Alien life forms, do they exist?

[Rob060870]

Hello, I am interested to know how many readers think that we will find life in our solar system, if so when?. I am confident that we will find basic life forms in a human lifetime.

also if anyone thinks that there is more that one intelligent civilisation in our galaxy other than our own existing right now? I am not so sure on this one but hopefull, what do you think?

 

[mathman]

Definitely maybe to both questions!

 

[Chalnoth]

Definitely maybe to both questions!

I'll have to second that. Our knowledge is currently completely insufficient to say how common life is. So yeah, maybe.

As far as when, I suspect it will be fifty to a hundred years or more before we're able to conclusively rule out life in our solar system. Discovery of life could happen any time, if it's there.

Life elsewhere in the galaxy will be vastly harder to pinpoint. We may be able to detect planets that could support life within a decade or so, but actually verifying that it's out there is going to be massively difficult.

 

[Gaius Baltar]

In my opinion... Yes.

 

[Vagn]

I'd have to agree with the definitely maybe, I'd say the likelihood of discovering life elsewhere in the solar system is quite likely, but whether this evolved independantly from Earth based life is a different question, as it may be possible that a meteorite from Earth contaminated the other body.

Again, their could be more intelligent life in our galaxy, but we might not necessarily discover it, due to the vast distances involved, or we could simply be the most advanced species in the galaxy, someone has to be. Personally I think there probably is intelligent life in the galaxy, although again we might not ever make contact, and I'd say that it is rather egotistical to dismiss the possibility out of hand (and would also go against the Copernican Revolution, that the Earth and our Solar System is not unique).

 

[Chalnoth]

I'd have to agree with the definitely maybe, I'd say the likelihood of discovering life elsewhere in the solar system is quite likely, but whether this evolved independantly from Earth based life is a different question, as it may be possible that a meteorite from Earth contaminated the other body.

"Quite likely" is pretty strong for life within our solar system. Compared to the Earth, everywhere else is extremely inhospitable to life as we know it, and it is currently rather speculative whether life based upon other chemical structures is even possible.

That said, Europa probably offers the best chance for life elsewhere in the solar system, followed by Mars in second.

 

[Vagn]

"Quite likely" is pretty strong for life within our solar system. Compared to the Earth, everywhere else is extremely inhospitable to life as we know it, and it is currently rather speculative whether life based upon other chemical structures is even possible.

That said, Europa probably offers the best chance for life elsewhere in the solar system, followed by Mars in second.

True, I was more referring to the possibility of finding bacterial spores or dormant bacteria which originated from the Earth on some other body, but I suppose you could argue whether these are alive or not anyway.

 

[Chronos]

Find liquid water and you definitely maybe will find some form of life. Liquid water is known to exist on moons of the gas giants and probably mars. Give me an ocean with undersea volcanic vents -.

 

[Rob060870]

There is growing evidence that an ocean of liquid water lies beneath the surface of Jupiter's moon Europa. But looking for life in that ocean requires getting under an icy crust perhaps several kilometers thick.
I have heard that NASA plan to melt through the thick ice and then a submarine-like hydrobot will explore this underground ocean sending a live feed back to us!.
I think that this sort of mission is very exciting indeed.
also in a few years we will be able to analyze the atmosphere on other planets around different star systems, how interesting would it be if we found a planet in the goldilocks zone use spectral analasis and found cfc's or organic compounds even oxygen in the atmosphire!.

 

[Chalnoth]

There is growing evidence that an ocean of liquid water lies beneath the surface of Jupiter's moon Europa. But looking for life in that ocean requires getting under an icy crust perhaps several kilometers thick.
I have heard that NASA plan to melt through the thick ice and then a submarine-like hydrobot will explore this underground ocean sending a live feed back to us!.
I think that this sort of mission is very exciting indeed.

Well, not any time soon, that's for sure. This sort of mission would be massively, massively difficult. Consider, for a moment, what is required:
1. Power source that can melt through that much ice. This should actually be the easiest part, as all you'd need is a sufficient quantity of radioactive material. But it would need to be quite a bit more substantial than previous space-borne nuclear power sources.
2. It's not possible for the probe to communicate with the surface via radio waves, so we'd probably need some sort of cable connecting it to the surface. Since the water will quickly re-freeze as the probe passes, the cable would need to be unspooled from the probe as it sinks. If the ice is kilometers thick, this would require a kilometers-long cable! The cable, of course, will have to actually survive the descent of the probe, and remain in tact for the entire mission.
3. At a depth of several kilometers, the probe itself is going to have to deal with massive pressures. As with #1, this should be relatively easy to solve. It just hasn't been done before on this scale in space.

