describe in the universe in some complete manner is far smaller than we currently think they are.

LC

bfmorris
Member
bfmorris
May 11, 2012 5:08 PM

Does the universe by definition have to be finite, because it has a beginning? Thus is the information contained in it, is finite, though ever growing thus eventually the blackhole?

Lawrence B. Crowell
Member
Lawrence B. Crowell
May 11, 2012 1:50 PM

Information has a connection to energy and entropy by the Shannon-Khinchin theorem. If you had a computer that could accumulate ever greater amounts of information the energy equivalent would be so large at some point that it would have sufficient gravity to become a black hole. Strange, it is true, but this universe is stranger than we often at first think it is.

This also means that observables in the universe can never be measured with complete certainty, even if you expand the uncertainty in the conjugate variable arbitrarily large. The number of degrees of freedom we can describe in the universe in some complete manner is far smaller than we currently think they are.

LC

bfmorris
Member
bfmorris
May 10, 2012 8:05 PM
I’m unclear how infinity would work. Can bona fide infinity have a beginning, or does bona fide infinity require no beginning and no end? Also what about, say, something that has a beginning point and an end point, but never before occurred and doesn’t ever reoccur for infinity or forever, for lack of a better word? Does infinity even really exist outside of our minds? I’m also unclear (re the recent thread about math being more than just man made) how mathematics can be universal in a stochastic universe. We’re using math to predict the existence of ET, but does the universe really owe us mathematical odds? If the universe is mathematical, it seems the answer is yes,… Read more »
Lawrence B. Crowell
Member
Lawrence B. Crowell
May 10, 2012 10:12 PM

Stochasticity is a branch of mathematics. This also gets into questions about Kolmogoroff entropy and the indefinability of randomness. If time permits later today or tomorrow I might expand on this point.

Does the universe owe us mathematical odds? That depends, but from a Bayesian perspective the update of a Bayesian prior can be seen as our acquisition of increased data. The frequentist perspective is one where there exists a defininate ensemble with a distribution of probabilities.

LC

bfmorris
Member
bfmorris
May 11, 2012 5:03 PM

“”Stochasticity is a branch of mathematics. This also gets into questions about Kolmogoroff entropy and the indefinability of randomness. If time permits later today or tomorrow I might expand on this point.””

Does infinity’s definition represent the same indefinability?

Lawrence B. Crowell
Member
Lawrence B. Crowell
May 11, 2012 6:24 PM
Infinity turns out to be strange with a hierarchy of infinities. The lowest infinity is uncountable infinity ?_0 and the next level ?_1 = 2^{?_0} is uncountable infinity. These are a part of George Cantor’s transfinite numbers. This formula however is not proven and is the continuum hypothesis (CH). Bernays and Cohen demonstrated this is not provable within the ZF set theory using Godel’s theorem. Better said they found a form of Godel’s theorem that demonstrated the truth of the CH, but that it is unprovable. There exists a hierarchy of these transfinite numbers ?_n, and even ?_?, which leads to a new class of even more infinite numbers called least inaccessible cardinals. In fact the set theory… Read more »
bfmorris
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bfmorris
May 14, 2012 6:39 AM

So you’re saying, infinity exists as long as there are humans around to hypothesise it.

Lawrence B. Crowell
Member
Lawrence B. Crowell
May 14, 2012 2:25 PM

Infinity is not really a number, but a set or a set with ordinality and cardinality. The Cantor transfinite numbers are used to distinguish infinities (or sets that are non-finite) by ordinal and cardinal structures.

Whether infinity exists, or any mathematical object exists, independent of a human mind gets into some issues with the philosophy of mathematics. I don’t tend to worry that greatly about these matters. I am not sure questions along these lines have a provable answer, and frankly I think these questions diverge too far from my principal interests.

LC

Torbjorn Larsson OM
Member
Torbjorn Larsson OM
May 10, 2012 8:59 PM

Thanks for noticing and responding.

Yes, we can use more statistic machinery if we wish. But then we leave the tested model and replace it with a weaker, untested model.

The only reason to do that would be if we know that there are dominant pathways for chemical evolution that are somehow radically different. Baring that, it isn’t a very good working hypothesis IMHO. Quite the contrary, many organic compounds found in meteorites et cetera are mundane and comparable to what metabolism uses here. (Amino acids et cetera.)

Lawrence B. Crowell
Member
Lawrence B. Crowell
May 10, 2012 10:20 PM

If these statistics are used to estimate priors, then the application of knowledge about possible chemical pathways can be used to update those priors. Until we find the big cahuna this is the best we can do.

LC

andrew g
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andrew g
May 10, 2012 5:21 PM
“If something is not absolutely forbidden by physical principles it is then mandatory. The lack of some physical impossibility for a state means this state exists in the set of possible states in the universe.” There is nothing in the laws of physics to prevent me being selected as captain of the England football team. I am 49, overweight, unfit and never played the game professionally, or at any great standard, but there is nothing to stop the manager picking my name out and asking me. So is this mandatory in some corner of the multi(?)verse? Remember, not only do I have to be selected, but the locals there also have to think this is completely logical. In… Read more »
Lawrence B. Crowell
Member
Lawrence B. Crowell
May 10, 2012 10:06 PM

This situation might have to involve multiverse or many worlds considerations. However, while it is exceedingly unlikely that you will become a captain of an football team, or that I get drafted as quarterback for the New England Patriots, it is not impossible in the same sense as trying to exceed the speed of light.

