Jor-el knows time travel...

[jesustlife]

Jor-el helped Clark go back in time to save Lana in the 100th episode, remember? He used a crystal, though he said it could only be used once, that doesn't mean there are hundreds of those crystals that can be used once too.

[Kal el of krypton]

yes it probably does mean krypton found the technology on time travel and brainiac found out a way to use it too. And most likely clark isn't going to time travel back to krypton.