About the episode
The Earth's magnetic field is very important. It protects us from space radiation and from charged particles that come from the Sun. But the magnetic field, and therefore the protection as well, is not constant.
For example, magnetic north is constantly in flux, drifting further and further away from geographic north. Sometimes the magnetic field reverses, so north becomes south and south becomes north. During this process, the strength of the magnetic field is less.
It also happens that the magnetic field as we know it changes completely. During this geomagnetic journey, the poles can disappear and be replaced by several new poles. Even then, the strength of the magnetic field is much less strong.
The most famous of these events occurred 41,000 years ago. Now, scientists are investigating more closely than ever the impact on Earth.
how do you do that? This can be done by sampling the ice or bottom sediments. It contains particles created by the interaction between space radiation and the Earth's atmosphere. A less strong magnetic field should bind a greater number of these particles.
This is what they saw before the trip 41 thousand years ago. The number of these particles is twice what it is today, which indicates that a large amount of radiation reached Earth at that time.
The better these types of events are investigated, the better we can predict space weather and its impact on Earth.
Read more about the research here: Cosmic rays streamed through Earth's atmosphere 41,000 years ago
