Study shows some exoplanets may have greater variety of life than exists on Earth

Study shows some exoplanets may have greater variety of life than exists on Earth
This artist's concept shows what the TRAPPIST-1 planetary system may look like, based on available data about the planets' diameters, masses and distances from the host star, as of February 2018. 3 of the 7 exoplanets are in the 'habitable zone', where liquid water is possible. See https://exoplanets.nasa.gov/trappist1/ Credit: NASA/JPL-Caltech

A new study indicates that some exoplanets may have better conditions for life to thrive than Earth itself has. "This is a surprising conclusion," said lead researcher Dr. Stephanie Olson, "it shows us that conditions on some exoplanets with favourable ocean circulation patterns could be better suited to support life that is more abundant or more active than life on Earth."

The discovery of exoplanets has accelerated the search for life outside our solar system. The huge distances to these exoplanets means that they are effectively impossible to reach with , so scientists are working with remote sensing tool such as telescopes, to understand what conditions prevail on different exoplanets. Making sense of these remote observations requires the development of sophisticated models for planetary climate and evolution to allow scientists to recognize which of these distant planets that might host life.

Presenting a new synthesis of this work in a Keynote Lecture at the Goldschmidt Geochemistry Congress in Barcelona, Dr. Stephanie Olson (University of Chicago) describes the search to identify the best environments for life on exoplanets:

"NASA's search for life in the Universe is focused on so-called 'habitable zone' planets, which are worlds that have the potential for liquid water oceans. But not all oceans are equally hospitable—and some oceans will be better places to live than others due to their global circulation patterns."

Olson's team modelled likely conditions on different types of exoplanets using the ROCKE-3-D software, developed by NASA's Goddard Institute for Space Studies (GISS), to simulate the climates and habitats of different types of exoplanets.

"Our work has been aimed at identifying the oceans which have the greatest capacity to host globally abundant and active life. Life in Earth's oceans depends on upwelling (upward flow) which returns nutrients from the dark depths of the ocean to the sunlit portions of the ocean where photosynthetic life lives. More upwelling means more nutrient resupply, which means more biological activity. These are the conditions we need to look for on exoplanets."

They modelled a variety of possible exoplanets, and were able to define which exoplanet types stand the best chance of developing and sustaining thriving biospheres.

"We have used an ocean circulation model to identify which planets will have the most efficient upwelling and thus offer particularly hospitable oceans. We found that higher atmospheric density, slower rotation rates, and the presence of continents all yield higher upwelling rates. A further implication is that Earth might not be optimally habitable—and life elsewhere may enjoy a planet that is even more hospitable than our own.

There will always be limitations to our technology, so life is almost certainly more common than "detectable" life. This means that in our search for life in the Universe, we should target the subset of habitable planets that will be most favourable to large, globally active biospheres because those are the planets where life will be easiest to detect—and where non-detections will be most meaningful."

Dr. Olson notes that we don't yet have telescopes which can identify appropriate exoplanets and test this hypothesis, but says that "Ideally this work this will inform telescope design to ensure that future missions, such as the proposed LUVOIR or HabEx telescope concepts, have the right capabilities; now we know what to look for, so we need to start looking."

Commenting, Professor Chris Reinhard (Georgia Institute of Technology) said:

"We expect oceans to be important in regulating some of the most compelling remotely detectable signs of life on habitable worlds, but our understanding of oceans beyond our solar system is currently very rudimentary. Dr. Olson's work represents a significant and exciting step forward in our understanding of exoplanet oceanography."

The first exoplanet was discovered in 1992, and currently more than 4000 exoplanets have been confirmed so far. The nearest known exoplanet is Proxima Centauri b, which is 4.25 light years away. Currently much of the search for life on exoplanets focuses on those in the , which is the range of distances from a star where a planet's temperature allows liquid water oceans, critical for life on Earth.


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Aug 22, 2019
This is actually a pretty interesting hypothesis, in several ways.

First, the signatures that can be detected by telescopes at our distance of various ocean circulation models should be quantified; admittedly it's unlikely that we can detect them with current equipment, but we're improving that all the time.

Second, while the science to make bigger and bigger telescopes exists, it's now a matter of engineering practice and we no doubt have hundreds of years to go before it's a reality. We can only hope that these signatures can be detected with what we have; if not, then we have to wait.

Third, I'm not sure I'd like to visit a planet where the conditions for life were much better than Earth; this would provide more ecological niches and therefore a wider genome, more likely to intersect with our own.
[contd]

Aug 22, 2019
[contd]
Continuing the third theme, people exposed to the atmosphere of such a planet could be found an hour, or a week, or a year later dead with fungus growing out of their mouths and other orifices I will avoid mentioning out of delicacy. This has been a theme of speculative science fiction since the 1940s at youngest. Scholars could probably pick out various explorations of it well back into the 19th and even 18th centuries.