The biggest problem, I think, will be communicating with the surface. If the ice is actually kilometers thick, it may simply not be doable in this fashion. Our best bet might be an autonomous probe that sinks into the ice, goes through a pre-programmed routine, then ascends back to the surface through the use of some sort of ballast. Upon reaching the surface, it may communicate again, probably with a satellite set in orbit around Europa.

In any case, this sounds to me like an absolutely massive, though fascinating mission. I do hope we do something to observe the oceans under Europa's ice, but I'm suspecting it may be quite a while.

Looks like the currently-planned mission for Europa is an orbiter, and the sort of information we might glean about the ice from an orbiter may help tremendously in planning for a more ambitious mission under the ice.

 

[jreelawg]

I think that if we drill we will find life underground in Mars. I think there is even likely life underground in Venus.

 

[Chalnoth]

I think that if we drill we will find life underground in Mars. I think there is even likely life underground in Venus.

While there is some possibility of life underground on Mars, there is very little possibility of it on Venus. The problem with Venus is that it's too hot, and the temperature too uniform. The temperature is far too high for any sort of complex chemistry to go on, and even if there happened to be organisms that could survive in such extreme temperatures, there are no differences in temperature near the surface for organisms to take advantage of (life thrives on heat transfers from one system to another...it must make use of such heat transfers in order to survive).

 

[DaveC426913]

The biggest problem, I think, will be communicating with the surface.

Easy solution to eliminate probe-cable or probe ascent to surface:

uponLanding(){
  turnUpReactorTemp([B]iceMelt[/B]);
  if (testForLife() == true){
     turnUpReactorTemp([B]explode[/B]);
  }
}

Earth based telescopes take it from there...

 

[Rob060870]

I believe that life in the Universe is common( it would be interesting if simple life forms were found in our solar system then I would love to know if its DNA like code was similar to ours). however Intelligent life. . . now that's a different matter!. it does appear to be very rare indeed if SETI is anything to go by.
if an advanced Civilisation exists then how long would its life span be?

 

[Sniperman724]

We really can't be the ONLY intelligent life in the universe too, there are trillions of stars, each with their own solar system filled with planets. I really think there's some form of intelligent life somewhere in the universe.

 

[DaveC426913]

We really can't be the ONLY intelligent life in the universe too, there are trillions of stars, each with their own solar system filled with planets. I really think there's some form of intelligent life somewhere in the universe.

Isn't that kind of like saying 'there's two hundred million square miles on planet Earth, surely Everest can't be the ONLY 29,000foot tall mountain'?

 

[Physics-Learner]

are we "intelligent" life forms ? LOL.

 

[Eyelegal]

I think with the recent discoveries of so many extrasolar planets, its almost not a question we need to ask anymore. In my opinion there are likely to be at least a couple other planets with life forms, if not civilisations, within about 200ly of us. Evidence is pointing to places being fit for life to exist being pretty common, estimates as high as 10% of stars having planets in habitable zones? The real problem in my opinion isn't having the planets, its having the right elements and molecules developing organic chemistry. With the discovery of other organic things simply floating in a soup like this = http://www.tgdaily.com/space-features/48724-organic-molecules-discovered-in-orion-nebula" it really gives me the impression that us being alone is VERY unlikely. Have they flown here in rotating discs though? Probably not.

 

[Chalnoth]

I think with the recent discoveries of so many extrasolar planets, its almost not a question we need to ask anymore. In my opinion there are likely to be at least a couple other planets with life forms, if not civilisations, within about 200ly of us. Evidence is pointing to places being fit for life to exist being pretty common, estimates as high as 10% of stars having planets in habitable zones? The real problem in my opinion isn't having the planets, its having the right elements and molecules developing organic chemistry. With the discovery of other organic things simply floating in a soup like this = http://www.tgdaily.com/space-features/48724-organic-molecules-discovered-in-orion-nebula" it really gives me the impression that us being alone is VERY unlikely. Have they flown here in rotating discs though? Probably not.

Even with the most optimistic probability estimates, a civilization 200 light years from us is horrifyingly unlikely.

The real problem, however, is twofold:
1. We don't know how common the right conditions for life are.
2. Given the right conditions for life, we don't know how common life actually forming is.

It doesn't help that we know even less about the probability of the formation of a civlization.

