Most days, you can look up and see the Sun shining above. Even if it’s hidden behind clouds, you know it’s there, lighting up the sky. But while the Sun’s light might be relatively constant, its surface is surprisingly active. If you hopped on NASA’s Parker Solar Probe for a closeup view of the Sun, you might see spurts of charged gas called solar flares coming off its surface, or dramatic explosions called coronal mass ejections. These events travel outward from the Sun through space, and sometimes they interact with Earth’s magnetic field, causing space weather.

This week, the National Oceanic and Atmospheric Administration is tracking several coronal mass ejections that could lead to a minor geomagnetic storm in Earth’s atmosphere. People in Canada and the northern United States may be able to see an aurora the evening of Sept. 9, 2026.

The Conversation U.S. has compiled some articles from our archives on space weather, from the science behind how the phenomenon works to how researchers are working to better understand it – and even predict it.

1. What is space weather?

Solar flares and coronal mass ejections are made up of plasma: electrically charged gas. After they explode off the Sun’s surface, they travel through space and may eventually reach Earth. When they run into Earth’s atmosphere, they interact with the magnetic field shrouding our planet.

As explained by Yeimy J. Rivera, Rosa Tatiana Niembro Hernández and Samuel Badman – a team of astrophysicists at the Smithsonian Astrophysical Observatory – this collision with the magnetic field causes space weather, or geomagnetic storms, which produce the northern lights: the beautiful streaks of green or purple you may have had the chance to see across the sky last year.

The Sun also produces the solar wind, which is much different from a breeze you might feel on Earth. The solar wind is a stream of charged particles and magnetic field........

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