Sunspots
Sunspots are relatively cool, dark patches on the sun's surface. They come in many shapes and sizes; they often appear in groups. These spots are much bigger than the Earth; they can be over 10 times the diameter of the Earths.

Individual sunspots only last for one to two weeks, but the number of sunspots follows an 11 year cycle. The current sunspot cycle will peak in the middle of 2000. Sunspots are visible from Earth.

The sunspot cycle was discovered by S. Heinrich Schwabe in 1843 (he started his observations in 1826).

WARNING: do NOT look at the sun; it can damage your eyes permanently!

UMBRA:
The umbra is the inner, dark, cool (3700 K = 6600 °F = 3400 °C) region of a sun spot. The umbra of a sunspot can be up to 12,000 miles (20,000 km) wide. In the umbra, the Sun's magnetic field is very strong.

PENUMBRA:
The penumbra is the outer, relatively light region of a sun spot. It is shaped like an annulus (a ring) surrounding the darker, cooler umbra.

PORES:
A pore is a small sunspot that doesn't have a penumbra. Pores are up to about 1,500 miles (2,500 km) across and are lighter than a sunspot's umbra.

GRANULATION:
Granulation is solar granules together with intergranular lanes (dark, cool areas between granules where solar material is descending into the surface). Granulation covers the visible surface (the photosphere) of the Sun.

GRANULES:
Granules are regions of the sun where hot solar material comes to the solar surface. Granules are about 600 miles (1,000 km) across and only exist for about 5 to 10 minutes before they fade away. It is almost as though the surface of the Sun is bubbling like a pot of boiling water.

What Causes Sunspots?
Sunspots occur where the sun's magnetic field loops up out of the solar surface and cool it slightly, making that section less bright. These disturbances in the sun's magnetic field make the sunspot about 2700°F (1500°C) cooler than the surrounding area.

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