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Life in our galaxy


spurius
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Or what about a completely different size scale? The solar system a mere atom and galaxies just molecules within an insignificant pea on the fork of another being in a universe which makes ours look tiny

Makes ya think dunnit?

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The Drake equation implies that the Universe should be teeming with life. The Fermi paradox states that there is a contradiction between the large estimates of the probability of ET civilizations and the obvious lack of evidence or contact with.

What is often not taken into account however, is the length of time any given species (technological or not) will survive on any given planet.

We need to keep in mind the time scales involved.

Lets take a look at the development of life and then  technology on our own planet,

The universe started some 13.6 billion years ago.

The earth is some 5 billion years old.

Single cell life forms (prokaryotes) developed 3.6 billion year ago.

Complex cell forms  (eukaryotes) developed 2 billion years ago.

Land plants have been around for only 475 million years.

The dinosaurs first evolved 230 million years ago (lasted until about 65 million years ago).

Homoerectus (modern mans precursor) only started to exist 1.9 million years ago.

Current estimates for the first appearance of Homosepiens (modern man) are between 130 000 to 190 000 years ago in Africa.

The Sumerians are thought to be the first 'modern' civilization, settling part of what is now south western Iraq about 3,100 years BC

In 1660, Otto von Guericke built a device that could produce static electricity (there is also a school of thought that the ancients may have been able to produce what we would now think of as chemical batteries)

The first electric motor was invented by Faraday in 1821.

We have been sending radio signals int space for only the past 70 years or so.

Man first went to the moon 45 years ago and has not been back since 1972.

At the rate at which the human population is expanding and using up the earths resources, how long to you think we will survive as a species, 100, 500, 1000, 10,000 years or more than that?????

This then begs the question of how long does any technological species last on any planet any where in the universe?

Edited by reddoss
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Recent discoveries of Earth like planets in the habitable zone around stars show that they aren't all Jupiter like and too close to their star.

There could be plenty of life out there.

The problem is, that everything is so monstrously far apart we are very unlikely ever to make contact other than by perhaps monitoring their pollution levels by peering through our telescopes.

From what we know of the laws of Physics, it is just all too big, even if we could travel at near light speed.....and that is another monstrous 'if'.

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Life on earth exists due to a lucky set of circumstances and the correct chemical balances of various elements which enable carbon based life to generate.  There are only two possibilities:

Life exists elsewhere or life doesn't. 

Reddoss makes a superb point regarding timescales of life here on earth.  What if life elsewhere does exist but has been around for much longer because the circumstances allowed it?  Would it automatically dictate that this life must be intelligent?  I think not. If that asteroid had not been the catalyst for the extinction of the dinosaurs then earth could very probably still be inhabited by warm blooded lizards wandering about, unconcerned with this argument or the implications of it. 

I am not a theorist or a mathematician but as a reasonably intelligent individual I can suggest that the laws of probability must lend weight to the fact that if these random circumstances can allow life to exist here, then just like winning the lottery, it must surely have occurred somewhere else too.  If not in this galaxy then the next, or the next one after that.

I think it is fairly safe to suggest that there is life throughout the universe in some form or other - probably many, and made up of differing elements in a way that we cannot hope yet to fathom - maybe because carbon is unheard of and life has found another way? We will find it one day, perhaps in our own solar system.

The big question should be, what will it be like and where?  And when we do find it, what comes next?

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Whatever is out there.... don't worry.... it will be so distant as to be nonexistent for all purposes...... certainly as far as human life is concerned.

I would think all we need to worry about is some form of virulent microbe lurking in the Solar System somewhere.

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A perfect vacuum aside, it seems hard to prevent "life". Distinctly non-scientific, but I find it (conceptually?) quite hard to be reconciled with any LARGE, entirely sterile, environment - Even on today's Mars or Titan. Heck, I have to fight daily to keep "Extremophiles" out my own freezer...   ;)

Edited by Macavity
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Macavity's point has also occurred to me. Think of the poor souls charged with trying to keep hospitals safe for the sick!

