why is there only gravity on the moon?

Question: why is there only gravity on the moon?
- Keywords:
  gravity,
  moon,
  space
Asked by Heary to Áine on 18 Nov 2014.
- Áine Broderick answered on 18 Nov 2014:
  
  There is gravity on the moon, The moon is 1/4 the size of Earth, so the moon’s gravity is much less than the earth’s gravity, 83.3% (or 5/6) less to be exact.

Question: why is there only gravity on the moon?