Observing the Solar System It is now thought that the Sun is the center of the solar system – called the heliocentric model - Copernicus It was once thought that the Earth was the center of the solar system – called the geocentric model - Ptolemy

Sun Corona Sunspots Photosphere Prominence Chromosphere Solar Flare Core

The only star in our solar system, the sun, has many parts Core – central region that produces enormous amounts of energy. Nuclear fusion occurs here – that is when hydrogen atoms join to form Helium Photosphere – inner layer of the sun Chromosphere – middle layer of the sun Corona – outer layer of the sun – looks like a halo around the sun Sunspots – areas of gas on the sun that are cooler than the gases around them Prominences – reddish loops of gas that link sunspot regions Solar Flare – gas eruptions sent out into space