Two of the vital things we need to survive on our planet are Oxygen, which makes up about 21% of our atmosphere, and the Earth’s magnetic field. Oxygen, along with around 75% of nitrogen and tiny amounts of rare gases, allows us to breathe. If all of the atmosphere were made up of oxygen, the first flame would have incinerated the world. So, the balance has to be right. The Earth’s magnetic field is also vital to life continuing on this planet. Its job is to protect us from the harmful radiation which comes from the Sun. This is known as the solar wind and consists of x-rays and very high levels of ultraviolet radiation. If we lost it, the harmful effects of this radiation would produce cancers and other deadly conditions. The human population would be forced to live underground or in well-shielded structures.
So, when recent research suggests there is a link between oxygen and the magnetic field, we should take notice. What the scientists did was to compare different datasets. One of these measured the amount of oxygen in the atmosphere going back over 500 million years. There are various ways to measure this, such as analysing fossilised charcoal. The measurement of the magnetic field also went back around 500 million years and was calculated by analysing the “magnetic echoes” left behind in ancient rocks.
Comparing the two sets of datasets showed a close link between the two. This was especially shown when both measurements reached a peak level around 300 million years ago. The difficulty comes about when you try to decide why the link is there. There are three possibilities. One, it could be due to the oxygen affecting the magnetic field or vice versa. The third possibility is that it is due to some third force or chemical intervention. As yet, this remains an unknown.
Researchers are presently concentrating on the peak measurements 300 million years ago. Was there something else happening in this period of time? One thing that does stand out, is that this was the time of Pangea, our last supercontinent. Over millions of years, Pangea very slowly drifted apart to form the continents we know today.
There is a limit to how far back we can go to measure oxygen levels, so the scientists are also looking to other geophysical and geochemical phenomena which might hold the key. We will just have to wait and see, but in the meantime, do everything we can to ensure we keep our oxygen and magnetic field safely in place.
John Pullen 