The Visible Sun

A broad-band image shows the Sun as we see it normally-a white or yellow featureless disk, called the photosphere or visible surface. A closer inspection of this telescopic image, however, reveals several dark spots, called sunspots. These appear darker then their surroundings because thay are considerably cooler (at 4,000 K that's about 8 times hoter then your oven) then the average tempetrature of the surrounding photosphere, 6,000 K. Thay generally occur in paips or groups. Sunspots are places were teh Sun's magnetic field emerges from below the photosphere. If we were to keep a daily record of the sunspot positions, we would descover that the Sun rotates from east to west(from left to right in the image) once every 27 days. in the next cuple of years, as the new sunspot cycle begins, spots will occur at latitudes and these spots will rotate at a slightly slower rate.