The Apollo 10 crew are also the humans who have traveled the farthest away from home, some 408,950 kilometers (220,820 nmi) from their homes and families in Houston. While most Apollo missions orbited the Moon at the same 111 kilometers (60 nmi) from the lunar surface, the distance between the Earth and Moon varies by about 43,000 kilometers (23,000 nmi), between perigee and apogee, throughout each lunar month, and the Earth’s rotation makes the distance to Houston vary by another 12,000 kilometers (6,500 nmi) each day. The Apollo 10 crew reached the farthest point in their orbit around the far side of the Moon at about the same time Earth’s rotation put Houston nearly a full Earth diameter away.
The existence of ample amounts of hydrogen in the subsurface ocean of Enceladus indicates that microbes--if any exist there--could use it to obtain energy by mixing with carbon dioxide dissolved in water. This particular chemical reaction, termed methanogenesis, because it manufactures methane as a byproduct, may have been of critical importance in the emergence of life on our planet.
Solving A Lunar Mystery Almost As Old As The Moon Itself! The rectangular pattern, with its straight sides and angular corners, weakens the theory that Procellarum is an old impact basin. This is because such a mighty impact would form a circular basin. Instead, the recent study indicates that processes occurring deep beneath the lunar surface dominated the formation of this unique region.
"We don't know how long the Dagwood-sandwich structure would exist. This structure represents a stable state, but various factors could mean the moon doesn't reach this stable state," Dr. Christophe Sotin said in a May 1, 2014 statement. Dr. Sotin is of the JPL.