Fourth, greater understanding of life and the conditions to encourage and even engender it will always be valuable no matter what we find.

Food for thought.

Aug 22, 2019
[contd]
Continuing the third theme, people exposed to the atmosphere of such a planet could be found an hour, or a week, or a year later dead with fungus growing out of their mouths...
It would be a fluke if any exoplanetary fungii found humans any more a growth-medium than a rock. The least of its problems would be the inability to enzymatically break down a DNA-based carbon source, if DNA is simply a happenstance out of dozens of conceivable self-replicating carbonaceous/nitrogeous code-carrying chains. More problematic is the very strange fact of a likely confrontation with a strictly optically levorotary set of amino-acids. Earth life will have it no other way, and if the fungus required any dextrorotary alanine, and was only provided the Earthling's levorotary isomer, well, again there's your useless rock.

Aug 23, 2019
"We have used an ocean circulation model to identify which planets will have the most efficient upwelling and thus offer particularly hospitable oceans. We found that higher atmospheric density, slower rotation rates, and the presence of continents all yield higher upwelling rates."

That might resemble venus, but due to slow rotation, one side heated so much and with greenlight gases such as H2SO4, that whole planet is life unstable. Water will not be stable in slow rotation. I think author didn't see all aspects.

Aug 23, 2019
Another aspect which may sound like science fiction but may actually be something so common it goes under our scope, is the possibility of an entire planetculture, or world farm, managed by AI's to feed a void borne civ 2 type civilization. This type of planet might not have a "higher atmospheric density, slower rotation rates, and the presence of continents" as it would be mega landscaped, or geoengineered. This means all original mountains and seas would be relocated and it would be a perfectly smooth green sphere dotted with blue lake dots and a branching irrigation river system. No one, aside from the allotted pollinators and beneficial micro fauna, would live on the planet as the AI's would manage everything. It would be a massive food producing machine to feed trillions of space faring aliens.

Aug 23, 2019
This article gets way ahead of the proven data...supposition run amok.

Aug 23, 2019
ocean circulation models

This article gets way ahead of the proven data...supposition run amok.


Totally. Detecting an ocean would be amazing. Circulation models? Ugh.

Aug 23, 2019
I agree. This article is WAY ahead of even reasonable speculation. I do like that it does recognize a sense of habitable zone(s). But, then it leaps past other zones. It speaks of "higher atmospheric density, slower rotation rates, and, the presence of continents all yield higher upwelling rates." How much higher density? Before our moon-forming event, our atmosphere was VERY dense, precluding life with lungs. Slower rotation rate has serious problems. Our going from 3-4 hours to 24 hour days with the help of the moon (and sun some), is critical to advanced life. Too slow, and we have problems.
Cont'd...

Aug 23, 2019
...
What about other habitable zone such as UV, with sun larger or smaller than our G2-star the UV and water zone will not coincide? Plus photosynthesis habitable zone, even having moon to stabilize obliquity, and more.
Planet with "better conditions for life?" With our 8.7 million eukaryotic species (6.5 million land; 2.2 million marine), we are pretty well packed. We need every biome type we have.
And, "higher upwelling rates?" Oceanic? Many of these planets are likely covered with hundreds of miles of all water. Even super upwelling, could be problematic if the ocean is so deep that the bottom is ice (by compression), thus not having (water) contact with land-type ocean bottom. (not optimal)
I could go on. I say keep looking for life. But, too wild a speculation just makes non-scientists become more jaded over science in general. (I just think we are a little "over our skis" here)

Aug 23, 2019
the real & sane science commentators covered most of the issues with their thoughtful speculations

however what has been left out of the research & follow-up comments?
is our own experience with the Earth's intelligent lifeforms

starting with cephalopods with the advantage of versatile tentacles, each with a brain node
after a half-billion years?
their most recognized achievement is calamari

amphibians were the next to the plate with the additional advantage of deft digits & able to breathe water
that didn't last long before reptiles, adapted to living on land, changed their minds & went back to the sea

this would repeat with dinosaurs, mammals & avians
retaining air-breathing as a super-charger for power, speed & smarts

& it really hasn't mattered for developing technology
all these brainy species,
with & without digits,
have been lost in "the Whale Dream"

so much for bogus "math" estimates dictating our fantasies at the Universe!

