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d ~ 231'552'000 km: day 90

You and I can't hear it - but scientists can. This is how it works, even though the Sun is 149, 000,000 kilometres [93,000,000 miles] from earth, surrounded by the vacuum of space which of course sound can't travel through, scientists can record vibrations from the Sun.

The entire Sun vibrates in a complex pattern of sound waves. Think of it like a giant bell. When you hit a bell, sound waves bounce back and forth inside the metal which makes its surface vibrate. If we had a super-powerful microscope we'd be able to see these patterns of vibrations on the surface.

Well scientists listening to the Sun at aren't using a telescope. They are using an instrument called a Michelson Doppler Imager (MDI), which is on the SOHO spacecraft, orbiting the Sun 1,000,000 miles from Earth to record acoustic waves in the Sun.

Just like in the bell, the sound waves bounce from one side of the Sun to the other taking about two hours to cover the 1.4 million kilometers [ 870,000 miles]. When they hit the sides they cause the Sun's surface to oscillate.

The are at such a low frequency our ears can't hear them. So the scientists speed them up 42,000 times which compressed 40 days of recording vibrations into just a few seconds.

These sound waves are very important to scientist studying the Sun. because they travel underneath the Sun's surface and are affected by what's going on inside the Sun. So scientists can use the oscillations to learn about how the structure of the Sun's interior and how it shapes its surface.

Sand Dunes

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