Fafnir explains gravity, and some other theories:

General relativity says gravity is caused by the 'curvature of space' which is crazy. Space isn't curved! It's big an black an empty an fulla spaceships! If it was curved how would spaceships fly in it? They would crash into the curves an blow up an stuff! Gravity isn't caused by any crazy 'curved space'! It is caused by scientifical processes such as leprechauns.

Leprechauns are all over the universe grabbin onto matter with their tiny leprechaun hands an holdin it together. hen you walk down the street insteada plummeting into pace it is because leprechauns are holdin you down onto the earth. Of course leprechauns are pretty small so when you jump you break free for a little while until the leprechauns grab you again!

And in the comments, we find facts that support this theory. Such as:

...leprechauns don't swim well, and that's why you feel lighter in water.

Who can dispute it?