Aug 23, 2019
This is not very surprising, we have older papers that find better stars (slightly smaller stars are much more frequent) and planets (slightly larger planets have much more real estate so can support more biomass). But as the article notes, we need to research this now since it has ramifications for the next generation telescopes.

Speaking of which:

author didn't see all aspects.


No paper can cover "all" aspects. But generic water stability is included climate models (while some losses are not - again not "all" aspects) - it is important.

- tbctd -

Aug 23, 2019
- ctd -

supposition run amok

ahead of even reasonable speculation ... just makes non-scientists become more jaded over science


The article covers why it is not supposition or speculation anymore than usual but research, and targeted for preparation to boot.

And while we should reasonably try to listen to the tax paying public, it goes both ways. The public may not understand what is going on despite clearly stating it (see here!). They must accept that the experts reliably produce results. Science has produced the internet & terminals we use, say.

If people use "supposition" and "speculation" on their own, and get jaded ... All we can do is to provide education and explain again. And note that some will never get it, unless they learn how to learn [ https://en.wikipe...r_effect ].

Aug 23, 2019
Earth life will have it no other way, and if the fungus required any dextrorotary alanine, and was only provided the Earthling's levorotary isomer, well, again there's your useless rock.

Let me first note that parasites and diseases has to coevolve with a host. Prokaryotes are essentially harmless for eukaryotes, the new sequencing estimates puts some million of genus (at 95 % clustering) so tens of millions of taxa (at 99 % clustering), but disease causing are a few hundred. Eukaryotes are essentially parasites, of the roughly some number of species as taxa about half are parasites.

So the genetic enzyme producing system is set up as left chiral amino acids (with independently right chiral sugars and right chiral nucleotides). But molecules tend to tunnel to the other chirality over time and added to that evolution produces useful right chiral nucleotides on purpose precisely because they are less common and harder to handle.

- tbctd -

Aug 23, 2019
another bogus issue is the fabulists tediously repeating
threats of alien invasion

we, all of us reading these comments.
have good cause for a guilty conscience

so make an effort to ignore popular entertainments
& apply some reason & rational thought to the subject

start with the aliens would need to be tool-users, starting with the key to industry, controlling fire
surviving the consequences

if these aliens have achieved the capability of being able to observe our world & determine that it is an "Living World"?
their technology & scientific knowledge are centuries beyond ours
even more so if they can deduce our world is inhabited by another "alien-to-them" species

i would presume that their own biological sciences would be equally advanced to their astronautic sciences
that they would understand the dangers of mixing two biospheres
each with billions of years of root-hog-or-die evolution to differentiate the biomes

- cont'd -

Aug 23, 2019
- ctd-

The last two decades medicine/biology has found human/prokaryote enzymes that take peptides from one chirality to the other for all sorts of reasons (reuse, defense, attack).

Before our moon-forming event, our atmosphere was VERY dense, precluding life with lungs. Slower rotation rate has serious problems. Our going from 3-4 hours to 24 hour days with the help of the moon (and sun some), is critical to advanced life. ... having moon to stabilize obliquity


You have that backwards, since Earth rotation has slowed without problem and since Tellus (proto-Earth) atmosphere was likely thin and so was Earth atmosphere initially after the Moon forming event. Outgassing happened over time.

Our Moon contribute very little to obliquity stabilization, c.f. Mars which is a much smaller planet or Venus which is same size. And what if it didn't? A less stable climate, so more diversity evolves, which is the variety the article discuss!

Aug 23, 2019
- cont'd -

an important issue is that our supposed advanced aliens survived their own versions of weapons of mass destruction
as well as ecological catastrophe from abusive practices such as primitive industrial processes

leaving them poorer but wiser from centuries of clean-up & recovery

if they are observing us in real time?
why would they assume we will be capable of repeating their success at survival for their species & biosphere?

what they will see is a greed motivated, low-intelligence species cheerfully destroying themselves & all Earth life

if the alien technology was advanced enough to enable their intervention?
they must be smart enough to realize our determination at committing Matricide
& we would take advantage of their rescue efforts to annihilate their species & world

or, if they ain't smart enough to invent the advanced tech to see us or reach us?
thereinbye avoiding joining us primitive savages in suicidal extinction?

the aliens would be just smart enough!

Aug 23, 2019
"Study shows some exoplanets may have greater variety of life"
Based on what we now know this is possible.

"Unicorns only hover over virgin females"
Based on what we now know this is possible.

We have exactly the same amount of observed data for both above premises. Click, click, click, click, every click is revenue for someone.

Aug 26, 2019
This is why oumuamua reconnoitered our blue planet on its slowboat gravity assist survey.

Aug 26, 2019
The question has been answered: We are NOT alone.

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