Thread by @ikluft

“Earthrise: A Video Reconstruction” is #NASA #astronomy picture of the day by @apod/@USRAedu apod.nasa.gov/apod/ap181223.… Apollo 8’s iconic photo “Earthrise” was taken 50 years ago; 4K HD animation shows astronauts’ view using NASA LRO data of lunar surface

“Earthrise in 4K” is a 50th anniversary commemoration of the 1968 #Earthrise image during Apollo 8, and description how the rendering was made with NASA LRO imagery/data taken since 2009, by @NASA/@NASAGoddard/@USRAedu #astronomy #Apollo50 #Apollo8 #Moon

#Apollo8 was historic for 1st time humans left Earth and orbited the Moon. Apollo was intended as Cold War competition with Soviets. Starting with #Earthrise photo and many other observations, we found we had much to learn about Earth there. #astronomy #space #history

Example of what we learned about Earth from going to the Moon: lunar rocks have the same isotopes as Earth. This means the Moon came from material in the Earth, not as a separately-formed solar system body captured into Earth orbit. Led to “Giant Impact” theory. #space #astronomy

Example of what we learned about Earth from going to the Moon: lunar surface geology is primarily driven by asteroid impacts, not volcanoes as originally thought. Earth & Moon are in same space together: upon further study we realized Earth has impact craters too. #space #geology

The scientific learning process probably couldn’t have gone in any other order than noticing we needed to search for hazardous Earth-crossing asteroids until after we had been to the Moon and learned about impacts there. #Apollo50 #astronomy #asteroid #LowFlyingRocks

"We came all this way to explore the Moon, and the most important thing is that we discovered the Earth." - #Apollo8 astronaut Bill Anders (who took the famous #Earthrise photo) #Apollo50 #NASA #space #history