How to explain the rise of Neil deGrasse Tyson? It's hard to deny that we live in an era in which science — as both a worldview and as a practice — is under near-constant assault. On the left, there are those who rail against the dangers of GMOs and vaccines. On the right, there are those who deny climate change and the evolution of species. And across the board, we've seen our nation's competitiveness in the basic academic foundations of science fall ever farther behind our global peers in Europe and Asia.

Given all that, it's amazing that "Cosmos," a big-budget continuation of the late Carl Sagan's classic PBS documentary miniseries exploring the infinite reaches of space and time, is happening at all — and even more so that its debut tonight will be one of the biggest television rollouts in history. It will be simultaneously broadcast to half a billion viewers on over 220 outlets in 181 countries around the world, via channels owned by the Fox network and the National Geographic Channel. (Here in the U.S., where it will air at 9 pm on FOX, National Geographic Channel, FX, FXX, FXM, FOX Sports 1, FOX Sports 2, Nat Geo Wild, Nat Geo Mundo and FOX Life, it will be introduced with a special message by none other than President Barack Obama.)

That's in no small part a testimony to Tyson, the show's new host, the author, astrophysicist and director of the Hayden Planetarium who has effortlessly stepped into his old mentor Sagan's shoes as the most engaging and charismatic science communicator of our time.

Tyson's ability to expound on complex and arcane topics with clarity (and often hilarity) have made him a regular guest on television talk shows, turned his StarTalk Radio podcast into a must-download weekly event, and drawn him a staggering 1.7 million followers on Twitter. And yesterday, in his SXSW keynote at the Austin Convention Center, he had a packed room of over 7,000 geeks eating out of the palm of his hand.

Tyson was nominally being interviewed by Scientific American's Christie Nicholson, but from the get-go Nicholson was primarily holding on for dear life as Tyson rocketed from subject to subject, drawing gales of laughter and appreciative rounds of ovation seemingly at will, and demonstrating why his version of "Cosmos" will be must-see TV.