Is life on other planets limited by the elements present?

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Discussion Overview

The discussion revolves around the possibility of extraterrestrial life, the characteristics of potentially habitable planets, the observable universe, and the concept of multiverses. Participants explore various hypotheses regarding the existence of life beyond Earth, the criteria for habitability, and the implications of universe expansion.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants express skepticism about the existence of life beyond Earth, suggesting that it remains speculative until evidence is found.
  • Several planets have been identified within the habitable zones of their stars, which could potentially support life as we know it.
  • There is uncertainty regarding the size of the universe, with claims that the observable universe is approximately 28 billion light years in diameter, while others argue it is around 46 billion light years due to cosmic expansion.
  • Some participants propose that the universe may not have boundaries and could be flat and open, leading to the possibility of a multiverse.
  • The question of how many habitable systems actually host life is raised, with acknowledgment that the probability of life emerging on Earth-like planets is unknown.
  • Concerns are voiced about the current search for extraterrestrial life being limited to Earth-like conditions, suggesting that life could exist in forms and environments vastly different from our own.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the existence of life beyond Earth or the specifics of the universe's size and structure. Multiple competing views are presented, particularly regarding the implications of cosmic expansion and the nature of potential extraterrestrial life.

Contextual Notes

Limitations include the speculative nature of discussions about life on other planets and the dependence on definitions of habitability. The mathematical and physical claims regarding the universe's size and expansion remain unresolved.

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Is it likely that there's life out there besides us?
Have we found any planets that COULD be capable of supporting life?
How much of the universe can we see?
Are there other universes?
 
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Your guess is as good as anyone's. Except maybe http://en.wikipedia.org/wiki/Drake_equation" . :smile:

We have found several planets that fall within the http://en.wikipedia.org/wiki/Habitable_zone" of their stars (supports liquid water). They could support life as we know it.

We are able to see an http://en.wikipedia.org/wiki/Observable_universe" approx. 28 billion light years in diameter. The universe is expected to be much larger than that - somewhere between 78 and 156 billion ly across.

There is much speculation about other universes, but we have no evidence, and no way for any evidence to be forthcoming in the forseeable future.
 
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Maybe in thousands of years when we live in a Star Wars universe
 
I don't think there are any other Universes. It could be just ours collapsing and being born again. When our Universe collapses completely it would become a point again, so the new Big Bang will happen. I only hope there are some slight differences between what happens inside of the Universe each time. That would be rather boring to live the same life all over again.

That depends on the nature of the "place" where the Universe was born. I don't think it could just pop out out of nothingness. Something must have happened at this particular space (I probably shouldn't call it this way).
 
Is it likely that there's life out there besides us?
Have we found any planets that COULD be capable of supporting life?
How much of the universe can we see?

1. No one knows. It's all speculation and guessing until it actually happens.
2. That COULD support life? Sure. One of Jupiters moons might be able to support life. Whether there is actually life there or not we will have to wait and see.
3. there's no telling how large our universe is. We are stuck with only being able to see our observable universe.
 
The observable universe is the only universe that is scientifically relevant.
 
1) There is no evidence of life out in the universe, but that does not mean that it does not exist.
2)The moon of Jupiter that you refer to is named Europa, where it is a guess that within the methane, life could exist.
3) Around 13 billion light years away ( furthest objects that we can see are quasers)
4)There is a theory of the multiverse. Where there could be a cycle of universes, continuesly expanding then shrinking (if dark matter = <1), but there could be lots of universes out there, all separated by more space, like stars in a galaxy, but universes in a multiverse
 
The visible Universe is not 13.7 billion light years across. This is because the Universe expanded in the course of it's evolution, we would be able to look that far, if the Universe did not expand (then it is just the light travel time from horizon to here, which is easy to calculate). The _radius_ (comoving distance to the horizon, now) of the observable Universe rather is 46 billion light years.

There is no known upper bound to the size of the Universe, as it may be flat and open, which means there is no boundary to the Universe.

