Oxygen atmosphere without ozone layer

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Discussion Overview

The discussion revolves around the hypothetical scenario of a planet with an oxygen atmosphere but lacking an ozone layer, exploring the implications for life forms, particularly human beings. Participants consider various mechanisms that could lead to the absence of an ozone layer, including astronomical events and geological factors, while debating the feasibility and consequences of such conditions.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant proposes a planet that has undergone a Great Oxygenation Event, suggesting that life forms could exist without an ozone layer, but questions how to achieve this condition naturally.
  • Another participant suggests that a gamma ray burst could temporarily remove the ozone layer by creating NOx in the upper atmosphere, but questions the permanence of such an event.
  • There is speculation about the role of chloromethane as a plant hormone, potentially influencing the conditions on the planet.
  • Concerns are raised about the implications of a gamma ray burst, with one participant arguing that such an event would likely eliminate life, questioning the viability of a planet with only oxygen.
  • Participants discuss the necessary protection against gamma radiation, considering the depth of water required to shield against it and referencing the potential for photosynthesis at significant depths.
  • One participant doubts the feasibility of maintaining an ozone-free atmosphere, noting that the ozone layer tends to regenerate quickly in the presence of UV radiation.
  • There is a suggestion that a nearby pulsar could maintain the absence of an ozone layer, prompting further inquiry into this idea.
  • Another participant mentions that air may provide some protection against gamma radiation, referencing a mathematical model related to gamma-ray attenuation.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the mechanisms that could lead to an ozone-free atmosphere and the implications for life. The discussion remains unresolved, with no consensus on the feasibility or permanence of the proposed scenarios.

Contextual Notes

Participants highlight limitations in their assumptions, such as the dependence on specific astronomical events and the conditions required for life to thrive without an ozone layer. The discussion also reflects uncertainty regarding the long-term stability of an oxygen atmosphere in the absence of ozone.

Czcibor
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OK, so I would like the following idea:
-planet which already had its Great Oxygenation Event and life forms including human beings would be able to breath there freely
-no oxygen layer or any other plausible mechanism which would practically preclude any daily life forms on the surface (all life aquatic, nocturnal, or insaniously shielded)

OK, so how can we get rid of ozone in natural way? Higher amount of fluorine in crust and it comes from volcanoes? Any hard SF idea?

(Brighter star which would have most of its radiation in UV? But they are shortlived...)
 
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Perhaps a gamma ray burst took the ozone-layer out (by forming NOx in the upper atmosphere) but it wouldn't do so permanently.

Perhaps chloromethane is a plant hormone or something, released by an organism that is in turn favored by the conditions it causes?
 
vemvare said:
Perhaps a gamma ray burst took the ozone-layer out (by forming NOx in the upper atmosphere) but it wouldn't do so permanently.

Perhaps chloromethane is a plant hormone or something, released by an organism that is in turn favored by the conditions it causes?

How to get it on permanent basis? A neutron star not far away? (if yes, then how close)
 
Logic tells me gamma ray burst wipes not only the ozone layer, but also life on the planet. Unless it is OK to have a dead planet with just oxygen (but then oxygen level goes down with time).
 
Borek said:
Logic tells me gamma ray burst wipes not only the ozone layer, but also life on the planet. Unless it is OK to have a dead planet with just oxygen (but then oxygen level goes down with time).

http://en.wikipedia.org/wiki/Radiation_protection#Shielding

Which degree of protection against gamma ray would I require? Leaving only 1/1000,000th? In this case 3.6 m of water, so a shallow lake could achieve that.

Because it seems that photosynthesis under perfect conditions can work below 200 m under surface:

http://books.google.pl/books?id=AZC...r_esc=y#v=onepage&q=algae light depth&f=false

(Or do I overlook something?)
 
Two thoughts later: even if it will work (I mean: GRB strong enough to wipe out ozone layer, but weak enough to spare the life), I don't think it will work for your purposes. Ozone layer rebuilds itself on a relatively quick timescale in the presence of UV.
 
Borek said:
Two thoughts later: even if it will work (I mean: GRB strong enough to wipe out ozone layer, but weak enough to spare the life), I don't think it will work for your purposes. Ozone layer rebuilds itself on a relatively quick timescale in the presence of UV.

I don't think about one time GRB, but nearby pulsar. (opinion about it?)
 

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