What's the movie called about a guy getting smart?

I don't remember so much of what the movie was really about, but it's
a guy who's celebrating his birthday with some friends. On his way
home he sees some kind of extra terrestrial or UFO in the sky. Next
morning when he wakes up, he's really smart and starts reading books
very fast. He started doing some work in his garden when he invented
some kind of fertilizer.

That's pretty much all I remember from the movie. I don't know what
year it was made, but the guy might have been played by John Travolta.