The Sun as our nearest stellar neighbor
is a fantastic way to learn more about all the other stars in the Universe.
The picutre seen above is the Sun as seen through a NASA satellite.
The picture
appears green because it is taken
through an Iron filter, so the brighter spots on the image
are where there is more iron than
in the darker regions.
The center of the Sun is extremely
hot, pushing 15 million degrees Centigrade. The pressure is
also incredible, somewhere around
100 billion times that of the pressure here on the earth. Because
of this combination of heat and
pressure the atoms are so close together that they fuse together.
Two protons, and two neutrons will fuse together to become a helium atom
plus some light.
In every single second of every single day the sun expends 700 billion tons of hydrogen in this way. And only a VERY small fraction, less than one percent is turned into light. It would take 4.5 billion years for half of the hydrogen in the sun to be turned into helium.