The Sun is our closest star, and is very ordinary. It has a surface temperature of about 6000 C. The centre of the Sun is much hotter, at a temperature of about 15.6 million C.
The Sun turns faster at the equator than near the north and south poles. This is called “differential rotation” and is possible because the Sun is made of gas and has no solid surface.
The Sun is about 4.6 billion years old and is about half way through its lifetime.
The outer layer of the Sun that we actually see is called the photosphere. This is then surrounded by a very thin gas called the corona. The corona can only be seen during a solar eclipse, but is at a temperature of around 1 million C.
On the surface of the Sun we often see dark patches called sunspots. These are slightly cooler areas that have strong magnetic fields. The number of sunspots on the surface of the Sun changes over a length of time of about 22 years. Each sunspot will last from a few hours to a few days.
We also see big loops of hot gas coming from the Sun’s surface. These start and end at sunspots and are called "solar prominences."
As well as a lot of light and heat, the Sun also gives out a stream of very light particles called the “solar wind”. When this meets the Earth’s magnetic field, it causes the Northern and Southern Lights, called aurora.
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Authors: Carolyn Brinkworth and Claire Thomas
Last updated: July 2001