Why do astronomers use earth climate metrics for debating the existence of life elsewhere?

I can't understand this. You often see astronomers claim such and such is "too hot" or "too cold" to sustain life, or that this mixture of gasses is inhospitable for life.

Says who?

I can't wrap my head around this notion. We've found life in the most inhopspitable places here on earth, yet it's impossible for life to develop in totally different kinds of ways elsewhere? We now have evidence to suggest the possibility of life on Titan, the clouds of Venus, and microbial life on Mars. How long before astronomers lose this notion that a planet must be Earthlike to support life? I understand they're merely basing it on what they "know" (i.e the fact we exist on an earthlike planet), but it seems utterly ignorant to assume life can't develop through other means elsewhere.

It all seems relative. What may be "too hot" or "too cold" for a humanlike species to evolve may not be for a species native to that climate.

If it is proven that some form of life exists on Titan and especially Venus, well, I feel my argument gains a lot of credibility.

I have thought that same bloody thing.

who says something cannot live in 100 degrees celcius heat.

or minus 100

just because we are pretty well adapted to Earth doesnt mean that is the standard for life, that nothing can exist outside these rules for life here.

I don't really see it as much as I used to, biologists and astronomers seem to be getting more open with their ideas of alien life.

I completely understand what you saying!
But you have to start from somewhere, and this Earth is all we know to start from. What I wonder is if extremofiles on other planets have evolved to be sentient beings, they could live to be millions of years old! wouldn't that be a sight to see! It would definitely make space traveling easier!


All hypothetical of course



source for my thoughts:en.wikipedia.org...

Originally posted by XxRagingxPandaxX
I completely understand what you saying!

But you have to start from somewhere, and this Earth is all we know to start from. What I wonder is if extremofiles on other planets have evolved to be sentient beings, they could live to be millions of years old! wouldn't that be a sight to see! It would definitely make space traveling easier!


All hypothetical of course

source for my thoughts:en.wikipedia.org...

I'm not aware of any extremophiles on this planet that are above the size of a microbe, but still, interesting thought nontheless.
I also think that it's possible for extremely long life spans, maybe not millions of years, but perhaps thousands or less, which increases the potential for space fairing aliens, as it's alot easier to do a 30 year trip to mars when you live for 1500 years.
Edit: Nevermind, apparantly there's quite a few extremophile multi cellular organisms, absolutely mind blowing.

[edit on 8-6-2010 by hippomchippo]

The chemical processes necessary for Biology, at least, Biology as We currently understand it, require certain environmental conditions in which to ocur.


If those conditions are absent, or too extreme, the chemical processes cannot ocur; ergo no biology, "life", in that environment would be possible.

By our standards.


But standards change, science learns, and life adapts well before we are bright enough to recognize it.

I too agree with you...
We were debating in class and I said: "How care if it's 300 degrees and there is no oxygen, we're human, another race don't necesserly needs this or is maybe adapted to this, like are birds fly, fishes swim, we are not the base of the world!"

It was among thoses lines and people in my class were like "well.." "yes but"..etc.
What we are saying is true, scientifics are basing their research on some stupid facts or lines that we need to base the search on human specifics...

I HATE that.

:\
Me mad!

Well some are saying that most the universe is filled with black matter or even cold black matter so maybe we can not see them.

it's stupid to think all life forms need to be based on anything like earth and air if i understand it was polution from the ion ore and we later developed to breath it but it generated a poison that kills us over time.

Maybe evolution means everything ends up being like computers and machines because thats likly to do better in space than we can do and do think before saying computers need us to build them because no one could build todays computers without using a computer for the design and production.

could be we ourselves are nothing more than memory in some type of nural network that has more states than simply on/off and dreaming is somehow connected and if that sounds silly then so does time going on 4 ever and distances that are never ending.

Computers are moving more towards using lights and crystals so we humans see things and remember which is just what you would exspect future memory to do but we are lucky and don't need to be refreshed 1000 times a second like Random Access Memoey (RAM) does and can count to more than one.

If thats too scientific then maybe we are some type of inter-galatic virius weapon sent across space to destroy worlds and i have quite a few good reasons to suport that theory once you realise a few millions years is the blink of an eye when you consider how old they say the universe is.

