No, this is not a hidden meaning behind the Pink Floyd album. Or a pun about the moon being both a Jedi and a Sith. We are talking about the far or dark side of the moon, our closest neighbor.
NASA’s camera on the Deep Space Climate Observatory (DSCOVR) satellite [launched in February-more information here] captured images of the moon moving in front of Earth last month. These images reveal a fully illuminated dark side of the moon that is NEVER seen from Earth! (The same side of the moon is always facing the Earth because it is tidally locked into an orbital period that is the same as its rotation around its axis).
These images were taken by NASA’s Earth Polychromatic Imaging Camera (EPIC), which is a four megapixel CCD camera and a telescope mounted onto the DSCOVR satellite. This satellite is orbiting 1 million miles away from Earth. You may be wondering how good can a 4 megapixel camera be that far away? EPIC is different from a personal camera because it takes images in narrow wavelength ranges. Once combined, these images help study physical quantities of dust, volcanic ash, cloud height, vegetation cover and ozone in our atmosphere. As a result, the data can provide more knowledge about Earth’s energy balance; an important part of the mission of the DSCOVR satellite.
Typically, DSCOVR’s primary mission is monitoring solar wind for the National Oceanic and Atmospheric Administration (NOAA). Due to this mission, EPIC has a constant view of the sunlit side of Earth. Twice a year, the camera is able to capture images of the moon and Earth together, as the satellite moves across the orbital path of the moon.
This is not the first time we have seen the dark side of our orbital companion. The first time was in 1959, with the Soviet Luna 3 spacecraft. Other missions have seen a similar view such as, the 2008 Deep Impact spacecraft. Most of these images, however, were only able to show a partially illuminated moon. This is the first time we have seen it fully illuminated thanks to the combined narrow wavelength images.