Neil deGrasse Tyson looks kind of defensive. Or possibly confused. Or is he dismissive?

In a newly-minted internet meme, a four-second animated GIF captures the famous astrophysicist tossing up his hands and rolling his eyes. A still version of the gesture -- pursed lips, exposed palms and all -- has also been widely circulated as a black-and-white drawing. This depiction is sometimes accompanied by the words, Watch out guys, we're dealing with a badass over here, and is posted in online forums to mock anyone who gets too cocky.

It all began in June of last year, when a video of Tyson discussing Isaac Newton was uploaded onto YouTube. A minute and a half into the video (below), Tyson mentions that Newton invented his own kind of calculus before turning 26. And then he makes the gesture -- a nonverbally sarcastic 'no big deal' of sorts -- that is now exploding all over Reddit and other social networking sites.

There's another reason Tyson is all over the place these days: he's been making the media rounds to promote his latest book: Space Chronicles: Facing the Ultimate Frontier. In it, he outlines the reasons why we ought to pursue space exploration.

In an interview with NPR on Monday, he explained his idea. Venus has a runaway greenhouse effect; I kind of want to know what happened there. Mars once had running water; it's bone dry today. Something bad happened there as well. Asteroids have us in [their] sights. Dinosaurs didn't have a space program, and they're not here to talk about this problem. We are, and we have the power to do something.

That kind of accessible, impassioned speech is what has made Tyson so popular -- even before the big meme. He's a frequent guest on television news outlets like CBS, MSNBC and PBS. He is a scientist, author, lecturer, and the director of the famous Hayden Planetarium at the American Museum of Natural History. He's an expert on everything from exploding stars to dwarf galaxies to fine wines, and he was the guy behind the movement to downgrade Pluto from a planet to a dwarf planet.

Tyson was born in New York City and studied physics at both Harvard and Columbia University. Today, he lives in Manhattan with his wife and two children. His immediate goal is to promote his book so that readers recognize the importance of scientific literacy.

Space exploration is hard. It takes great investments, he said in an interview with the Huffington Post. My goal here is to get people to recognize that when nations dream big, its citizenry dreams big. And the dreaming big part is what makes tomorrow come.