text: on gravity..? maybe i should have learned this in 3rd grade but here is my question...#1 is everything in the universe held it its specific locations by gravity? if so why do stars  "fall" and not float? #2 will gravitys "lock" on everything eventually weaken or will it remain constant forever?is the reason we can walk on the earth and not the moon because of the shield of the atmosphere? if so will the atmosphere eventually waste away? #1) everything in the universe is affected by gravity but is not held in specific locations. objects are in motion but under the effects of gravity.  #2) gravity is a constant with a few rules to follow: the gravitational force between two objects is directly proportional to their mass but inversely proportional to their distance from each other. this means that object with more mass have more gravitational force but the gravity that they generate is lessened as two object move farther apart from each other.  scientists speculate whether the universe will eventually succumb to the forces of gravity, causing all matter to eventually be pulled back into where the big bang originated, or if the bang was sufficiently powerful, will all of the matter in the celestial bodies in the universe continue moving outward until the distance between the stars is so great that gravity can't overcome it and each galaxy is left to slowly burn out like sparks from a fireworks display?  for the last part of your question, people can walk on the earth and on the moon. the gravitational pull of our moon is a fraction of the earth's pull because the moon is a fraction of the earth's mass (remember the rules in part 1). we can't breathe on the moon because there isn't an atmosphere. the lack of an atmosphere has nothing to do with the moon's size though. it's simply due to the way the moon was formed.  i hope that i was able to explain this to you properly. i'm no scientist.