On Wednesday, Neil deGrasse Tyson appeared on The Nightly Show with Larry Wilmore to deliver what looks to be the final, most decisive blow in his beef with Atlanta rapper B.o.B.

To recap: B.o.B took to Twitter on Monday to profess his belief that the Earth is flat. As you might recall from school, the Earth is not flat, but round. Nevertheless, the misinformed performer of such awesomely bad hits as “Nothin’ on You” and “Airplanes” posted a ton of tweets that more or less argued humans can’t see the curve of a round Earth because the planet is not really round.

Astrophysicist, Cosmos host, and science cheerleader Neil deGrasse Tyson wasn’t having it. He told B.o.B over Twitter that he was mistaken — the world really is round, and B.o.B is not able to see the curve because he’s really small and the Earth is really big.

That’s when B.o.B decided to release a diss track calling out Tyson for being part of a NASA-led conspiracy that’s promoting lies about the Earth’s shape (and also lending support to Holocaust denier David Irving, because why the hell not).

Then Tyson clapped back and released his own diss track performed by his nephew Steve. It is weak.

So Tyson, given a chance to redeem himself, went on The Nightly Show and went in for the kill. The whole thing is chock-full of great lines, but Tyson’s most memorable comes after recalling the great Isaac Newton quote:

“If I have seen further it is by standing on the shoulders of giants.”

Tyson follows up:

“That’s right, Bo.B, when you stand on the shoulders of those who came before, you might just see far enough to realize the Earth isn’t fucking flat.”

And then he dropped the mic.

Round three goes to Tyson.