These videos show some of the larger scale effects of flares on the Sun. In the video, you can see two big eruptions approximately 10 and 17 seconds into the video, from the active region in the lower left.

But look more closely – can you see a wave of coming out of each of these explosions? They are faint, and can be difficult to see, but they are there. These are examples of EIT waves, so called because they were first seen in the SOHO–EIT instrument. These waves are thought to be examples of magnetohydrodynamic waves that propagate in the corona. They are truly large waves; for comparison, the radius of the Earth is about 1/100th that of the Sun. By studying these waves we can learn more about the structure and properties of the solar corona. There is also some evidence that these waves have ‘knock-on’ effects on other parts of the Sun, perhaps causing other events at parts distant from the original explosion. Look at the video – what do you think?