LC

dwdeclare
Guest
May 10, 2012 3:01 PM
it’s not so much that “we want to find a pinocchio living on some extrasolar planet” but that we want to find a bambi so we can murder his mother. humans are born soulless killers, lacking any empathy for the suffering of another, all so they can temporarily make a quick profit. let us not forget the wise words from the 29th scroll, 6th verse: “beware the beast man, for he is the devil’s pawn. alone among god’s primates, he kills for sport or lust or greed. yea, he will murder his brother to possess his brother’s land. let him not breed in great numbers, for he will make a desert of his home and yours. shun him;… Read more »
Torbjorn Larsson OM
Member
Torbjorn Larsson OM
May 10, 2012 8:22 PM

A bit too much Corny-elius for my taste.

As for morals, we are born with it according to extensive research. Notably for amoralist theoreticians is also that precisely Homo is the peaceful ape, all the rest are natural born killers. (Even gorilla’s practice infanticide.)

dwdeclare
Guest
May 10, 2012 9:10 PM

Homo is the peaceful ape?

Man is a nuisance. He eats up his food supply in the forest, then migrates to our green belts and ravages our crops. The sooner he is exterminated, the better. It’s a question of simian survival.

valles
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valles
May 15, 2012 7:26 PM

EH???

valles
Guest
valles
May 15, 2012 7:26 PM

EH???

jjb
Member
jjb
May 10, 2012 4:53 PM

I had a Prof that had a great quote – All the equations in the world, are easily wrote and even quicker to be erased at the end of the day or week. Then a new equation will be devised. In the end they are all dust on an eraser.

All the math equations about life out there are “dust on an eraser” until we actually find life.

Then again, what do we mean? Life as INTELLIGENT or Life as Microbial? Either would be significant to be sure.

But the odds of Intelligent Life? I think we are going to find it unanswered for yet a few 100 more so years …. The evidence as of yet is simply not there!

Torbjorn Larsson OM
Member
Torbjorn Larsson OM
May 10, 2012 8:19 PM

Models are not “math equations” but testable hypotheses. That is something entirely different.

Based on observations I claim that we know a whole lot on life, and actually enough to estimate likelihood. (Until more observations will evolve the area.)

jjb
Member
jjb
May 10, 2012 9:54 PM

“testable hypotheses” – Okay, so one planet (ours) is the only ‘test’ we have. We have no other planets for which to test this “hypothesis”. So there is a 50/50 chance that it is wrong or right ….. Time will tell. Heck, I’m not even sure we can call it a Hypothesis, to be honest, let alone a model.

Because right now – the only evidence/proof we have of Intelligent Life is us.

hionthemountain
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hionthemountain
May 10, 2012 6:27 PM

The odds of other life in the universe are better than the possibility that there isn’t . . .

andrew g
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andrew g
May 10, 2012 5:33 PM
Turn the question round. If there is advanced life out there somewhere then we are the alien life that they might right now be searching for. On the principle that there is nothing special about us or our corner of the universe then it follows that any other beings must also be pretty much like us, watching tv, fighting wars, browsing their internet etc, or close equivalents. Since physical properties on these “Earth-like” planets are going to be similar, chemistry works the same way wherever you are – we have already detected organic molecules in deep space – once evolution gets going it is going to find the same solutions as it did on Earth. Eyes have evolved… Read more »
Torbjorn Larsson OM
Member
Torbjorn Larsson OM
May 10, 2012 8:12 PM

That is pretty much what most biologists have concluded will _not_ happen.

Eyes likely, legs perhaps – but traits like linguistically capable brains will happen once in a blue moo… planet. The elephant trunk only evolved once, the Homo brain only evolved once, the narwhal tooth only evolved once, eukaryotes and so the possibility of complex multicellulars only evolved once et cetera.

If you ask biologists complex multicellulars will be exceedingly rare, and linguistic capability comparably rare among worlds with complex multicellulars.

bfmorris
Member
bfmorris
May 12, 2012 3:53 PM
Eyes have their beginnings from sight specific control genes that are present in all life, as I understand it. andrew g wrote: ” On the principle that there is nothing special about us or our corner of the universe ” ‘Us’ looks special to me. I think a discussion of what constitutes special, would be interesting. Is uniqueness a component of special? If a US coin mint had struck only one of a certain gold coin or even a few of them due to whatever circumstances, are not those coins then considered ‘special’ and sought after by collectors? If there is only one andrew g in the universe, no other made exactly like him, it seems that single… Read more »
Jeremy
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Jeremy
May 10, 2012 10:18 PM

If you think that the odds are in favor of their not being other intelligent life then you need an MRI. Seriously.

DrArbind Kumar
Guest
May 15, 2012 4:49 PM
DNA Nebula, as I prefer to call it, might have been formed and shaped under the influence of gravity. Biomolecule DNA, the blueprint of life, also might have been formed and shaped under the influence of gravity.The following equation derived by me strongly suggests the correlation between DNA and our Solar System, thus indicating the influence of gravity in the formation and shaping of DNA. 64 – As 339 —————– = ————— 20 107.65 Where, 64 = Number of codons 20 = Number of amino acids As = Astromolecular constant i.e. 1.013, derived during the present Investigation 339 = Number of disks of Sun to measure its apparent path along the ecliptic in Celestial sphere between the two… Read more »
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