New Study Dramatically Narrows the Search for Advanced Life in the Universe:
In a new study, a UC Riverside–led team discovered that a buildup of toxic gases in the atmospheres of most planets makes them unfit for complex life as we know it.
Traditionally, much of the search for extraterrestrial life has focused on what scientists call the "habitable zone," defined as the range of distances from a star warm enough that liquid water could exist on a planet's surface. That description works for basic, single-celled microbes—but not for complex creatures like animals, which include everything from simple sponges to humans.
The team's work, published today in The Astrophysical Journal, shows that accounting for predicted levels of certain toxic gases narrows the safe zone for complex life by at least half—and in some instances eliminates it altogether.
"This is the first time the physiological limits of life on Earth have been considered to predict the distribution of complex life elsewhere in the universe," said Timothy Lyons, one of the study's co-authors, a distinguished professor of biogeochemistry in UCR's Department of Earth and Planetary Sciences, and director of the Alternative Earths Astrobiology Center, which sponsored the project.
"Imagine a 'habitable zone for complex life' defined as a safe zone where it would be plausible to support rich ecosystems like we find on Earth today," Lyons explained. "Our results indicate that complex ecosystems like ours cannot exist in most regions of the habitable zone as traditionally defined."
[...] "To sustain liquid water at the outer edge of the conventional habitable zone, a planet would need tens of thousands of times more carbon dioxide than Earth has today," said Edward Schwieterman, the study's lead author and a NASA Postdoctoral Program fellow working with Lyons. "That's far beyond the levels known to be toxic to human and animal life on Earth."
Similar difficulties occur with respect to ultraviolet light which leads to excess carbon monoxide; even small amounts preferentially bind to hemoglobin leading to "death of body cells due to lack of oxygen."
More information: Edward W. Schwieterman et al. A Limited Habitable Zone for Complex Life, The Astrophysical Journal (2019). DOI: 10.3847/1538-4357/ab1d52
No word on what parameters would apply to the planet Vulcan.
(Score: 5, Insightful) by Snow on Wednesday June 12 2019, @07:11PM (18 children)
We have ONE example of life on a planet. Who knows what other shapes life can take? We know nothing.
(Score: 2) by Runaway1956 on Wednesday June 12 2019, @07:21PM (7 children)
Exactly.
If/when we do meet intelligent life, we may very well learn that our life isn't very complex at all. Speaking of complexity - imagine if it took three or more genders to procreate? Getting some would be a real bitch!
(Score: 3, Interesting) by JoeMerchant on Wednesday June 12 2019, @07:32PM (5 children)
Here's the real kicker: complex life may be observing us right now, and even plainly visible or otherwise detectable to us, we just don't recognize it because it hasn't tried to plant a flag and trade beads with us, yet.
🌻🌻 [google.com]
(Score: 4, Insightful) by fyngyrz on Wednesday June 12 2019, @07:43PM (2 children)
If life is observing us locally, the implication is it got here from somewhere else, inasmuch as we haven't seen any elsewhere in our solar system.
That being the case, considering the level of technology they'd have to have to pull that off, I'm not sure we'd have any beads they might want.
Pomegranates, perhaps. :)
--
You come from dust. You return to dust. That's
why I don't dust. Might have been a friend.
(Score: 4, Interesting) by JoeMerchant on Wednesday June 12 2019, @08:05PM (1 child)
I like the Niven theory of interstellar traveling hydrogen gas plasma beings - they've had billions of years more than us to evolve, they'd be big, diffuse, low energy phenomena, and they've likely long since learned how to deal with pond scum like us. If there are any tricks to FTL/interdimensional travel, again, they've had billions of years more than us to find them. They could well be observing us through a barely detectable space-time window, hiding the bulk of their bodies light years away. Lite beer and bluejeans probably don't interest them.
🌻🌻 [google.com]
(Score: 0) by Anonymous Coward on Friday June 14 2019, @08:25AM
Maybe the bulk of life is self-reproducing and evolving patterns in stellar plasmas?
Or even most life is in the >90% dark matter/energy of our universe and we're both insignificant and rare stuff depending on your perspective?
(Score: 1, Interesting) by Anonymous Coward on Wednesday June 12 2019, @10:37PM (1 child)
The *SUN* is an advanced form of life, and solar flares, gravity, etc are its ways of interactive with the universe around it. How do we know that solar activity is not in fact the Sun trying to communicate with other suns, or even in some cases with life on Earth?
There are many possible forms of evolution, and many of them might not interact with the universe, matter, or each other in ways that we would understand, acknowledge, or even have the individual lifespan to observe and communicate with. The wrong two species, one with an extremely long interval of life and slow responses, and one with an extremely short interval of life and fast responses might not even be able to see, remember, or interact with each other due to their varying frames of time, and states of mind.
(Score: 2) by arslan on Thursday June 13 2019, @01:13AM
Yea.. we're all just gnats on a living planet. Jupiter's coughing up a fit and Mars is dusting off its dandruff right now but we're just too non-complex to understand it.
