THE SUN Bob Davis

Stats Diameter: 1,392,000 Mass: 2 × kilograms Age: 4,570,000,000 years Mostly Hydrogen and Helium Surface Temp: 5,778 K Core Temp: 15.7×10 6 K 1,300,000 Earths could fit in the sun, and its mass is 332,900 times the Earth’s mass

Distance million km from Earth About 25,000 light years from galactic center Takes 8m 19s for light from Sun to reach Earth

What does the Sun do all day? Converts hydrogen into helium through nuclear fusion Converts million tons of hydrogen per second Has been doing this for about 5 billion years, will continue for about another 5 billion Will eventually become red giant

Who discovered the Sun? One of the earliest objects of worship Sun gods include Ra, Sol, Helios, Apollo Often carried across sky by boat or chariot Greek Anaxagoras thought it was flaming ball of metal and not Helios- sentenced to death Copernicus created mathematical model of heliocentrism

Galileo observed sunspots Earnest Rutherford thought Sun’s energy came from radioactive decay 1920: Sir Arthur Eddington suggests nuclear fusion as solution 1957: Margaret Burbidge: elements are created in stars

What good is the Sun anyway? Photosynthesis Vitamin D production Most elements