August 18, 2019

Astro-Vid Of the Week: Remembering Earthrise

Earthrise as seen by the crew of Apollo 8. (Credit: NASA).

By now, you’ve seen the video.

45 years ago today on Christmas Eve 1968, Apollo 8 astronauts snapped one of the most iconic images of the 20th century as they became the first humans to witness the Earth rise over the limb of the Moon. To mark the anniversary, NASA recently released a short documentary of the fascinating back story to the image, combining simulations and imagery from the Lunar Reconnaissance Orbiter. Modern images were compared to those taken by Apollo 8 to get the position and orientation of the spacecraft in orbit around the Moon just right;

It’s fascinating to watch the perspective of the spacecraft change as we listen to the banter of the excited Apollo 8 crew scrambling to “get the shot”. Earthrise had happened several times previous on the mission, but it was only because of the roll maneuver in progress that it finally became visible. Keep in mind, you can only see a traditional “Earthrise” from lunar orbit or from the poles of the Moon due to libration… this is because the Moon is tidally locked and keeps one face turned perpetually towards the Earth.

It’s also worth noting that the phase we see of the Moon from the Earth is opposite from what the astronauts saw; this means that the Moon would’ve been a waxing crescent, compared to the Earth’s waning gibbous phase.

This new look at “Earthrise” 45 years later was a great early Christmas present from NASA… enjoy this new look at our home planet, and Merry Christmas!

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