On Sept. 13, 2015, as NASA's Solar Dynamics Observatory, or SDO, kept up its constant watch on the sun. Just as the moon came into SDO's field of view on a path to cross the sun, Earth entered the picture, blocking SDO's view completely.
Three substantial coronal holes rotated across the face of the Sun the week of Sept. 8-10, 2015 as seen by NASA's Solar Dynamics Observatory. Coronal holes are areas where the Sun's magnetic field is open and a source of streaming solar wind.
This still image from an animation from NASA GSFC's Solar Dynamics Observatory shows a single plume of plasma, many times taller than the diameter of Earth, spewing streams of particles for over two days (Aug. 17-19, 2015) before breaking apart.
This still image from an animation from NASA GSFC's Solar Dynamics Observatory shows magnetically charged particles forming a nicely symmetrical arch at the edge of the Sun as they followed the magnetic field lines of an active region (Aug.4-5, 2015).
Tracking Sunspots from Mars, April 2015 (Animation)
This single frame from a sequence of six images of an animation shows sunspots as viewed by NASA's Curiosity Mars rover from April 4 to April 15, 2015. From Mars, the rover was in position to see the opposite side of the sun.
Tracking Sunspots from Mars, Summer 2015 (Animation)
This single frame from a sequence of images shows sunspots as viewed by NASA's Curiosity Mars rover from June 27 to July 8, 2015; the rover was in position to see the opposite side of the sun from the side facing Earth during this period.
Flaring, active regions of our sun are highlighted in this image combining observations from several telescopes. During the observations, microflares went off, which are smaller versions of the larger flares that also erupt from the sun's surface.
This still image from an animation from NASA GSFC's Solar Dynamics Observatory shows dark strands of plasma hovering above the Sun's surface beginning to interact with each other in a form of tug of war over two and a half days (June 28-30, 2015).
A pair of substantial coronal holes were the most notable features on the Sun over the week of Mar. 28 - Apr. 2, 2015. The images were taken in a wavelength of extreme ultraviolet light by NASA GSFC's Solar Dynamics Observatory.
The image taken by the Oschin Schmidt Telescope, shows the star AC +79 3888, also known as Gliese 445. NASA's Voyager 1 spacecraft, which is on a trajectory out of our solar system, is headed toward an encounter with AC +79 3888 (circled in red).
This artist's concept shows the general locations of NASA's two Voyager spacecraft. Voyager 1 (top) has sailed beyond our solar bubble into interstellar space. Voyager 2 (bottom) is still exploring the outer layer of the solar bubble.
Radio telescopes cannot see Voyager 1 in visible light, but rather "see" the spacecraft signal in radio light. This image of Voyager 1's signal on Feb. 21, 2013. At the time, Voyager 1 was 11.5 billion miles (18.5 billion kilometers) away.