On Sept. 13th, the sun was eclipsed--twice! No one on Earth has ever seen anything like it. Indeed, it was only visible from Earth orbit. NASA's Solar Dynamics Observatory (SDO) recorded the event:
NASA's Solar Dynamics Observatory was just sitting around in orbit doing its job, capturing images of the sun. It had a clean line-of-sight until that prankster Earth and its sidekick the moon got in the way.
This all happened on September 13, a day of a partial solar eclipse that was visible from South Africa, Antarctica and the southern Indian Ocean on our Blue Marble.
The Solar Dynamics Observatory is accustomed to seeing the occasional Earth or moon-caused eclipse, but Sunday was special due to the two of them transiting the sun in tandem. "Though SDO sees dozens of Earth eclipses and several lunar transits each year, this is the first time ever that the two have coincided," NASA notes.
NASA published a video of the "double photobomb" on September 14 showing the moon coming into the frame and then Earth arriving to block the observatory's view of the sun completely. When the Earth finally gets out of the way, it is just in time for the SDO to see the tail end of the moon heading out of the picture.
On Sept. 13, 2015, as NASA’s Solar Dynamics Observatory, or SDO, kept up its constant watch on the sun, its view was photobombed not once, but twice. 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. When SDO's orbit finally emerged from behind Earth, the moon was just completing its journey across the sun’s face.
Though SDO sees dozens of Earth eclipses and several lunar transits each year, this is the first time ever that the two have coincided. SDO’s orbit usually gives us unobstructed views of the sun, but Earth’s revolution around the sun means that SDO’s orbit passes behind Earth twice each year, for two to three weeks at a time.
During these phases, Earth blocks SDO’s view of the sun for anywhere from a few minutes to over an hour once each day. Earth’s outline looks fuzzy, while the moon’s is crystal-clear. This is because—while the planet itself completely blocks the sun's light—Earth’s atmosphere is an incomplete barrier, blocking different amounts of light at different altitudes. However, the moon has no atmosphere, so during the transit we can see the crisp edges of the moon's horizon.
This video is public domain and can be downloaded at: http://svs.gsfc.nasa.gov/goto?11993
The Earth's atmosphere makes its edges look fuzzy compared to the moon's sharply defined circle.
The Solar Dynamics Observatory launched in 2010 on a mission to study solar activity to help scientists better understand how changes on the sun impact Earth. It is in an orbit that allows it to have a mostly uninterrupted view of the sun. It just so happens that Sunday was the most spectacular interruption in its history.