What makes Earth's atmosphere so special?

rod

Oct 22, 2019
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As space.com report said "We Earthlings think we're oh-so-special. The abundance of oxygen in our atmosphere and the presence of liquid water on the surface of our planet makes our "Pale Blue Dot" stand out in contrast to the other planets in the solar system — a unique and fragile home for life."

Clearly there are some real differences between Earth's, mostly N2O2 atmosphere and other planets in our solar system documented. Perhaps, Earth is special :)

Compare atmospheres found in exoplanet studies too, a small number have atmospheres measured out of an inventory larger than 4300. Example, 'Telescope Teamwork Reveals Gas Dwarf Planet's Atmosphere', https://www.space.com/nasa-telescopes-reveal-exoplanet-atmosphere.html, "The scientists predicted GJ 3470 b's atmosphere would be full of oxygen and carbon, the same elements that are at the root of the water vapor and methane gas observed at Neptune. "Instead, we found an atmosphere that is so poor in heavy elements that its composition resembles the hydrogen- [and] helium-rich composition of the sun,"

Accretion disks observed around young stars contain CO for much of the disk content. 'Modeling the Spatial Distribution and Origin of CO Gas in Debris Disks', https://ui.adsabs.harvard.edu/abs/2019ApJ...878..113H/abstract

HINTS OF YOUNG SOLAR SYSTEMS, https://skyandtelescope.org/astronomy-news/hints-of-young-solar-systems/
 

rod

Oct 22, 2019
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Interesting comment by Cat in post #3. I note we have 4333 exoplanets now reported at this site, http://exoplanet.eu/catalog/, and 4276 exoplanets reported at this site, https://exoplanetarchive.ipac.caltech.edu/index.html

*Adapted* is a very interesting word. At the moment, I am not aware of reports documenting that life adapted on any of the more than 4300 exoplanets documented. Somehow, here in our solar system, Earth is populated with life that *adapted* to the Earth while even planets like Mars or Venus in our solar system, life is not verified as living there today or for example, a fossil record from the past showing life evolved on those planets :)
 
Jun 1, 2020
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There's a real chance, IMO, that we won't find any planet like Earth in most of the galaxy, perhaps all the galaxy. But we can learn from all the rest on how it all works to better help us understand just what we have.

As for CO, I think this is one of those molecules astronomers can locate in clouds and disks, so reports of finding it has a lot to do with the fact it's somewhat easy to identify. [Perhaps I should have read the article, admittedly.]
 
Jun 1, 2020
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Hmmmmm . . . . . . . . . I always thought that probability was a bit iffy!
Well, I would say you're probably right. ;)

The topic of atmospheres is very important since it will likely be the next set of great astronomical data that comes our way in our search for both planets harboring life and ones we could have a summer home (winter home?) :)

But what we've found so far is just a crude, albeit exciting, start. The confirmed number of a several thousand exoplanets comes from just detecting them -- a bump in the photon flux of the host star, a little regular wiggle in the spectral lines, etc. No image of any that would make a nice screen saver; when imaged directly (a handful only) they're just dim dots. We had to go to Pluto to get that one and we can't seem to even find the next one beyond it (i.e. Planet 9).

Nevertheless, with improved spectroscopy from the near-future giant scopes, some of the composition of exoplanet atmospheres will be resolvable by subtracting out the host-star's spectrum. This limits the number since a transiting system is required, but they may be the leading number of observed exoplanets.
 
Jun 1, 2020
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The topic of atmospheres is very important since it will likely be the next set of great astronomical data that comes our way in our search for both planets harboring life and ones we could have a summer home (winter home?) :)
Well, I suppose Venus would be easier to search. ;)
 
Sep 16, 2020
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For life to be in space, to sustain it Life force to be present. One of the main reason for Earth to have life is its position with respect to Sun.

Also the thinking facility is very essential for Life. Each organ in our body functions because of its latent Intelligence.

The observation reveals that looking from Earth the Sun and our Moon appear almost the same Angular size.

The reason for this is the ratio of the distance from Earth to the diameter of the object (Sun and Moon respectively) is almost 107 to 110.

Our search in the Space for this unique coincidence can be a factor to determine life in a planet.

This may be a wild guess based on observation and perspective...
 
Sep 21, 2020
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Earth is a very special planet, designed perfectly to support life. The atmosphere, orbit, water, etc all work together to make life possible. It is not a bad argument to say that life adapted to Earth's atmosphere, except that I have not heard any theories on how life beyond microbes is possible on say Mars or Venus, where the temperatures, atmosphere and conditions (acid rain etc) make more delicate life much more difficult. It seems to me that the only way "advanced" life is possible is with a planet similar to earth. These new ways of making energy and surviving on more harsh planets may be discovered in the future, but for now I think we ae very lucky to have a goldilocks planet like Earth.
 

