Sunspots
Very interesting…
Our Sun is always too bright to view with the naked eye, but it is far from unchanging. It experiences cycles of magnetic activity. Areas of strong activity manifest as visible spots—sunspots—on the Sun’s surface. The year 2008, however, earned the designation as the Sun’s “blankest year” of the space age. Our Sun experienced fewer spots in 2008 than it had since the 1957 launch of Sputnik. As of March 2009, the Sun was continuing its quiet pattern.
These images from the Solar and Heliospheric Observatory (SOHO) spacecraft compare sunspots on the Sun’s surface (top row) and ultraviolet light radiating from the solar atmosphere (bottom row) at the last solar maximum (2000, left column) and at the current solar minimum (2009, right column.) The sunspot images were captured by the Michelson Doppler Imager (MDI) using filtered visible light. On March 18, 2009, the face of the Sun was spotless.
The other set of images, acquired by the Extreme Ultraviolet Imaging Telescope (EIT), shows ultraviolet light radiating from the layer of the atmosphere just above the Sun’s surface. This part of the solar atmosphere is about 60,000 Kelvin—a thousand times hotter than the surface of the Sun itself. On July 19, 2000, the solar atmosphere was pulsating with activity: in addition to several extremely bright (hot) spots around the mid-latitudes, there were also numerous prominences around the edge of the disk. On March 18, 2009, however, our star was relatively subdued.
