Thursday, May 8, 2014

Earthrise Animation

Moon earthrise

Earthrise animation as seen from the Moon.

These are real animations from the Lunar Reconnaissance Orbiter, which usually points straight downward but occasionally shifts its orientation. These are from February 1, 2014.

The pictures are interspersed with dark horizontal bands the way that they are because of the way the orbiter operates. If you study the animation very closely, you will notice that certain features on the earth change color in each of the five slots. The orbiter filters out different light waves in each frame. These are red at the bottom to yellow to blue/violet at the top. In the red filter, something red on the earth would look bright, while on the blue/violet filter, those colors would look bright. The Moon itself has no colors, so it always looks the same.

Moon earthrise

There is no actual moonrise on the Moon: the same side of the Moon always points towards the earth, and so there is a "far side" of the Moon but not a "dark side." The far side is lit up when the side facing us is dark, or a "New Moon." The orbiter is circling the Moon and so does regularly experience an "earthrise," though it is rare for it to have its cameras pointing in such a way as to capture this event.

Moon earthrise

The animation was stitched together by Phil Plait, who deserves a lot of credit for what must have been a tedious exercise. The animation is mesmerizing and is fun to watch a few times to catch different perspectives.


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