Sun Spots

In Aztec myths there is a legend of creation saying that there was a god with a scabby, pock-marked face who sacrificed himself to create the sun, which suggest that they saw spots on the sun. Galileo turned his telescope towards the sun and said that there were spots on it, and all of the European astronomers were puzzled. The discovery was ground breaking. The credit is usually shared by Johann Goldsmid of Holland, Galileo Galilei of Italy, Christopher Schiener of Germany, and Thomas Herriot of England all of whom said they saw sun spots at some point in 1611. By observing the sun for a period of time Galileo saw that the sun spots got smaller in size as they approached the visible edge of the sun. He figured that this could not happen if the spots were moons or planets moving between the earth and the sun.

Sunspots are made up of two parts: a dark, roughly circular central disk called the umbra, and a lighter outer area called the penumbra. The sun spot is essentially a part of the sun which is cooler than the area surrounding it. The reason that the sun spot is cooler is because of a magnetic field which hinders the transportation of heat from the sun. A sun spot has an average temperature of 4000 degrees Kelvin. The magnetic field has the power to cool down the surface of the sun by one third. An average sized sun spot is measured to be about the size of the earth. For over 150 years we've known that sun spots appear in cycles, increasing and decreasing on a regular cycle of between 9.5 to 11 years, on average about 10.8 years. Heinrich Schwabe was an amateur astronomer when he figured the cycle, he noted this in 1843.