Scientists discover a new origin of oxygen on Earth and in space

Found: A new way to get oxygen from carbon dioxide, no plants involved
Scientists have discovered a new way to make molecular oxygen (O2) from carbon dioxide (CO2) -- no green plants involved.

Their findings could alter our understanding of the Earth's early atmosphere and how oxygen might form on other planets with carbon dioxide in their atmospheres.

In a paper published Thursday in Science, researchers from UC Davis report that when carbon dioxide molecules are exposed to certain wavelengths of light radiation, they can get so excited that they split into a C molecule and an O2 molecule.
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Calilasseia wrote:This isn't new. Here's a paper on this from the year 2000.

Calilasseia wrote:This isn't new. Here's a paper on this from the year 2000.

Photodissociation of CO2 by ultraviolet light (λ = 185 nm) generates CO and O2, which are unusually enriched (more than 100‰) in 17O. The dissociation takes place through a spin forbidden process during transition from a singlet to a triplet state, the latter lying on a repulsive potential energy surface. The 17O isotopic enrichment is a primary process associated with this transition and could be due to near resonant spin-orbit coupling of the low energy vibrational levels of the 16O12C17O molecule in the singlet state with those of the triplet state near the zone of transition. In contrast, photodissociation at shorter wavelengths (λ < 160 nm) involves no spin violation and produces CO and O2 which are fractionated in a conventional mass dependent fashion. The proposed explanation is further supported using 13C enriched CO2; in this case the products are enriched in both heavy isotopes but about 100‰ more in 18O. The 17O enrichment in CO and O2 generated by CO2 photolysis in a range of UV wavelengths may be a useful tracer in delineating processes in the atmospheres of Earth and Mars.

Cito di Pense wrote:Here on earth, the evolution of photosynthesis was a catastrophe for anaerobic bacteria.

Cito di Pense wrote:All this says is that if you detect oxygen in the atmosphere of an extrasolar planet, it's not necessarily diagnostic of green plants down below. The tiny amounts of molecular oxygen that can be produced by, e.g., photodissociation of CO2 (not to mention H2O) will rapidly react with other molecular gases in the atmosphere, such as CO, CH4, H2S or atomic species which are even more reactive. Should that not be sufficient to convince you that not much free molecular oxygen will result, if there are any rocks on the planetary surface containing iron, there's another reservoir for soaking up molecular oxygen. Thus the concentration of oxygen in any planetary atmosphere above a planet not harboring green plants is likely to remain very, very low. Here on earth, the evolution of photosynthesis was a catastrophe for anaerobic bacteria. Earth's oxygen (at biologically-significant levels) is the outcome of photosynthesis. I don't think anyone participating in this thread will doubt this.

juju7 wrote:

Cito di Pense wrote:All this says is that if you detect oxygen in the atmosphere of an extrasolar planet, it's not necessarily diagnostic of green plants down below. The tiny amounts of molecular oxygen that can be produced by, e.g., photodissociation of CO2 (not to mention H2O) will rapidly react with other molecular gases in the atmosphere, such as CO, CH4, H2S or atomic species which are even more reactive. Should that not be sufficient to convince you that not much free molecular oxygen will result, if there are any rocks on the planetary surface containing iron, there's another reservoir for soaking up molecular oxygen. Thus the concentration of oxygen in any planetary atmosphere above a planet not harboring green plants is likely to remain very, very low. Here on earth, the evolution of photosynthesis was a catastrophe for anaerobic bacteria. Earth's oxygen (at biologically-significant levels) is the outcome of photosynthesis. I don't think anyone participating in this thread will doubt this.

I do. You have failed to show that oxygen levels will be very low, and you don't explain why there should be reducing conditions in an atmosphere.

Cito di Pense wrote:
Oxygen is very reactive, reacting quickly with other atmospheric species to make oxidized compounds like water, carbon dioxide, carbon monoxide and nitrogen oxides. When there is not a continuous supply of molecular oxygen, its concentration in a reducing atmosphere (an atmosphere without a continuing supply of oxygen) will remain low. Learn some fucking chemistry, for fuck's sake.

ScholasticSpastic wrote:Chemistry is a skeptic's friend.

Cito di Pense wrote:The next time chemtrails come round, you show 'em how it's done.

Cito di Pense wrote:

juju7 wrote:

Cito di Pense wrote:All this says is that if you detect oxygen in the atmosphere of an extrasolar planet, it's not necessarily diagnostic of green plants down below. The tiny amounts of molecular oxygen that can be produced by, e.g., photodissociation of CO2 (not to mention H2O) will rapidly react with other molecular gases in the atmosphere, such as CO, CH4, H2S or atomic species which are even more reactive. Should that not be sufficient to convince you that not much free molecular oxygen will result, if there are any rocks on the planetary surface containing iron, there's another reservoir for soaking up molecular oxygen. Thus the concentration of oxygen in any planetary atmosphere above a planet not harboring green plants is likely to remain very, very low. Here on earth, the evolution of photosynthesis was a catastrophe for anaerobic bacteria. Earth's oxygen (at biologically-significant levels) is the outcome of photosynthesis. I don't think anyone participating in this thread will doubt this.

