The Sun, split in half. One side has many jets and dark spots, the other is much more calm.

The Sun when it’s active with flares (left) and quiet (right)

Credit: NASA/SDO

The Sun is a colossal raging ball of heat. Atoms are fused together in its crushing depths, releasing awesome amounts of energy and spewing gigantic flares from its surface. But for the past few years, the Sun has been calmer than usual.

The Sun’s behaviour follows a surprisingly predictable pattern. Over an 11-year period, it gets more and more active, and then calms back down.

Right now, the Sun is ramping back up after a minimum in December 2019. This marks the beginning of a new solar cycle, the 25th since records started more than 250 years ago.

So what causes this strange rhythm? It’s all down to magnetism! You might know that Earth has a magnetic field, which makes a compass point north. The Sun also has a magnetic field, but it isn’t as stable.

In a solar minimum like we’re currently experiencing, the Sun’s magnetic field runs up and down like Earth’s. But over time, it gets twisted into a giant donut. Meanwhile, the Sun becomes more active. Huge flares and dark sunspots appear over the surface, and solar storms shoot particles into space, causing gusts in the solar wind. At the very peak of activity, the poles switch and north becomes south!

Back here on Earth, we probably won’t see much change for a few years. But when solar activity peaks around 2025, you might want to book a holiday to the polar regions of the world. When solar winds hit Earth’s magnetic field, it makes some beautiful light shows – the Aurora Australis and Aurora Borealis!

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One response

  1. Gavan O'Connor Avatar
    Gavan O’Connor

    You repeat the myth that the compass points north. One end points north. The other end points south. In fact it aligns with the magnetic field.

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