We've been asking two solar physicists called Keith and Andrew what they know about sunspots and the solar activity cycle. For starters, let's look at two pictures of the Sun taken at the same time but at different wavelengths of light. To our eyes wavelengths of light look like colours. So, long wavelengths appear red to our eyes and short wavelengths appear blue.

There are many wavelengths that our eyes cannot even see. You may have heard of some of them: X-rays, infrared, ultraviolet, and radio waves. You can imagine these names as new colours that we can't see with our eyes. The reason we know they are there is because special cameras can take pictures at these wavelengths. Below, the picture on the left is how the Sun looks at wavelengths our eyes can see. The picture on the right was taken with a special X-ray camera.

• Dark blotches, called sunspots,
• The Sun's "surface", called the photosphere,

In X-rays (right) we see:

• X-rays coming from above the surface
• bright swirls where you see sunspots in visible light