(Score: 0) by Anonymous Coward on Wednesday June 12 2019, @07:53PM
Possibly, unless they're space bonobos [wikipedia.org].
(Score: 3, Interesting) by fyngyrz on Wednesday June 12 2019, @07:40PM (1 child)
Exactly this. I laugh every time I see something like this... and I've seen many such unreasonably blinkered examples of it, too.
We simply can't look at life on Earth and assume that is the only way life can arise. It's a way. That's all.
When (if) they qualify with "earth-like life" then they have a (mildly) interesting observation. But life in general? Nah. Meaningless. Plus, its entirely possible that earth-like life has established some kind of habitat-away-from-home in an otherwise non-earth-like environment, because reasons. Resources, science, greeting / embassy to the local [insert metabolism here] life forms, whatever. And should we be only looking for earth-like life? Of course not. That would be stupid. So. Pbbbbt.
--
If you are experiencing joint pain, you probably
shouldn't be holding the lit end.
(Score: 3, Insightful) by Hartree on Thursday June 13 2019, @03:29AM
Heck, we can't even give all that great a definition for "life". We've got some general rules in biology classes but it only really fits for the kinds of life we've seen.
It's a bit like that old saw about pornography: "I can't define it but I know it when I see it."
On the other hand, I'm not at all convinced that we would immediately know some kinds of life if we saw it. How about a rocklike being not based on the usual earth chemistry that has a childhood lasting half a million years? We'd have sawed it up and made jewelry out of it without knowing unless we figured it out from the fossil record and even that would be pretty subtle to pick out of normal geology.
(Score: 3, Interesting) by NotSanguine on Wednesday June 12 2019, @07:51PM
A fair point. And I'm not convinced that the reasoning (at least in the headline/TFS) is warranted, given the ability of life "as we know it" to thrive in extreme environments. Who's to say that such life couldn't develop and thrive in even more extreme environments, given enough time, mutations and natural selection?
While it's certainly plausible that life (even complex life) doesn't require organic chemistry [wikipedia.org], we *know* (from that one example) that life *can* arise from it.
What's more, carbon is not only one of the most abundant elements in the universe, but it's also hypothesized that something like 20% of carbon in the universe [wikipedia.org] is in the form of complex carbon compounds [wikipedia.org].
While there are an array of other elements upon which complex life could be synthesized (with complex crystalline structures rather than carbon compounds, for example), we have no way to detect the presence or byproducts of such life.
We have at least a clue as to what to look for with carbon-based life, or at least carbon-based life that uses/generates molecular oxygen. As such, even with our extremely limited (not nothing) knowledge, we might as well go with what we do know.
Is it possible that we'll overlook life "as we don't know it?" Absolutely. Is it possible that other forms of complex life are far more abundant in the cosmos than the form we have here? Sure.
All that said, the *known* abundance of elemental carbon, and the hypothesized abundance of complex organic molecules "out there" gives the development of carbon-based life an edge over life based on other, less abundant elements, IMHO.
No, no, you're not thinking; you're just being logical. --Niels Bohr
(Score: 2) by HiThere on Wednesday June 12 2019, @07:59PM (1 child)
Yes, and in that one example the atmosphere was not suitable of the existence of complex life before simple life evolved.
We *live* in an atmosphere composed of microbial anti-bacterials. Oxygen, for one example.
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 2) by maxwell demon on Wednesday June 12 2019, @11:52PM
Moreover, our current atmosphere would be highly toxic for those early life forms.
The Tao of math: The numbers you can count are not the real numbers.
(Score: 2) by edIII on Wednesday June 12 2019, @08:08PM
Actually, we know more than nothing. There are many different types of life on this planet. In some places, it's not based on breathing oxygen at all, nor does it require sunlight. We have different classes of extremophiles on this planet.
We continue to find life in our own backyard in places that 99% of the life on our planet cannot exist, and we presumed no life could exist. So we kinda know better and shouldn't presume that a form of life couldn't exist in the presence of that much CO2.
Technically, lunchtime is at any moment. It's just a wave function.
(Score: 0) by Anonymous Coward on Wednesday June 12 2019, @09:15PM
For each and every "toxic gas", there is a lifeform or many, right here on planet Earth, that are fully immune to it. Shame to the "peer reviewers" that allowed this waste of bytes also become a waste of paper.
(Score: 3, Insightful) by takyon on Wednesday June 12 2019, @10:12PM (1 child)
Maybe we should just use "human-habitable" so that this nitpick isn't trotted out every time.
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 2) by arslan on Thursday June 13 2019, @01:15AM
but but... that would stop jokes like Uranus is actually mooning us right now, we're just too simple to understand it.
(Score: 0) by Anonymous Coward on Thursday June 13 2019, @12:21PM
Exactly. Looking for conditions that created humans on other planets is a good idea if you're looking for humans...
The actual fuckers roaming the void might not even be carbon based. Hell they might even be some mystic swirls of pure energy.
