Ultraviolet Sun

This image shows the solar disc as observed by SOHO's Extreme Ultraviolet Imaging Telescope (EIT) at a wavelength of 171 Å, corresponding to emission lines by highly ionized iron atoms (Fe IX/X). This filter probes material in the lower corona, at a temperature of about 1 million Kelvin.

Spots and loops are clearly visible throughout the solar disc, yielding a lot of information about the Sun's magnetic field: loops correspond to closed magnetic field lines, whereas dark spots correspond to open magnetic field lines, extending into outer space.

Photo credit: ESA/NASA - SOHO/EIT

The Changing Face of the Sun Over One Solar Cycle

This image shows a sequence of snapshots of the Sun, taken each year over almost an entire, 11-year long solar cycle. The activity clearly peaks around the year 2001.

The images have been taken by SOHO's Extreme ultraviolet Imaging Telescope (EIT) at a wavelength of 284 Å, corresponding to the emission line of fourteen-times ionized iron atoms (Fe XV) and showing material at temperatures of about 2 million Kelvin.

Photo credit: ESA/NASA - SOHO/EIT