The punchline is obvious, but for those of you wondering about the details (and not feeling like wasting time googling things):
Dan Quayle was the VP of the United States between 1989 and 1993.“Carson” was The Tonight Show Starring Johnny Carson, which aired between 1962 and 1992.
It’s basically a science-y way of saying “something improbable happened and hell didn’t froze over”, with “hell” replaced with “Earth’s core”. The “something improbable” in question is the Apple 4-button mouse.
The punchline is obvious, but for those of you wondering about the details (and not feeling like wasting time googling things):
Dan Quayle was the VP of the United States between 1989 and 1993.“Carson” was The Tonight Show Starring Johnny Carson, which aired between 1962 and 1992.
And the strip came out in 2006, natch.