 

[Eyelegal]

Well then you start asking the brain question, is the development of the brain into a thinking and reasoning tool a common occurrence or simply luck that exist once in a thousand galaxys. You can be pessimistic about intelligence, but if the data being returned by planet finding missions like kepler and at the keck telescope are anything to go by, habitable zone planets are far more common than we thought, and now they have found organic compounds in star forming nebula? What more evidence do we need to deduce that life is probably fairly common? Intelligence might be a big stretch, but i don't think organisms are at all, and that's where it all has to start.

 

[Eyelegal]

Isn't that kind of like saying 'there's two hundred million square miles on planet Earth, surely Everest can't be the ONLY 29,000foot tall mountain'?

No, its not...because we know Everest is the tallest mountain as a fact. We don't know the amount of stars in the milky way or the probabilities of habitable planets as a fact. Kind of a terrible analogy...

 

[DaveC426913]

No, its not...because we know Everest is the tallest mountain as a fact. We don't know the amount of stars in the milky way or the probabilities of habitable planets as a fact. Kind of a terrible analogy...

I did not define Everest as the tallest mountain, I simply chose a parameter for mountains of interest: higher than 29,000 feet.

That there are uncountable thousands of mountains is not, in and of itself, a reason for there to be more than one matching a given set of parameters.

 

[Eyelegal]

You defined 29000 feet, the only mountain which fits that description on Earth is everest. We know that as a fact? I thought things that we knew as truths actually exist? Your analogy didnt make sense because we have mapped earth, we know how high mountains are. We have not mapped the galaxy, so we do not know the amount of stars and planets, so we can only make guesses educated by the current level of knowledge about our galaxy. If its about chance...the chance of everest being the only mountain higher than 29000 feet on Earth is 100% isn't it?

I see where you are coming from, in that there is no proof that stars other than our own should have life around them. But, arent we beginning to get proof which allows us to make observations like Snipermans? Hasnt the probability of other life gone up hugely?

 

[Physics-Learner]

does everyone think that intelligent life needs to be carbon and water based, with a chemistry similar to our own ?

 

[Chalnoth]

does everyone think that intelligent life needs to be carbon and water based, with a chemistry similar to our own ?

No. There are other proposals. But we don't know if any of them are viable at present.

 

[Eyelegal]

does everyone think that intelligent life needs to be carbon and water based, with a chemistry similar to our own ?

http://en.wikipedia.org/wiki/Hypothetical_types_of_biochemistry"

This is a fairly good list of different chemistry types that could exist. I think our deal here is the most stable one possible?

 

[Oldfart]

We seem to be interested in looking "outside" for alien lifeforms, but why not look here first? Here right on Earth we Have ideal conditions, and a variety of such conditions, for a different form of life to develop. Are we actively looking for it?

Along this line, I think that if some form of "alien" life cannot be found here despite an extensive search, the likelihood of finding it elsewhere is sharply reduced.

OF

 

[Eyelegal]

We seem to be interested in looking "outside" for alien lifeforms, but why not look here first? Here right on Earth we Have ideal conditions, and a variety of such conditions, for a different form of life to develop. Are we actively looking for it?

Along this line, I think that if some form of "alien" life cannot be found here despite an extensive search, the likelihood of finding it elsewhere is sharply reduced.

OF

Alien life is life that didnt develop here...unless you mean life that is alien to us. In that case do you mean the tube worms that live next to black smokers spewing superheated water deep in ocean trenches where we would expect water pressure and heat to kill all life forms?

Perhaps the organisms that live in hundred degree geothermal pools full of sulphur?

There are many "alien" creatures you can find on earth. If that's what you mean.

If you mean actual alien life...im really not sure what your talking about. How alien life would get here unassisted is...alien to me.

 

[Oldfart]

Well, what I mean by "alien" is not life from somewhere else, but life which is different from the carbon based life that we are acquainted with at present here on Earth.

OF

 

[Eyelegal]

http://en.wikipedia.org/wiki/Diatom"

Is the only one I could find quickly, an example of partial silicon biochemistry...sort of.

The problem with silicon is that it exists in far greater numbers than carbon on earth, yet carbon developed as the basis for life on Earth, suggesting that silicon life is hard to develop.

The problem with any other organic chemistry is that, to our current knowledge, all of the possibilities just don't stack up with a great chance of success. Organic chemistry with carbon is simply the most stable and easy to produce. Its probable that if life exists elsewhere, it too is mostly composed of carbon, with the probable exception of a certain % of planets/moons with life.

http://en.wikipedia.org/wiki/Carbon#Organic_compounds"