One Strange Shield

About a year ago National Geographic released a television series titled “One Strange Rock.” It can be found on Disney+. This series looks at how life on Earth survives and thrives. It is especially interesting because it tells this story through eight astronauts (and Will Smith!) who have spent about 1,000 days in space. An easier way to describe it is “if Michael Bay directed a nature documentary.” It’s very dramatic and has very well done cinematography and graphics. There are times when the Earth Scientist in me is a little upset at how they describe things, but overall it is very scientifically sound. One of the episodes is titled “Shield” and tells the story of how the Earth’s magnetosphere protects our planet.

Earth’s magnetosphere is one of the reasons that our planet can harbor life. As a reminder, a magnetosphere is an area surrounding a planet in which charged particles are affected by that planet’s magnetic field. A planet with an active interior creates a magnetic field, which deflects harmful cosmic radiation in solar winds. Earth’s magnetosphere is the reason we have kept our atmosphere. In space, astronauts are exposed to these harmful particles. Mars, which does not have an active core and magnetic field, lost its atmosphere long ago.

The Sun also has a magnetic field, and it can be extended by solar winds, just as Earth’s magnetosphere is shaped by its interaction with solar winds. In 2008, the NASA THEMIS mission discovered that when the Earth is lined up as directly South or North of the Sun’s magnetic field, 20 times the amount of cosmogenic radiation gets past our magnetic field. Does this mean that Earth could eventually lose its atmosphere like Mars? Not anytime soon. Increased solar radiation can harm satellites, cause power outages, and more. With the information from the THEMIS mission we can better predict and prepare for these problems!