COLGeek

Moderator
Apr 3, 2020
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Earth is a very special planet, designed perfectly to support life. The atmosphere, orbit, water, etc all work together to make life possible. It is not a bad argument to say that life adapted to Earth's atmosphere, except that I have not heard any theories on how life beyond microbes is possible on say Mars or Venus, where the temperatures, atmosphere and conditions (acid rain etc) make more delicate life much more difficult. It seems to me that the only way "advanced" life is possible is with a planet similar to earth. These new ways of making energy and surviving on more harsh planets may be discovered in the future, but for now I think we ae very lucky to have a goldilocks planet like Earth.
"designed"? Maybe composed or suitable to support life as we know it.
 
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Catastrophe

The devil is in the detail
Just to underline that point . . . . . . . . .

Take Venus. If there were to be life in the clouds (temperature and pressure Earth like) then it would not be the crushing pressure and horrendous temperature that "did life a favour".
 
Jun 1, 2020
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Just to underline that point . . . . . . . . .

Take Venus. If there were to be life in the clouds (temperature and pressure Earth like) then it would not be the crushing pressure and horrendous temperature that "did life a favour".
Yeah, that's very logical, but I'm not sure that extreme conditions automatically rule out abiogenesis since that alone is an extreme circumstances since it has never been observed, likely due to the lack of extreme conditions. [I skipped biology, so I should have put this into question form but it just sounds better as a statement of logic. :)]
 
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Catastrophe

The devil is in the detail
Helio
My point is that extreme conditions would not have caused life in the clouds (if such life were indeed found to exist). possibly more because such life "preferred" i.e., adapted to life in the clouds.
Of course, if such life were "to prefer" extreme T and P then (by definition) it would adapt to those rather than to mild T and P (and, of course, sulphuric acid :) )

Cat
 
Dec 29, 2019
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Earth's atmosphere IS special; it is the product of biological activity and could not have the mix it does without living processes. No others observed show that.
 
Mar 5, 2020
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Take a deep breath, hold it. Did you keel over dead?

Single celled life did provide Earth with an oxygen atmosphere at least a billion years ago.

Our alien ancestors seeded 30+ phyla on Earth during the time of the Cambrian Explosion. The simple argument supporting alien intervention is based on evolution. There were too many distinctive life forms created over too short a period of time.

Where is the super adaptable single celled organism which gave rise to all of these forms in so short a period of time? It never existed. A single celled organism with thousands of complete sets of “spare” genes would be necessary.

The stromatolites currently present in the stromatolite’s niche are likely to be the complex descendants or replacements of ancient stromatolites. Even these (pseudo?) stromatolites appear to be unrelated and distinct from higher life forms.

Stromatolites and other single celled organisms created the oxygen in the atmosphere. Yet these same cells colonies don’t seem to bear any kinship to us.

Some of the single celled life on Earth appears to be indigenous, while most of the complex forms appear to be alien invasive species.

The time scale for producing an oxygen atmosphere might be more time than our alien ancestors had. So, the aliens waited until a planet with a pre-existing oxygen atmosphere comes close enough. The life that was seeded on Earth were optimized for the conditions that were present at that time.

While our Alien Engineers were in the Solar System, did they seed any other planets in the Solar System? Do we have any carnivorous technologically advanced neighbors?

The only thing found in the alien spacecraft shell was a dinner bell?
 

Catastrophe

The devil is in the detail
"Earth's atmosphere IS special; it is the product of biological activity
and
could not have the mix it does without living processes."

Am I understanding this correctly?

It is the ongoing product of biological activity, yes. We breathe in oxygen and breathe out carbon dioxide. Fortunately for us, plants do the opposite. Fortunate also for the plants. Fortunate, that is, in the sense of adaptation to existing circumstances.

It could not have started without the processes brought about by life ?????
Notice this is not in quotes.

However, life obviously started without life being already present. Rather obviously, it started without the mix brought about by life. Therefore, originally, it was not the product of biological activity.

Now we need a discussion on what "biological" means. It is reminiscent of a definition of "organic" as "compounds of carbon" when the carbon dioxide we breathe out is also produced by the non-organic process of combustion with atmospheric oxygen.

"No others observed show that." I am not surprised.

Cat :)
 

Catastrophe

The devil is in the detail
COLGeek, you posted:

" It seems to me that the only way "advanced" life is possible is with a planet similar to earth. "

This is a fair point, but "advanced" life of a different character may well be possible on a dissimilar planet. It might be silicon-based, inhabiting an organic liquid and unable to travel in space, but could be telepathic and even capable of teleportation. Let me play "what if" and indulge in a little science fiction, just for once.

Cat :)
 

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