Moon Transits Earth.
ust a few days ago I wrote about the DSCOVR satellite delivering gorgeous views of the Earth from space, but it just massively one-upped itself: Here’s an animation of the Moon passing in front of the Earth as seen by the satellite’s Earth Polychromatic Imaging Camera, or EPIC! And it’s even cooler than that: In the animation, you’re seeing the fully illuminated far side of the Moon!
The Deep Space Climate Observatory, or DSCOVR, was launched on a SpaceX Falcon 9 rocket in February. It was put into an orbit around the Sun that’s about 1.5 million kilometers smaller than Earth’s, in a direction toward the Sun. This region of space is called the first Lagrange point, or L1 point, and due to a quirk of gravity this is a stable configuration, like sitting in the trough between two hills. At this spot, DSCOVR points toward the Earth with the Sun behind the satellite, so it perpetually sees the sunlit day-side of the Earth. Update, Aug. 5, 2015: Oops! I meant to add a link to a description I did of Lagrange points, because they’re cool. Also, technically, the L1 point is metastable, not stable; if nudged, an object there will fall away from the L1 point.