Dec 17, 2019 07:16 AM
https://theconversation.com/breathable-a...ght-128648
EXCERPT: . . . most new research continues to diminish the chances of finding other worlds on which humans could live. The biggest stumbling block may be oxygen – human settlers would need a high oxygen atmosphere in which to breathe. So how were we so lucky to evolve on a planet with plenty of oxygen? The history of Earth’s oceans and atmosphere suggests that the rise to present-day levels of O₂ was pretty difficult...
[...] This event-based history of how oxygen came to be so plentiful on Earth implies that we’re very fortunate to be living on a high-oxygen world. If one volcanic eruption hadn’t happened, or a certain type of organism hadn’t evolved, then oxygen might have stalled at low levels. But our latest research suggests that this isn’t the case. We created a computer model of the Earth’s carbon, oxygen and phosphorus cycles and found that the oxygen transitions can be explained by the inherent dynamics of our planet and likely didn’t require any miraculous events.
[...] What is really exciting about all of this is that the oxygenation pattern can be created without the need for difficult and complex evolutionary leaps forward, or circumstantial catastrophic volcanic or tectonic events. So it appears that Earth’s oxygenation may have been inescapable once photosynthesis had evolved – and the chances of high oxygen worlds existing elsewhere could be much higher. (MORE - details)
EXCERPT: . . . most new research continues to diminish the chances of finding other worlds on which humans could live. The biggest stumbling block may be oxygen – human settlers would need a high oxygen atmosphere in which to breathe. So how were we so lucky to evolve on a planet with plenty of oxygen? The history of Earth’s oceans and atmosphere suggests that the rise to present-day levels of O₂ was pretty difficult...
[...] This event-based history of how oxygen came to be so plentiful on Earth implies that we’re very fortunate to be living on a high-oxygen world. If one volcanic eruption hadn’t happened, or a certain type of organism hadn’t evolved, then oxygen might have stalled at low levels. But our latest research suggests that this isn’t the case. We created a computer model of the Earth’s carbon, oxygen and phosphorus cycles and found that the oxygen transitions can be explained by the inherent dynamics of our planet and likely didn’t require any miraculous events.
[...] What is really exciting about all of this is that the oxygenation pattern can be created without the need for difficult and complex evolutionary leaps forward, or circumstantial catastrophic volcanic or tectonic events. So it appears that Earth’s oxygenation may have been inescapable once photosynthesis had evolved – and the chances of high oxygen worlds existing elsewhere could be much higher. (MORE - details)