Like rats in a cage we don't have a clue do we.

[edit on 8-6-2010 by LieBuster]

reply to post by SaosinEngaged


becuase the most interesting kind of life is complex life. Higher plants , big animals & intelligent beings. No sign of those on titan, mars or venus. Its nasa astronomers thats brought you all that information on possible microbes in those extreme places. Microbes are fun but not as fun as complex life.

the holy grail of exoplanetary science is to find another earth with complex life. Becuase it would be possible for intelligent beings to evolve there, thats what everyone is looking for and to answer the question. Are we alone?

All scientists can do is look at data from other planets and determine if it is likely if life as we know it exists on other planets. How can we determine if a planet or moon can house life forms that are beyond our comprehension of what life is or could be, if we have zero understanding of these exotic life forms.

To give you an analogy, let us assume you and I go back in time a few hundred years. We go into a village and tell the people we have the ability to telepathically communicate to each other, but the villagers have no idea that we have walkie talkies.

The villagers are nevertheless incredulous of our claims. We tell them to lock us up in huts hundreds of feet apart. One person will go into one room and tell us a message. That person can then go into the other room where the other one of us is and hear the message. We are able to astound the villagers because we have walkie talkies.

From the villagers' point of view zero communication occured in our experiment. The villagers knew how to communicate by speaking, sending written messages, and by gestures or signals. The villagers assumed no communication occured because they could not see us speaking to eachother, sending written messages, or making any signals. It was outside the villagers' imagination to think we could send messages to eachother using electronic devices which send electromagnetic signals.

By analogy, scientists can only detect life by looking for what they can understand as life. Scientists understand life as being made of organic molecules like DNA and proteins. They understand life as being made up of cells. Just as the ancient villagers could not imagine walkie talkies, Scientists could not envision life that is not carbon based or not having any of the other characteristics scientists associate with life.

reply to post by yeti101


I totally get what you're saying, but without trying to be too speculative why does the assumption seem to be that only an earth like planet could sustain intelligent life?

Thinking logically, it would make sense that another earth like planet could possibly have evolved a species that is somewhat characteristically similar to us. But that, to me, does not preclude a totally "alien" (to us) species evolving under a different set of atmospheric and geologic conditions. There may not be complex life on Venus, Mars, and Titan because complex life still seems to be a relatively rare phenomenon. I would venture a guess that few, if any solar systems contain more than one intelligent species.

My ultimate point is that if I were in a position to be scanning for planets and predicting where to look for life, I wouldn't narrow my search solely to earth like planets. Really, any planet with an atmosphere could potentially harbor life.

And just so my beliefs are out there, I fully believe that our universe is teeming with life. I see no reason to subscribe to the rare earth hypothesis or any such skeptical view on extra terrestrial life.

The universe is such an enormous place, unfathomably so, that there may only be primitive life or pre electronic intelligent life in our neighboring starsystems.

Who knows? I know it's a movie, but the Na'Vi in Avatar are a good example of intelligent life that may exist that we'd likely never know about unless observed directly. It seems foolish to assume every intelligent species will have progressed as far as us or well beyond our capability.

It seems much more likely that at any given time, there are tons of primitive intelligent species, some that do not make it beyond our current level of technology due to the cataclysmic nature of the universe (impact events, climate shifts, etc), with only a select few possibly lasting hundreds of thousands to millions of years. And at that point, it would make sense that the species goes totally stellar and leaves terrestrial planets in favor of massive spaceships containing the entirety of their species.

The volatility of starsystems and even planets, to me, suggests that an ultra intelligent (very evolved) species would reside in space, not on a planet.

I could be way off, but these are just my (scattered and somewhat random) thoughts on E.T.

And this is a bit of a leap, but goes along with the last point I was making above:

Do you guys remember the Wow! signal? Or it might have been that one received in 2003, I don't have time to research it.

But I remember that either one or both of those was pinpointed to have originated from a "desolate" point in space with no known starsystems, which was one of the reasons it was dismissed as being possibility artificial in origin. Well what if that signal was sent from a space colony floating through the cosmos? Yes, again, it's a leap of faith, but thinking my point through logically, to me at least, it makes sense.