It is very probable that there is life out there. We by now have found several planetary systems in the inhabitable zone, and that is only for the sun's nearest neighbours, so there must be a lot of them in the Universe as a whole. Also, wouldn't it be way too much of a coincidence to form exactly one such system? We have no yet found it though, and I am not saying we will. I am saying we won't get on contact, the distances are just too big...

There are several versions of Multiverse theories and they do not all have to do with the matter-energy density we live in.

Can I ask a question too: how in the world did such incredibly different questions end up in one post?
 
harcel said:
It is very probable that there is life out there. We by now have found several planetary systems in the inhabitable zone, and that is only for the sun's nearest neighbours, so there must be a lot of them in the Universe as a whole. Also, wouldn't it be way too much of a coincidence to form exactly one such system?

The question isn't how many habitable systems there are, the question is how many have life? We do not know the probability with which life will start on an Earth-like planet.

Also, there is the question of what level of sophistication we expect. Sure, we might find planets with bacteria and even lichen, but that's a looooong way from flatworms.
 
  • #10
harcel said:
The visible Universe is not 13.7 billion light years across. This is because the Universe expanded in the course of it's evolution, we would be able to look that far, if the Universe did not expand (then it is just the light travel time from horizon to here, which is easy to calculate). The _radius_ (comoving distance to the horizon, now) of the observable Universe rather is 46 billion light years.

There is no known upper bound to the size of the Universe, as it may be flat and open, which means there is no boundary to the Universe.

It is very probable that there is life out there. We by now have found several planetary systems in the inhabitable zone, and that is only for the sun's nearest neighbours, so there must be a lot of them in the Universe as a whole. Also, wouldn't it be way too much of a coincidence to form exactly one such system? We have no yet found it though, and I am not saying we will. I am saying we won't get on contact, the distances are just too big...

There are several versions of Multiverse theories and they do not all have to do with the matter-energy density we live in.

Can I ask a question too: how in the world did such incredibly different questions end up in one post?

But isn't it more likely that the visible Universe is around 13.7 billion light yeas across because the other theory you talked about said that the Universe didn't expand, yet, there's visible evidence that suggests it did in fact expand and is to this very day? Also, I agree that Universe probably has no boundaries, simply because we have no idea what those boundaries would be, right? But can the Universe really have a shape if it has no boundaries?

I also agree that the probability of other life is high although I think it'll will be very different to life on Earth. I don't think scientist are doing enough in searching for life because they're only really looking for planets like ours and if there is life other than our own, it might thrive off a totally different environment.
 
  • #11
But isn't it more likely that the visible Universe is around 13.7 billion light yeas across because the other theory you talked about said that the Universe didn't expand, yet, there's visible evidence that suggests it did in fact expand and is to this very day?

What exactly are you asking here? There's like a question here mixed with two statements. What did you mean by this?

Also, I agree that Universe probably has no boundaries, simply because we have no idea what those boundaries would be, right? But can the Universe really have a shape if it has no boundaries?

The boundaries could be anything from a physical wall to something else entirely. And the "shape" of the universe doesn't exactly equate to the physical shape. It's more like the shape of the acceleration.

I don't think scientist are doing enough in searching for life because they're only really looking for planets like ours and if there is life other than our own, it might thrive off a totally different environment.

The search for life is in it's infancy. The reason we look for planets like ours is because that is the only known form of life. It makes sense to start looking for life similar to our own. But also realize that the view on what it takes for life to form is changing all the time. We have discovered organisms that live in the crust of the Earth under the ocean that don't even require oxygen, and instead use Iron or something for respiration. Each new discovery expands our knowledge of life and expands our logical choices of places to look for life.
 
  • #12
Drakkith said:
The search for life is in it's infancy. The reason we look for planets like ours is because that is the only known form of life.
Also, there are some really excellent reasons why the most common life forms we encounter will very likely be much like what we get here on Earth.

You must remember, no matter how exotic a planet you dream up, it is still composed of the same <100 elements we have here, and in similar concentrations. And of those ~100, only a dozen or two do anything marginally complex. Of those dozen or two, the number that can form long complex molecules can be counted on one hand.

2] Hydrogen oxygen and carbon are very common and loooove to form reactive molecules.
3] Water is also very common and its special properties are myriad.
 

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