RE: What do you know today that you didn't know yesterday?
March 26, 2022 at 11:33 pm
(This post was last modified: March 26, 2022 at 11:43 pm by Anomalocaris.)
The oceans of the world exists today because of bacteria.
Water evaporating from the surface of the earth goes into the atmosphere as water vapor, where some of the water molecules in the vapor are dissociated by solar UV into free molecular hydrogen and oxygen. If this is all the oxygen there is in the atmopshere, then hydrogen has low chance of recombining with oxygen to reform water before most of the hydrogen escapes into space..
Because oxygen is a highly reactive molecule, if there is no other process constantly pumping large amount of oxygen into the atmopshere, the oxygen left behind by escaping hydrogen will quickly be leached out of the atmosphere by chemical reaction with soil and rocks, and will not accumulate in the atmosphere to await the next generation of water vapor.
If this process is unchecked the hydrogen in most if the earth’s surface water would have been lost to space by now, and most of the earth’s surface would be a hyper arid desert, in other words, like Mars.
However, it appears this process was largely arrested by early evolution of oxygen photosynthesis in Cyanobacteria. As bacteria undergo photosynthesis they pump free oxygen into the atmosphere. The additional free oxygen did 2 things: 1. Initially, even a trace concentration of free oxygen greatly increases the chance that free hydrogen made by photo dissociation of water would encounter free oxygen and recombine to form water before the hydrogen can escape. There is evidence bacteria has been adding trace amounts of oxygen into the atmophere for 3 billion years. 2. Later when oxygen built up in the atmosphere to a few percent of current concentration, there is enough oxygen in the atmophere to form an ozone layer, which greatly cuts down the amount of UV reaching into lower atmophere to dissociate water vapor in the first place. This is evidence this happened over 2 billion years ago.
It is estimated this reduced the rate of earth’s hydrogen loss into space by two to three orders of magnitude. Instead of losing perhaps 90% of earth surface water to space, earth only lost maybe 20%. With earth’s current atmosphere of 21% oxygen and thick ozone layer, the rate of water loss through hydrogen loss has been so slowed that only 0.1% of earth surface water is lost to space every billion years.
One school of thought concerning why Mars lost much of its water while earth didn’t posits mars lost it simply because oxygen photosynthesis never took off on mars, either because life never arose on mars, or Martian life never evolved oxygen photosynthesis.
So if you visit the beach and enjoy ocean waves lapping at your feet, give thanks not to God but something much greater, the Cyanobacteria.
Water evaporating from the surface of the earth goes into the atmosphere as water vapor, where some of the water molecules in the vapor are dissociated by solar UV into free molecular hydrogen and oxygen. If this is all the oxygen there is in the atmopshere, then hydrogen has low chance of recombining with oxygen to reform water before most of the hydrogen escapes into space..
Because oxygen is a highly reactive molecule, if there is no other process constantly pumping large amount of oxygen into the atmopshere, the oxygen left behind by escaping hydrogen will quickly be leached out of the atmosphere by chemical reaction with soil and rocks, and will not accumulate in the atmosphere to await the next generation of water vapor.
If this process is unchecked the hydrogen in most if the earth’s surface water would have been lost to space by now, and most of the earth’s surface would be a hyper arid desert, in other words, like Mars.
However, it appears this process was largely arrested by early evolution of oxygen photosynthesis in Cyanobacteria. As bacteria undergo photosynthesis they pump free oxygen into the atmosphere. The additional free oxygen did 2 things: 1. Initially, even a trace concentration of free oxygen greatly increases the chance that free hydrogen made by photo dissociation of water would encounter free oxygen and recombine to form water before the hydrogen can escape. There is evidence bacteria has been adding trace amounts of oxygen into the atmophere for 3 billion years. 2. Later when oxygen built up in the atmosphere to a few percent of current concentration, there is enough oxygen in the atmophere to form an ozone layer, which greatly cuts down the amount of UV reaching into lower atmophere to dissociate water vapor in the first place. This is evidence this happened over 2 billion years ago.
It is estimated this reduced the rate of earth’s hydrogen loss into space by two to three orders of magnitude. Instead of losing perhaps 90% of earth surface water to space, earth only lost maybe 20%. With earth’s current atmosphere of 21% oxygen and thick ozone layer, the rate of water loss through hydrogen loss has been so slowed that only 0.1% of earth surface water is lost to space every billion years.
One school of thought concerning why Mars lost much of its water while earth didn’t posits mars lost it simply because oxygen photosynthesis never took off on mars, either because life never arose on mars, or Martian life never evolved oxygen photosynthesis.
So if you visit the beach and enjoy ocean waves lapping at your feet, give thanks not to God but something much greater, the Cyanobacteria.