Shame on these UCR 'scientists' for their very myopic approach.
(Score: 1, Insightful) by Anonymous Coward on Wednesday June 12 2019, @07:46PM (1 child)
"To sustain liquid water at the outer edge of the conventional habitable zone, a planet would need tens of thousands of times more carbon dioxide than Earth has today,"
Soon the Earth will be ready for its move to the outer edge of the habitable zone.
(Score: 2) by PartTimeZombie on Wednesday June 12 2019, @10:44PM
Oh great! So now we all have to get out and push?
Stupid planet doesn't even work properly. We should get a new one.
(Score: 1, Funny) by Anonymous Coward on Wednesday June 12 2019, @07:55PM (5 children)
I'm...
an...
ent,...
you...
insensitive...
clod!...
I...
breathe...
CO2!
(Score: 2) by HiThere on Wednesday June 12 2019, @08:03PM (4 children)
The problem is that CO2 is a strong greenhouse gas, so if there's too much the seas will boil. Being an Ent wouldn't help you survive that.
But it's quite possible that microbes living in the upper atmosphere (high enough so water condenses) could over time metabolize that CO2. This has actually been proposed for Venus, but I think it's too close to the sun for a good result.
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 3, Insightful) by ElizabethGreene on Wednesday June 12 2019, @08:46PM (2 children)
My understanding is that Earth had a primarily CO2 atmosphere very early in its development, until the evolution of cyanobacteria that reduced it to Oxygen. I don't believe they could have evolved if the seas were boiling.
(Score: 3, Interesting) by HiThere on Wednesday June 12 2019, @10:18PM (1 child)
Yes, but Earth is further from the sun, and whether they could have evolved on dust floating in the atmosphere is an unanswered question.
OTOH, I'm dubious about that extreme scenario too. But high temperatures within limits aren't an obstacle for life. There are microbes that live down in rocks where the temperature is well above the boiling point of water at standard pressure...just not where they're living.
The point is, the atmosphere currently being inhospitable doesn't mean it couldn't BECOME hospitable. And life evolved on earth long before the cyanobacteria evolved. (I was under the impression that it was supposed to be largely ammonia and methane back then, though this wouldn't rule out a large CO2 component. The ammonia was supposed to be the source of the current Nitrogen. This may not be the current thinking.)
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 0) by Anonymous Coward on Thursday June 13 2019, @02:48AM
The sun used to be dimmer. It has been slowly brightening for billions of years.
(Score: 2) by Osamabobama on Wednesday June 12 2019, @10:20PM
The point of the high CO2 concentration was to compensate for the distance from the star "at the outer edge of the conventional habitable zone". Without the high CO2 level, the seas would be frozen.
Appended to the end of comments you post. Max: 120 chars.
(Score: 2) by Hartree on Wednesday June 12 2019, @08:37PM
"You're not in Kansas anymore. You are on Pandora ladies and gentlemen."
Odd. Those Navi and their critters seem to do pretty well with a high CO2 level.
(Actually, this isn't a bug, it's a feature. Those high levels of toxic gases will help keep the earthlings from invading!)
(Score: 1, Insightful) by Anonymous Coward on Wednesday June 12 2019, @09:07PM (4 children)
Ah the dangers of extrapolating from a single data point:
https://xkcd.com/605/ [xkcd.com]
(Score: 2) by bob_super on Wednesday June 12 2019, @09:18PM (2 children)
But .. but ... It's MY data point !
Other data points don't matter. There are other data points, but this one is the most important, because it's mine !!
You ... you can go extrapolate all you want with those other floozies. I'm staying here. I don't need you. We have each other, my data point and me.
(Score: 0) by Anonymous Coward on Wednesday June 12 2019, @10:47PM (1 child)
I love how the space nutters accuse others of only one data point, then proceed to spew forth how life could be anywhere and everywhere...
...then offer only one data point ( extremeophiles), or even none at all: "could, maybe, possibly". Look no further than this discussion.
(Score: 0) by Anonymous Coward on Thursday June 13 2019, @03:01AM
'Extremophiles' are not a single data point. It is a generic descriptive class whose only qualification is that the condition be considered extreme. It covers organisms that live in high pressure, low pressure, weird chemicals, elemental deficiencies, extreme dryness, extreme wetness, high heat, low heat, etc.
(Score: 3, Touché) by KritonK on Thursday June 13 2019, @08:23AM
What's wrong about extrapolating from a single data point? Everybody does it—at least, I do.
(Score: 0) by Anonymous Coward on Friday June 14 2019, @08:36AM
Should it not be obvious to _scientists_ that even on Earth we have creatures with blood that do not use hemoglobin? And that a quick google search will show that carbon monoxide is far less toxic to them:
http://www.jbc.org/content/104/2/239.full.pdf [jbc.org]
Maybe the "scientists" actually already knew that but this is a result of the pressure to "publish or perish", so we end up with "studies" and "research" that actually slow down or even reverse scientific progress (the more crap out there, the harder it is to find the gems).