Why won't Minecraft launch?

(Macbook Pro) I have the latest Minecraft launcher. It wasn't launching before, so i created a new user on my computer, and installed mine craft on that. When I click "Start" in the minecraft launcher, the code in the "development console" section says that it's downloading a bunch of stuff. After it says that it finished downloading these things, it says a bunch of code that pretty much says that it failed. Unfortunately, the code takes up too many characters to post it here, so if you want to see what it says, email me: ezrazimmer@gmail.com