Hi Michelle, The meaning of the sentence is that the gravitational pull (attraction) of Earth keeps the Moon in orbit around Earth (going around Earth). "Go off" means move in another uncontrolled direction, so the Earth keeps the Moon under control and stops it flying away into space. "Go off" is a very common phrasal verb with a lot of different meanings. It can mean loss of control: John went off at his teacher after he failed his exam - John shouted at his teacher uncontrollably. He went off on a tangent during his presentation - He started talking about an unrelated topic during his speech. His gun went off - He fired/shot his gun unexpectedly. We use it when an alarm or siren starts making a noise: I set my alarm for 7.30 every morning. It makes a loud noise when it goes off. - My alarm starts ringing loudly at 7.30 in the morning. It can mean "to happen:" The event went off without a hitch - the event took place, and there were no problems ("without a hitch") It can also mean to stop liking someone or something: The French have gone off Emmanuel Macron since he was elected - Macron isn't as popular anymore. It can also mean to start rotting or lose freshness. The milk has gone off - The milk is sour and we can't drink it anymore because it's not fresh. Hope this helps!

there is a power of gravity between both the earth and the moon which do not let the moon go away in a straight line going off means go away .. btw it is attraction not attaction

....from going off (it's usual path, and then going) in a straight line. "Going off" can mean going in an unexpected direction.