Another anthropomorphic assumption, and one which stikes me as totally without foundation, is that technology and intelligence necessarily belong together. I see no reason whatever to believe this. We as a species have evolved to use technology because our environmental circumstances make it advantageous. This does not mean that the circumlstances pertaining elsewhere might make increasingly intelligent beings want or need technology.

Our environment is both varied and hostile. Merely by walking we can enter water and drown, climb mountains and asphyxiate ourselves, penetrate deserts and die from heat exhaustion or dehydration, or we can move too close to the poles and die of cold. We are also, partially carnivors who need to kill other, larger animals in order to eat them. We use technology to overcome these problems.

Would it be difficult to imagine an environment in which, while there was a pressure to evolve intelligence, there was no pressure to evolve technology? I don't think so. Male Peacocks have fancy tails because female peacocks prefer them. That may not strike us as much of a reason but it is sufficent reason. We could easily extrapolate to dream up a species whose intelligence was, if you like, purely decorative.

Olly

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The problem is that having a large brain is very costly, when you compare humans to other mammals we have a long gestation followed by a difficult birth at which point we are defenceless for years.

To evolve this way without the need to use that larger brain size to outsmart both predators and prey seems unlikely.

I would say that it may be more likely to evolve this way for a pressing survival need which then becomes redundant. For example the predators go extinct as they can't catch their prey anymore.

This could result in an intelligent species that doesn't actually utilise it's intelligence.

Sent from my iPhone using Tapatalk

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It looks as though there may be other obstacles to the development of intelligent life -

     

Red dwarf planets face hostile space weather within habitable zone

Red dwarfs comprise about 80 percent of the stars in the Universe, but their habitable zone—the distance from a star where liquid water may pool on the surface of the planet—is far more hostile than scientists have hoped.

Because red dwarfs are so dim and cool, a planet must exist in very close proximity to it in order to obtain adequate energy to harbor life. A planet would have to be much nearer than the Earth is to the Sun, nearer even than Mercury. This would subject it to extreme space weather due to the intense pressure of the stellar wind – a continuous flow of charged particles that is streaming from the star in all directions. The intense stellar wind at close distances is capable of stripping surrounding planets of their atmospheres.

Read more at: http://phys.org/news/2014-06-red-dwarf-planets-hostile-space.html#jCp

http://arxiv.org/pdf/1405.7707v1.pdf

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The selection pressures which drove the evolution of our intelligence are not the only selection pressures which might do so. We apply our intelligence externally through the use of technology. But can we conceive of a species who might, instead, learn to operate on their own internal biological structure from within? Instead of using technology to enhance their brain power they find ways of enhancing their brains from the inside.

I don't think that we should assume that hostility and competition need be the only evolutionary drivers, either. Remember that 'survival of the fittest' does NOT mean 'survival of the strongest.' It means 'suvival of the most appropriate.' Can we imagine environments, free of predators, in which intelligence might still be useful?

I don't see why not.

Olly

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The Eerie Silence was mentioned in an earlier comment by kerrylewis which covers most of this discussion as well as some interesting views on how any visitor might well not be biological but a mechanical/technological entity and also the chances that they are already here, just not observed. The search for non DNA/RNA like entities in our own planet (bottom of seas, high atmosphere) has not really been undertaken and if found would provide evidence that life has come about more than once on this planet, which would be significant from the point of view of disproving our complete uniqueness and give strong evidence that life is not an enormous fluke, but something that is all around and that as Olly says, is 'teeming' in our universe.

