In Australia scientists have found the oldest fossil on Earth and they are saying that in their microscopic discovery that there is evidence that convinces them that bacteria and cells were able to thrive more than three point four billion years ago in an oxygen-free world, just like Mars is. What the finding suggests is that early life was sulphur-based which means they were living off and metabolizing sulphur instead of oxygen for energy. This discovery supports the idea that similar life forms could exist where oxygen levels are non-existent or low.
The microfossils that were found were clearly preserved and they showed precise cell-like structures. These tiny fossils were preserved between the quartz sand grains of the oldest shore line on Earth in some sedimentary rocks that were the oldest ever discovered. By analyzing these fossils and the rocks in which they were found, the picture the scientists have painted of Earth back then was a hot, violent, murky place in which there was a high constant threat of meteor strikes and volcanic eruptions.
The scientists say the skies would have been grey and cloudy which kept the heat in even though the sun would have probably been weaker then than today and the oceans would have been the temperature of a nice hot bath, around forty to fifty degrees Celsius. Because there were not algae or plants to photosynthesize and produce oxygen, there would have been very little of it around.
It would not have been a great place for humans but it would have been a wonderful place for bacteria and was the perfect place for life to emerge.