|
Hotter things give out different wavelengths (that is colours) of light from colder things. If you put an iron rod in a furnace, it will glow red when it is fairly hot, then it will glow yellow, and if it gets really hot, it'll start to look white.
The surface of the Sun, called the photosphere, is at a temperature of about 6,000 degrees. It gives out lots of visible light that our eyes can see, but almost no X-rays.
The gas above the surface of the Sun in the corona, is at a temperature of about 1,000,000 degrees! At this temperature, it gives out almost no visible light that our eyes can see, but it does give out a lot of X-rays.
So in visible light, we can see parts of the Sun that are a few thousand degrees. In X-rays, we can see parts of the Sun that are a million degrees Celsius. The shape and structures of almost everything we see on and above the surface of the Sun has something to do with magnetic fields. Sunspots are seen as dark patches on the solar surface, the photosphere. Above the surface, the gas is trapped in magnetic loops or tubes and is very hot, hotter and denser than the gas around it, so it looks like bright X-ray swirls. We call these active regions.
In the corona, strong magnetic fields can make the temperature hotter than the normal 1,000,000 degrees. In the photosphere, strong magnetic fields seem to make the temperature in sunspots cooler than the normal 6,000 degrees.
|
|