The existence of other planets which can be habitable has been our goal for a very long time. In the 19th Century, astronomers thought that aliens might be using canal-based transport connections to traverse Mars.
Right now, we’re living in an age when scientists can study planets, which are light years away from our solar system, and research is still going on: we need to find that planet which is good for humans. The biggest problem? Oxygen. We need a planet that has Oxygen in the atmosphere so that we could breathe.
But how lucky we were to get on a planet with Oxygen from the very first moment? The Earth’s oceans and its atmosphere show that the rise to the levels of Oxygen on today was kind of hardback in the day.
How Did The Earth Get the Oxygen That We Breathe?
They have drawn these conclusions: Earth underwent a three-step rise in the oceanic and atmospheric oxygen levels. The first one was called Great Oxidation Event”, and it took place about 2.4 billion years ago. After that, there was the “Neoproterozoic Oxygenation Event,” which took place at about 400 million years ago. That’s when the oxygen levels reached their modern peak – that of 21%.
But what exactly happened during these three periods, which made the oxygen level increase? We still don’t know yet. There’s one idea that says that new organisms “bioengineered” the planet, and reconstructed the atmosphere and the oceans with the help of their metabolisms.
The rise of land plants about 400 million years ago could have increased the Oxygen from the atmosphere through photosynthesis. They took over the photosynthetic bacteria in the ocean, which were the main oxygen producers in the history of the Earth. There may also be other reasons, such as plate tectonic changes or gigantic volcanic eruptions.