Why we don't see the dark side of the Moon

 

as planet earth spins on its axis  we only ever see the one side of the  moon  almost as if it's a 2d cardboard cutout  hanging in the night sky  so why don't we ever see the dark side  of the moon and no  we don't mean the pink floyd album  welcome to fact nominal  and we're getting into the science of  why we don't see  the dark side of the moon the first  thing to understand about the dark side  of the moon is that it isn't really  well dark it gets plenty of sunlight  just like the blue marble we're sitting  on right now  the only reason it's called the dark  side of the moon is because it's  impossible to see it for us  well that was the case until 1959  when the soviet luna 3 spacecraft gave  us a permanent photograph of  what this mysterious area actually  looked like  it wasn't until 1968 when the apollo 8  astronauts became the first humans to  ever see the far side of the moon in  person  what's interesting is that until january  3rd  2019 all landings on the moon actually  took place on the near side  the cycle being broken by the chang iv  spacecraft  so then why can't we see it according to  john keller  the deputy project scientist for nasa's  lunar reconnaissance orbiter project  the moon does rotate but it rotates at  the same speed as it rotates around the  earth  this means that in practical terms the  moon is tidally  locked to the earth in the time it takes  to completely orbit the earth one time  the moon makes a complete rotation  around its own axis thus  meaning that the same side is facing us  24 7.  the moon has a natural tendency to spin  faster however it's the  gravitational field of the earth that  keeps it in place  and in a tidal lock think about it like  how a car tends to drift when it turns  on a curve  the friction of the road stops it from  drifting further  this seems a bit too convenient right i  mean for the moon to be  in a perfect tidal lock it would have to  be the exact right shape in order for  earth's gravity to act in the specific  way that we observe it to  well it turns out the moon wasn't always  the same shape we see it today  a long time ago scientists believe the  moon had its own  spin and over a long long period of time  frictional forces including the  gravitational field of the earth  actually molded the moon into a more  spherical shape  however the moon isn't exactly a perfect  sphere  if it were then the far side and the  near side would both  experience the same effect of earth's  gravity and would hence cancel out  since it isn't a perfect sphere what  ends up happening is that  a similar portion moves toward the earth  as it spins  while a larger portion moves away since  the resulting distribution of gravity is  uneven  a torque is created that springs the  moon back into place  this motion is referred to as lunar  libration  and it also explains why the size of the  moon appears to change over time  in fact due to libration about 59 of the  moon's surface is seen over time  due to a perceived wagging effect that  ends up  showing more than just one hemisphere in  fact  libration allowed early astronomers to  actually identify a land feature of the  far side of the moon  in 1906 julius franz identified what he  called  the mere oriental a prominent impact  basin that spans almost 1 000 kilometers  the far side and the near side differ  more than just their names however  more recent images of the far side from  missions such as the lunar  reconnaissance orbiter  have revealed to us the exact nature of  the far side of the moon  and how it actually differs from the  side we've gotten so used to seeing  for one the far side is actually older  in a sense  it's a widely held belief that the moon  was molten when it first formed  later cooling down to a more solid state  it seems that the far side actually  cooled down first meaning  it has more craters as a result the far  side has far  less maria planes on the moon that early  astronomers incorrectly thought were  seas of lunar water  the far side has only one percent of its  surface covered by this maria  while the near side has around 31  a strange phenomenon that the lunar  reconnaissance orbiter team have noticed  is that  the near side of the moon seems to have  more radiation than the far  side which can easily explain why it  took so long for it to cool down  however the team doesn't have any idea  what could have caused this bias  for one reason or another one side was  favored over the other  other popular theories have been  proposed that seek to understand the  differences between the two sides  one such theory suggests that the moon  once collided with a smaller companion  moon  explaining the size difference between  the two sides  however analyses of this far side of the  moon suggest  that no collision ever happened and that  the size and terrain differences  simply develop naturally new research  has proposed that the crust on the far  side is much thicker than the near side  meteorite impacts would thus have a  stronger effect on the near side  that would create maria while the  thick-skinned far side  would simply brush the impacts off as a  flesh wound  there is still much to be understood  about the origins of the moon and the  exact differences between  the hemispheres which side of the moon  would you prefer to live on  the rocky crater as far side or the flat  smooth nearside let us know in the  comments below  if you enjoyed this article and want to  make sure you never miss another one of  our space articles  make sure to leave a like and subscribe  to our channel  who knows what you'll learn next