Its night time on the far side of the moon. On 11 July the China National Space Administration (CNSA) announced it had sent commands to its Chang’e-4 probe on the far side of the moon to go into its dormant state. The lander and the rover will both ‘sleep’ through the 14 day lunar night before they are sent commands to wake up and continue the mission. The lander and rover require sunlight to charge their electrical systems and so can only operate during the moon’s daytime. For the moon to completely rotate on its axis and the sunlight to return, takes approximately 29 days. The nighttime, when there is no sun, and the daytime, when the sun’s light reaches the surface of the far side of the moon, are both approximately 14.5 days. The progress of the lunar days across the surface of the moon can be easily seen from Earth in the changes phases of the moon.
However, as explained in the CNSA 11 July report, “As a result of the tidal locking effect [between the Earth and the Moon], the moon’s revolution cycle is the same as its rotation cycle, and the same side always faces Earth.”
This synchronicity has historically caused the far-side of the moon to remain unseen and a mystery (1). That is until the early days of humanity’s first tentative steps into space. In October 1959 a lunar probe, Luna 3, launched by the Soviet Union, sent back pictures of the far side of the moon. The first humans to see the far side of the moon were the American astronauts in Apollo 8 as they orbited the moon (10 times) in December 1968.
There is still a great deal to discover about the moon, both on the far side and on the side that faces the earth. The return of the sun, and the return of the Chang’e-4 probe to its mission, may enable further discoveries and help humanity to heighten the potential of humanity’s return to the moon – and to go beyond.
The pictures at the top include (upper) a picture from the current Chinese mission on the moon, and two pictures (lower) from Apollo 8.
The link to the Change-4 mission: http://www.cnsa.gov.cn/english/n6465719/c6806820/content.html
Apollo 8 mission: https://solarsystem.nasa.gov/missions/apollo-8/in-depth/
(1) Lil Wayne’s song “Dark Side of the Moon” – with Nicki Minaj – speaks to the mystery of the far side of the moon. – “On the dark side of the moon
I’ll be waiting, I’ll be waiting for you
On the dark side of the moon
And If you happen to get there before me
Leave a message in the dust just for me
If I don’t see it I’ll be waiting for you
On the dark side of the moon (yeah, yeah, yeah, yeah)” (Lyrics copied from https://www.azlyrics.com/lyrics/lilwayne/darksideofthemoon.html .)