The Sun

An X-ray picture of the Sun

Credit: Yohkoh and Calvin J. Hamilton

It contains more than 99.8% of the total mass in the Solar System, with Jupiter having most of the rest.

It is about 4,500 million (4,500,000,000) years old and will probably stay almost the same for another 5,000 million years before "dying".

The Sun is a very active place (as you can see from the X-ray picture). The amount of activity changes from day to day and year to year.

All the energy from the Sun is produced in the core by nuclear fusion.

It takes about 50 million years for this energy to make its way out to the surface! And then about another 8 minutes for the light to reach the Earth.