About:

• The piece of space junk was is the third-stage booster of Chang'e 5-T1 – a lunar mission launched by the China National Space Administration in 2014.
  
  
• The object reportedly weighs around four tonnes and was racing towards the moon at a speed of 9,300 km an hour.
  
  
• This is the first recorded unintentional case of space junk hitting the moon.
  
  

Project Pluto

• American astronomer Bill Gray, who runs a blog called Project Pluto, predicted the collision by tracking the object. The speed, trajectory, and time of impact were calculated using earth-based telescope observations.
  
  
• Project Pluto also supplies astronomical software to amateur and professional astronomers. Gray is the creator of popular astronomy software called Guide.
  
  

Is the crater permanent?

• Both the earth and the moon have been hit by multiple objects like asteroids throughout their existence, but craters on the moon are of a more permanent nature than those on earth.
  
  
• This is because of processes like erosion, tectonics, and volcanism. These three processes keep the surface of the earth crater-free and remove traces of collisions that have happened in the past.
  
  
• An absence of atmosphere means there is no wind system and no weather on the moon, and hence no cause for erosion of existing craters. Absence of tectonics prevents the moon’s surface from forming new rocks, or causing a shift in the existing surface patterns, unlike that on earth.
  
  
• Lastly, absence of volcanism makes it impossible for craters to be covered.
  
  
• Currently, the earth has less than 200 known craters while the moon has thousands.