You mean low gravity right? Because anti-gravity is impossible in Minecraft (at least, smoothly) and the moon still has 1.6 ms/s^2 gravity. (Earth has 9.8 ms/s^2. But a moon map = Epicz
There is a command block method of doing zero gravity, but I would probably have minor gravity as SAFollis said...
I like the effect of Jump Boost II and Slowness I...
Minecraft can do anti-gravity (not very well but possible, and only singleplayer) while zero gravity isn't realistically possible without a mod/plugin. If it is possible please show me how.