Mass Eruption: This image from SOHO on Jan. 4, 2002, shows a coronal mass ejection, or CME, as it shoots out into space -- the disk in the middle is a result of its coronagraph instrument, which blocks the light from the sun so that the fainter solar atmosphere can be seen.

Extreme Solar Flare: The bright flash on the right side of the sun shows the most powerful flare on record -- categorized as an X 28 -- captured in this image by SOHO on Nov. 4, 2003.

Dynamic Solar Atmosphere: A coronal mass ejection, or CME, exploded from the sun on Feb. 18, 2003, at the same time that Comet NEAT, discovered by a ground-based observatory in 2002, entered SOHO's field of view.

Colorful Sun: SOHO watches the sun in several wavelengths of extreme ultraviolet light simultaneously, each of which highlights a different aspect of the sun's surface and atmosphere -- here in an image from May 1998 the wavelengths of 171 angstroms, 195 angstroms, and 284 angstroms have been colorized and combined.

Dancing Loops: On March 18, 2003, SOHO observed two giant ribbons of solar material floating in the atmosphere, known as prominences -- a dozen Earths could fit inside each one.

Lightbulb CME: This image of a lightbulb-shaped coronal mass ejection, or CME, was captured on Feb. 27, 2000, by SOHO's wider-angle coronagraph-- illustrating a text book image of a CME with a spreading outer boundary around a dense, bright center.

January 8, 2002: This image combines observations on Jan. 8, 2002, from two of SOHO's instruments -- one shows the sun itself, the second shows the solar atmosphere. In combination we can see a giant coronal mass ejection spreading out as it blasts away from the solar surface.

Twisted CME: A twisting, helical coronal mass ejection, or CME, is caught on Aug. 2, 1998 by SOHO's coronagraph as it speeds away from the sun. By capturing images of CMEs from many angles SOHO helps scientists better understand their structure.

Solar Ballet: A giant ribbon of solar material -- called a prominence -- flows out into the atmosphere in this image of the sun captured on April 23, 2001.

Solar Snow Flurries: The white, snow-like speckles in this image from SOHO on May 17, 2012, are energetic particles hitting the detector during a radiation storm after a mid-level (M5.1) solar flare.

Mercury Transit: This composite image from SOHO on Nov. 8, 2006, shows a timelapse of Mercury as it transits across the face of the sun.

Graceful Filament: An elongated filament of solar material swirled into space after exploding from the sun's surface in this image captured by SOHO's coronagraph on April 28, 2015, overlaid with a to-scale extreme ultraviolet image of the sun taken by NASA's Solar Dynamics Observatory.

SOHO As Comet Observer: Comet Bradfield passed through SOHO's field of view on April 18, 2004, less than a month after it was originally discovered by an amateur astronomer.

Black Spot on the Sun: This extreme ultraviolet image of the sun, taken by SOHO on July 18, 2013, revealed a large coronal hole, an area on the sun where the magnetic field is open to interplanetary space, sending coronal material flying out in a high-speed solar wind stream.

Comet ISON: This composite image from SOHO on Nov. 28, 2013, shows Comet ISON as it rounded the sun -- coming in from the lower right and exiting through the top right, breaking up during the process.