The Donut Around Earth

One of the key issues scientists worry about when visiting other planets is radiation exposure. This has been a persistent worry for years because on Earth, we don’t face this issue; we are protected by the planet’s magnetosphere, which creates the Van Allen Belt.

Earth’s magnetosphere traps high-energy radiation particles and shields us from solar winds and storms–all of which can be incredibly damaging to our health and technology. This trapped radiation forms two belts of radiation, the Van Allen Belts. The shape they form makes it seem like Earth is surrounded by two large donuts (look at the diagram below). The outer belt contains billions of high-energy particles that come from the Sun, whereas the inner belt is comprised of interactions of cosmic rays with Earth’s atmosphere. 

By looking at this diagram, you might be thinking that when astronauts exit Earth, they must go through this belt, so how do they survive this radiation exposure? The short answer is that they must travel really fast through this belt, and this is the reason they wear specialized space suits to mitigate these exposures. Additionally, this radiation exposure may damage the circuits and equipment aboard the spaceship, which is why this belt has been closely studied for years to help understand and find ways to avoid technological casualties. 

Unfortunately for some, you can’t exactly see these belts, but with the right equipment and photographs, you are able to get a sense of what these belts look like and their composition. The belt can extend from a range of 640 to 58,000 kilometers, including both the inner and outer belts. 

Space missions have been launched to study the belt more, with the first mission being as early as 1958 in the Explorer 1 mission. Its studies were quite basic as it had a Geiger sensor (something that measures and detects radiation) and a tape recorder. While the data collected from this mission was scarce, it was enough to allow further space missions to study the belt further, and it was during Explorers 3 and 4 that the two belts were officially detected. 

Stay tuned for more blogs where we will uncover more of Earth’s mysteries and the factors that help us live on this planet!