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I read a lot of talk about the "correct chemical balance". There are two points I would like to raise:

  1. The relative chemical abundancies of elements beyond helium (metals, in astronomy parlance) is fairly constant over vast tracts of space. The main changes is the total fraction of metals in the entire chemical make-up. Relative abundancies of metals have been measured in individual stars in M51 and more distant galaxies, and they suggest the chemical composition of stars there is similar to our galaxy.
  2. Life uses those chemical elements which are most abundant, because selection means those creatures using an abundant element (e.g. phosphorus) will thrive compared to those creatures that require a much rarer to do the same task (e.g. arsenic, which can replace phosphorus in many cases). We should not be surprised that our species thrives in the exact chemical surroundings we evolved in.

Maybe Douglas Adams was right, aliens avoid us because we play cricket ;)

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I have often wondered if life could exist in a completely different timescale, we can recognise life on earth because its lifespan is comparable to our own but what if it was a few micro seconds or millions of years it wouldnt register as life to us.

Alan

I would doubt it, not at least in the case of carbon chemistry I think, which would form complex molecules under a similar and same set of circumstances.

The kinetics ( the timescales/dynamics of chemical processes ) and thermodynamics of carbon chemistry are well understood. Chemical abundances aside of other elements, even if there was enough Silicon around for example,  I doubt any life form could be formed from any other elements, even with the same valency of carbon.  The special property that carbon can form complex chains is key to life formation as we know it, and the laws that govern carbon chemistry are the same wherever you go.

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And there was the key phrase, "life as we know it". Life doesn't have to fit into our narrow perception of what it should be.

Sent from my iPhone using Tapatalk

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Yes, first we need to define life. After you, Claude! It's a daunting task. We like to say that, while we are not sure how to define it, we know it when we see it. Well, we would say that. The point is, though, that our failure to see it doesn't mean it isn't there.

Olly

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[quote name="ollypenrice" post="2352360" timestamp="1402932717" our failure to see it doesn't mean it isn't there.

Olly

Too true, this applies to trying to find a DSO through a finder scope too ;)

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This thread really got me thinking. Here are some of my thoughts.

Is there life in our galaxy? Undoubtedly yes. There are just too many stars for there not to be.

Is there life in our solar system? Probably yes, but probably some simple form. Nothing that you could communicate with.

Will we ever communicate with another distant life form. No. The best we can hope for is capturing some transmissions from a distant planet and trying to make sense of it. Good luck with that one.

Would the life form want communicate with us? Now that's the interesting question. We count ourselves as intelligent and it happens that we have the physical characteristics that allow us to make stuff.

Now think of all the steps required to make a communications system. Making tools, making machines, making machines to make semiconductors, etc etc. Could a fish or rodent or what ever evolve to make that sort of thing?

We don't know because we were lucky enough to have the hands and intelligence. But given time, and there is a lot of it, could another life form develop to that extent. And is that really what intelligence is about.

DNA just wants to reproduce in whatever form. If a rodent evolved to communicate effectively enough that they could work together so as not to destroy themselves or the planet, would that be more intelligent?

In the long run technology amounts to nothing. It will be gone in no time at all after we are gone. The only measure of success is our ability to reproduce and survive.

I love technology. I love learning. But it is what we are doing with it that concerns me. It only takes one idiot with a misguided idea for it to go horribly wrong.

Make the most of your time here. Learn as much as you can and watch out for idiots!

cheers

gaj

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When humanity has run its course on Earth, as surely it will, the void will soon be filled. 

As the great biologist Jeff Goldblum once said: "Life finds a way". For a throw away line in a dinosaur movie it's quite a powerful idea. And one that I think is true.

Creating life from inanimate matter is the difficult bit. Once it's up and running, life is only held back by its environmental constraints.

Humanity is just such a constraint on the natural world. We're destroying our own habitat as well as that of most other species. When we're done there'll be a new explosion in strength and diversity. There'll be a lot of space to fill.

Mass extinctions are nothing new. Like wildfires, they're a necessary part of keeping a check on the environment. Perhaps the next dominant species won't be technological  nor even what we'd consider as being intelligent. These things aren't a requirement in evolutionary success.

Perhaps they are even dead ends or a fast track to self extinction??

The great white shark might agree..... if it could!!

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