I do. You have failed to show that oxygen levels will be very low, and you don't explain why there should be reducing conditions in an atmosphere.

How long did it take you to come up with that boner? It's looking like more than a year.

Oxygen is very reactive, reacting quickly with other atmospheric species to make oxidized compounds like water, carbon dioxide, carbon monoxide and nitrogen oxides. When there is not a continuous supply of molecular oxygen, its concentration in a reducing atmosphere (an atmosphere without a continuing supply of oxygen) will remain low. Learn some fucking chemistry, for fuck's sake.

juju7 wrote:

Cito di Pense wrote:

juju7 wrote:

Cito di Pense wrote:All this says is that if you detect oxygen in the atmosphere of an extrasolar planet, it's not necessarily diagnostic of green plants down below. The tiny amounts of molecular oxygen that can be produced by, e.g., photodissociation of CO2 (not to mention H2O) will rapidly react with other molecular gases in the atmosphere, such as CO, CH4, H2S or atomic species which are even more reactive. Should that not be sufficient to convince you that not much free molecular oxygen will result, if there are any rocks on the planetary surface containing iron, there's another reservoir for soaking up molecular oxygen. Thus the concentration of oxygen in any planetary atmosphere above a planet not harboring green plants is likely to remain very, very low. Here on earth, the evolution of photosynthesis was a catastrophe for anaerobic bacteria. Earth's oxygen (at biologically-significant levels) is the outcome of photosynthesis. I don't think anyone participating in this thread will doubt this.

I do. You have failed to show that oxygen levels will be very low, and you don't explain why there should be reducing conditions in an atmosphere.

How long did it take you to come up with that boner? It's looking like more than a year.

Oxygen is very reactive, reacting quickly with other atmospheric species to make oxidized compounds like water, carbon dioxide, carbon monoxide and nitrogen oxides. When there is not a continuous supply of molecular oxygen, its concentration in a reducing atmosphere (an atmosphere without a continuing supply of oxygen) will remain low. Learn some fucking chemistry, for fuck's sake.

You didn't read my post.
Repeat: Why should there be reducing conditions in an atmosphere?
The atmosphere of Venus, for instance contains no reducing gasses that can react with oxygen.

Learn some manners, mate.

Cito di Pense wrote:

juju7 wrote:

Cito di Pense wrote:

juju7 wrote:

I do. You have failed to show that oxygen levels will be very low, and you don't explain why there should be reducing conditions in an atmosphere.

How long did it take you to come up with that boner? It's looking like more than a year.

Oxygen is very reactive, reacting quickly with other atmospheric species to make oxidized compounds like water, carbon dioxide, carbon monoxide and nitrogen oxides. When there is not a continuous supply of molecular oxygen, its concentration in a reducing atmosphere (an atmosphere without a continuing supply of oxygen) will remain low. Learn some fucking chemistry, for fuck's sake.

You didn't read my post.
Repeat: Why should there be reducing conditions in an atmosphere?
The atmosphere of Venus, for instance contains no reducing gasses that can react with oxygen.

Learn some manners, mate.

Then I guess there should be lots of free oxygen in the atmosphere of Venus, right? Mate? What sorts of processes do you think hinder the accumulation of free oxygen in the present atmosphere of Venus? Could it be that CO2 is a stable compound relative to C + O2 or CO + O* or CO4* + C* (and so on) under conditions found in the Venerian atmosphere? You know what they say: If it happens, it must be possible, and that should answer your feeble inquiry into why oxygen concentration is low in the Venerian atmosphere, unless you'd refuse to consider something like C* (g) a reducing gas species, given stability relations you can easily evaluate for atomic carbon and molecular oxygen and carbon dioxide at T,P(Venus atmosphere).

No one's explaining to you why there should be reducing conditions in an atmosphere because that wasn't the question.

Who says there should be reducing conditions in an atmosphere?

juju7 wrote:
Repeat: Why should there be reducing conditions in an atmosphere?

ScholasticSpastic wrote:Venus is closer to the sun, so one should expect that photodissociation would have contributed more than- or at least equally to- the abiotic origins of oxygen on Venus than on Earth. So where is Venus's oxygen? It has more than enough CO2 to make oxygen from abiotically, and the higher surface temperatures should be expected to aid the process.

Sendraks wrote:

ScholasticSpastic wrote:Venus is closer to the sun, so one should expect that photodissociation would have contributed more than- or at least equally to- the abiotic origins of oxygen on Venus than on Earth. So where is Venus's oxygen? It has more than enough CO2 to make oxygen from abiotically, and the higher surface temperatures should be expected to aid the process.

This is fascinating and I'd like to know more about what is going on here, but chemistry isn't really my forte so I'm kind of reliant on interpreting what I read on Wikipedia at face value. From wiki page on Venusian atmosphere, I'm seeing that oxygen is getting drawn into the sulphuric acid cycle in the atmosphere. Would this explain where the oxygen is going?