The point is, we don't know anything about extra terrestrial life. Nothing. Therefore we shouldn't be so quick to dismiss or make inferences on where life is or isn't possible to evolve.

We've been scanning the skies for what now, 40 years? At best? That's like a millisecond in astronomic timescales. Species probably evolve and die off in cycles, everywhere, much like how the dinosaurs went extinct before further evolution, unless they're evolved enough to reach the stars.

[edit on 9-6-2010 by SaosinEngaged]

you are partially right

I agree with you, that alien life exists in any type form place ...

but, we dont know any that exists on those places, actually, we do know, here on earth we find species living in some extreme places ... but

since the universe is so big, it is more easy to try to find life on planets like earth

and there are probably millions earths out there ...

reply to post by SaosinEngaged

ok wait. The only people looking for intelligent life are SETI they dont target individual planets they target stars. So its doesnt matter if their planet is like earth or not its what they can do that matters. (build radio or light beacons that we can detect)

when it comes to exoplanets the holy grail is to find another earth type planet. We only have 1 data point for life in the universe which is earth. The reason animals can be so big on earth is becuase they use oxygen which is very reactive and gives us all the energy and allows big animals and intelligent life to live.

The only way we know of that can replenish oxygen in an atmosphere of a planet is through photosynthesis ( plants, trees etc) & certain microbial life. If we find a planet thats a few billion years old and detect oxygen in the atmosphere it must be produced by plants or microbes. We can infer theres life there becuase of the presence of oxygen. If theres alot its probably produced by forrests/plants. If theres plants its likely theres complex animals and maybe intelligent beings.

tell me this. say we found a planet with an atmosphere like venus, how would we know life is there?


[edit on 9-6-2010 by yeti101]

I mentioned this in my seventh grade science class, and again in my sophomore biology class last year. Both times the other students, as well as the teachers but to a lesser degree, just kind of stared at me lol. IDK if they just didn't understand the concept, or if I wasn't explaining what I was thinking very well.
Either way they didn't grasp the idea that another planet's organisms might breathe methane and drink liquid nitrogen.

Another ATS thread mentioned a spring that is so salty it doesn't freeze, even though it is in subzero temperatures. I think it's in the area is called Lost Hammer. (or maybe that's the springs name) The extremophiles there live off sulfate I believe.
I thought that was interesting. Sorry if I got some of the facts wrong.

Thanks for the thread. I was hoping other people thought the same thing, and that I hadn't just overlooked evidence that showed Earth's conditions were the only suitable conditions.

As one member said,

WE NEED TO START FROM SOMEWHERE

And why not start with the only KNOWN habitable conditions, like that on Earth?

If we disregard known habitats, and completely open the playing field, you're going to spend less time looking at planets, and more time looking at stars, black holes, dark matter, ateroids, neutron stars, etc. for life.

We're putting all of our eggs in one basket, for simplicity and brevity.

One day, we will look farther, one day.

It's already known that some multi-cellular organisms don't need oxygen, they can live off of hydrogen, FYI.

[edit on 6/9/2010 by Schmidt1989]

[edit on 6/9/2010 by Schmidt1989]

reply to post by SaosinEngaged


I have thought about that aswel.

What we need to sustain life as we know it could be completley diferent elsewhere.

We may not even comprehend yet what types of other life exist elsewhere and what elements it needs or doesnt need.

'Life' could be completely diferent elsewhere. I suppose we are just trying to find life as we know it.

Let's also add that these same people believe that the periodic table of elements is also all of the elements in the universe. Why can't there be other elements in the universe that we don't have on this side of the galaxy and are on the other side, and these unknown elements are able to make a complex life form that is not carbon based.
Just food for thought

Originally posted by drwolf
Let's also add that these same people believe that the periodic table of elements is also all of the elements in the universe. Why can't there be other elements in the universe that we don't have on this side of the galaxy and are on the other side, and these unknown elements are able to make a complex life form that is not carbon based.
Just food for thought

Because we have a magical wand called a spectrometer.

reply to post by Schmidt1989

Has any one ever sent a spectrometer to the otherside of the universe, I don't think so.