The Sun

The Sun is our closest star. It is classified as G2, which means that it is very ordinary. It has a surface temperature of about 6000K and an apparent magnitude of –26.7, but its absolute magnitude is only 4.83. The core of the Sun is at a temperature of about 15.6 million K, and is at a density of around 148000 kg/m³.


The Sun displays differential rotation, which means that it rotates faster at the equator than near the poles. The rotation period at the equator is about 25.4 days, while near the poles it is about 36 days. This is possible because the Sun is made of gas and has no solid surface.

Stars

If you look up at the sky on a clear, dark night it is possible to see between 2000 and 4000 stars with the naked eye, but these are just a few compared to the many billions that exist. All of the stars that we see belong to our own galaxy, the Milky Way, and this is just one of many millions of galaxies that make up the Universe. There are more stars in the Universe than there are grains of sand on every beach in the world.