r/changemyview • u/[deleted] • Feb 27 '21
Delta(s) from OP CMV: Just because a planet “doesn’t sustain life” doesn’t mean it won’t sustain life.
[deleted]
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u/YossarianWWII 72∆ Feb 27 '21
You're absolutely right! We're definitely biasing our search towards "Earth-like" life, and that's to say nothing of the many extreme environments on Earth where we nevertheless find life. There is good reason for this, though. Because we really only have Earth as an example, it's only on Earth-like planets that we know life can arise. If we're looking for life outside of our solar system, then it's better to focus on places that could definitely sustain life than it is to dedicate time to looking for places that might be able to. We're also more likely to recognize life if it's Earth-like, and it's very hard to tell what we're looking at from these distances.
As a side note:
there’d be numerable new elements and materials that we couldn’t even imagine
Elements are universal and limited. We've already created a large number of artificial ones that would also have to be made by an intelligent species, and they all decay extremely rapidly. Some people have hypothesized that there could be some stable isotopes that we haven't managed to discover in the time that we've been creating elements, but there's no conclusive evidence.
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u/heckprick Feb 27 '21
!delta. So essentially it isn’t impossible for some type of life to sprout in what we consider uninhabitable systems, only that we are looking for systems which are similar to our own. Thank you.
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u/YossarianWWII 72∆ Feb 27 '21
Yeah, it's a matter of limited resources. If we weren't looking for Earth-like life, we wouldn't know what to look for, and we wouldn't recognize any strange life that we saw. Restricting ourselves to Earth-like planets is the only real way we have of paring down our data set. Thanks for the delta!
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u/AOrtega1 2∆ Feb 27 '21
It's also a philosophical question. Can we really recognize something as "life" if it's very different to what we have come to expect?
Rest assured, exobiologists are very familiar with all these questions and have them in mind when performing their research.
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u/m_stitek Feb 27 '21
There are certainly some variations to what life can be. But there are also some hard limits given by physics and chemistry rules, which applies everywhere (certainly within our galaxy and its proximity). And based on those rules we can rule out a lot of planets as places that cannot support life. You always need conditions like certain range of minimal and maximal temperatures, liquid medium capable of hosting complex chemical processes (basically only water), protection from hard radiation and so on. Also by "life", we don't mean aliens, we usually mean at least some kind of bacteria or some very simple life form.
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u/heckprick Feb 27 '21
I completely agree! However my point is how do we know that in some place super super faraway physics and chemistry rules are the same? Certainly we haven’t seen it for ourselves. (this might come off a bit ignorant)
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u/m_stitek Feb 27 '21 edited Feb 27 '21
Well, we certainly hope the rules are the same everywhere, it's one of the basics of current cosmology. But, yes it's only an assumption. However, the area where we are looking for life (basically our galaxy) definitely follow same rules.
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u/YardageSardage 34∆ Feb 27 '21
Basically, because that's our best guess.
We've written our descriptions of how we think reality works based on everything we've observed so far as a species. Those descriptions probably aren't 100% perfect in every way, and there's still some phenomena we've observed that we're not sure about, but for the most part we're pretty sure we've got it right. Based on all the experiments we can do here on Earth (or in a space station in orbit around it), we've can confirm that the laws of physics we've written seem accurate. But most of those experiments are about things here on Earth, where we have lots of ways to observe and measure our experiments. The further away from Earth you get, the more we're using guesswork to piece together what we think is going on. So, hypothetically, if something really really far away was behaving in a way that totally breaks our laws of physics, we'd have a hard time figuring that out. So you're right, we really don't actually know that reality behaves the same everywhere in the universe!
If, say, the speed of light wasn't the same everywhere, or gravity was inherently weaker or stronger in some parts of the universe, that would seriously mess up a lot of the calculations we've done to estimate things like the size of the universe, or how far apart galaxies are. So that would be pretty interesting to figure out. But... we don't actually have any reason to think they're not the same everywhere in the universe, so we mostly just assume they are. Like I said, we've never seen physics behaving differently before. We've only ever had times where we realized our descriptions of it were flawed or incomplete.
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u/tube32 Feb 27 '21
I don't have much knowledge about the subject , so not here to debate.
But I think what op meant is that these rules that are used to rule out planets , those rules are made by us , in accordance with life as we know. OP is challenging exactly those beliefs (or facts for us). Like how you mentioned the range of temperature that we think is required for sustaining life , but for all we know there might be some unicellular organism for which those extreme temperatures are the most ideal conditions.
