"Life Beyond Earth," the two-hour documentary that airs tonight on PBS, raises the big cosmic questions of the ages: Is there life on other planets? If so, is it intelligent life? And why do all these space-related documentaries have eerie, ethereal New Age soundtracks? Isn't it possible that the music of the spheres is punk rock? Or maybe a rousing version of the "Beer Barrel Polka"?

Those are tough questions to answer and it will surprise no one that this documentary--which airs on WETA at 9 and Maryland Public Television at 8--can't answer them. Nobody knows if there's life beyond Earth, not even Timothy Ferris, the award-winning author of "Coming of Age in the Milky Way," who wrote and stars in this show.

"There are more stars in the universe than there are grains of sand on the beach," Ferris says, and he strongly suggests that around at least one more of those stars orbits a planet with something living on it. Whether it's something we'll ever meet--or want to--is another question that's impossible to answer.

Ferris does his best to keep this science lesson lively but it's not easy. He's dealing with complex, abstract ideas in a medium that's more conducive to visual extravaganzas--professional wrestling, for instance.

The trick is to illustrate the abstract ideas with compelling pictures, and Ferris and producer Linda Feferman are willing to try almost anything to pull it off. They rented a helicopter to shoot some glorious footage of volcanoes erupting and porpoises jumping. They created some cool computer graphics of planets swirling through space. And they got some film of pulsing cells and swirling multicolored shapes that will remind viewers of a certain age of the light shows that played behind psychedelic rock bands at the Fillmore East.

In fact, viewers prone to acid flashbacks might want to lay in an extra supply of Thorazine before watching this show.

The producers have also gathered clips from sci-fi movies that show how we humans have imagined extraterrestrial life. One of them is a hilarious Russian movie that shows an earthling astronaut being attacked by a snake on Venus. Even funnier is a newsreel clip of an American describing the aliens he says he encountered in the 1950s: "These ladies were brunettes with dark skirts and medium-heeled shoes."

Ferris is not above hamming it up if it'll help get his point across. He squats beside a campfire in the desert and draws pictures of the solar system in the sand. He dons a helmet, climbs into a racing car and zooms across the Bonneville Salt Flats to illustrate the vast stretches of time in the history of the universe.

In one memorable scene, Ferris appears in a tuxedo, puts some champagne on ice and sits down to wait for a lobster to crawl onto his plate. It's his theatrical way of dismissing Fermi's Paradox, which asks the question: If there are aliens out there, why haven't they shown up yet? No lobster shows up either, Ferris points out, but that doesn't mean that lobsters don't exist.

"I have failed to take the lobster's preference into account," Ferris says archly.

Watching Ferris, you can't help but recall Carl Sagan, who covered much of this same intellectual ground in "Cosmos," his famous 13-part 1980 PBS series. Indeed, this show is dedicated to Sagan, who died in 1996.

But Sagan was a far more animated and upbeat performer than Ferris, who tends, alas, to drone on in a monotone. A recent biography revealed that Sagan was an avid pot smoker, which might explain that gleam he got in his eyes when he uttered (or, it's said, never uttered) the phrase "billions and billions." Perhaps Ferris should have . . . no, that would be wrong.

CAPTION: Timothy Ferris with the Porsche he drives across the Utah desert in "Life Beyond Earth."