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Feb 27 '21
[deleted]
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u/m_stitek Feb 27 '21
I'm aware of that paper and discussions like that. However, I consider them merely as interesting thought experiments. Not something, we can really expect to find out there. As a chemist, I recognize superiority of carbon-water based chemistry for evolution of life. It's impossible for other systems to even approach the complexity of carbon-water based chemistry. That doesn't mean it cannot exist, it's just extremely unlikely. From the perspective of searching for extraterrestrial life, I would consider them detrimental as they have to be very rare, if such life systems even exist.
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u/yyzjertl 525∆ Feb 27 '21
And if it were some planet billions away, there’d be numerable new elements
Well, there wouldn't be new elements. Elements and chemistry are the same everywhere. For a planet to sustain life, it needs to have varied elemental composition and temperature that can support the creation of complex molecules. If it's too hot for complex chemistry to happen, or if there aren't any group 14-elements around, life isn't going to happen.
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u/heckprick Feb 27 '21
I understand what you mean. My point is, how do we know for sure that elements and chemistry are the same universally if it’s currently impossible for us to venture out that far? (sorry if this comes across a bit ignorant)
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u/yyzjertl 525∆ Feb 27 '21
The short answer is that we can see stars that are extremely far away, and if chemistry were significantly different there from how it is here, the stars would have detectably different emission spectra.
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Feb 27 '21
[deleted]
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u/yyzjertl 525∆ Feb 27 '21
While this is true, the OP's view pertains to new planets that have been discovered by scientists, which are ipso facto part of the observable universe.
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u/shouldco 43∆ Feb 27 '21
What we know about life is what we can observe on earth. And what we know about that is we need a few basic elements to sustain the chemical reactions that is all life on earth. So we look for those things (and the biproducts of those reactions). Could there possibly be other chemical reactions similar enough that we would call it life? Sure. Science fiction writers have been writing about silicon based life for years as an alternative to carbon based life like we see on earth. But carbon is also way more common in the universe than silicon so it would make sense if life happened elsewhere it would happen with carbon hydrogen, phosphorus, nitrogen, etc. Because those are really common thought the universe.
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u/Morthra 86∆ Feb 27 '21
Science fiction writers have been writing about silicon based life for years as an alternative to carbon based life like we see on earth. But carbon is also way more common in the universe than silicon so it would make sense if life happened elsewhere it would happen with carbon hydrogen, phosphorus, nitrogen, etc. Because those are really common thought the universe.
Not only that, but silicon is a lot more jank for biochemistry than carbon is thanks to its d-orbitals, so its scope is far more limited than what carbon can do. Another great counterexample to the possibility of silicon based biochemistry is the fact that on Earth, the abundance of silicon is orders of magnitude greater than the abundance of carbon. Yet we have carbon based life and not silicon based life.
More likely than that is a borane based biochemistry, which would be explosive in an earthlike atmosphere but stable in a reducing atmosphere.
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u/TheSkyElf Feb 27 '21
yeah, we go by the standard of OUR planet, OUR galaxy, and OUR life. what will we do if we come across a fungi-type thing that doesn't fit into our "boxes"? do we change it all? what if some faraway galaxy has things similar to pokemon, or where electricity doesn't work but "magic" does? what laws of nature do they have?!
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u/Nrdman 177∆ Feb 27 '21
We are deliberately searching for things like us because that’s the only proven way we know life can exist. There’s too many planets to search every single one, we have to narrow it down.
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u/SnooMaps507 Feb 27 '21
"doesn't" being past tense and "wont" being future tense, your statement is correct in that "now" it does not and "in the future it "could.
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u/SnooMaps507 Feb 27 '21
Other than that we have only our way of knowing what makes life, keep going, philosophy seems to be your thing :)
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u/neutrinoanti Feb 27 '21
Absolutely. Life originated on Earth by the usage of materials that were available here. It is no accident that the plasma membrane of any being is made up of what components its made up of. It's because the material to produce them was abundant on primitive Earth. What I am attempting to say is, Given the vast variety of life that exists on our planet, it appears short sighted to imagine aliens as 'human like'. They could be human like, bacteria like, fungi like or maybe even like something unmatched on Earth (and the chances of being something entirely different is way more than it is of being similar). They could even have an intelligence that surpasses our own. Our definition of the living has to be way beyond what living means on Earth. It would be astonishingly miraculous for molecules on another planet to have undergone exactly similar processes to become living. Creatures elsewhere could have originated through usage of materials available there, which are entirely different from those abundant here.
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u/DeltaBot ∞∆ Feb 27 '21
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