How bad are things on planet Earth? So dire that a coalition of alien civilizations has sent Keanu Reeves down from outer space to destroy the human race, thereby saving our threatened environment. At least that's the plan in this update of the 1951 sci-fi classic The Day the Earth Stood Still, which substitutes hostility toward the natural world for the Cold War's promise of mutually assured destruction.

Earthlings will likely turn out in droves since film buffs of all ages want to see whether their species will be annihilated; and the competent effort is a distraction from the economy and other pressing problems, including, ironically, the damage we're doing to the environment.

In Robert Wise's original, based on the Harry Bates short story "Farewell to the Master," a lone spaceship landed in Washington, D.C. In the remake, a big spherical snow globe descends upon New York's Central Park and disgorges a being covered in whale blubber that quickly comes to resemble the mountain climber whose 1928 Himalayan encounter with a much smaller orb comprises the movie's prologue.

He calls himself Klaatu -- though he's really Neo without the sunglasses (or Spock minus Kirk) -- and he wants to reason with folks at the United Nations in an eleventh-hour attempt to convince us to change our ways. He's accompanied by a large protector robot that could have been modeled subconsciously (and hopelessly) on a platinum Oscar statue. Soon known by the acronym GORT, it ends up at a secret U.S. military facility, while Klaatu is taken to a makeshift hospital and placed in the care of a klatch of scientists hurriedly assembled by the government.

For story if not scientific purposes, the most important of these is Princeton astrobiologist Dr. Helen Benson (Jennifer Connelly). One minute she's at home trying to get her stepson Jacob (Jaden Smith) to eat a solid meal, the next she's conversing with an expressionless alien who says he's going to wipe out mankind. While she bonds with Klaatu, the no-nonsense Secretary of Defense (Kathy Bates) arrives and orders the extraterrestrial detained and interrogated. Benson agrees to help him escape -- even though he's made no bones about the nature of his mission.

Klaatu gets away. He has powers, after all. But he also has the temerity to eat a tuna fish sandwich from a vending machine in Newark's Penn Station and so falls ill. Benson collects him and, together with Jacob, they go on the lam in the Garden State. Meanwhile, there's mass panic because smaller alien orbs have landed in spots throughout the world.

The first stop for our trio is a McDonalds where Klaatu converses in Mandarin with a fellow ET. Then they drop in on Benson's Nobel-Prize-winning mentor (John Cleese). The Bach piping through the professor's house and his keen insight into human psychology add to Klaatu's growing doubts about whether extermination is the best course of action. Mind you, the aliens' plan has already been set in motion and any attempt to fight it will only make it stronger. Yet it's not beyond the realm of possibility that Klaatu can derail the apocalyptic mechanism. A cogent argument for saving the human race isn't made, although what he witnesses proves to be enough. Turns out this cosmic robot of death is a pushover.

As the movie progresses, Reeves sounds like he's trying to mimic Rod Serling. You'd think his normal speaking voice would do just fine. In his first big-budget picture, Scott Derrickson (The Exorcism of Emily Rose) demonstrates he's an efficient overseer of spectacle. The sequence inside the military's Flash Chamber where GORT is held stands out. If I'm not mistaken, the key special effect was first employed in 1999's The Mummy, and NFL fans will take notice when Giants Stadium in the New Jersey Meadowlands becomes one of its victims.

There's very little fat on David Scarpa's screenplay. It helps that our defiling of the planet has now become a movie cliché. No explanation is necessary and no gross examples of our polluting, wasteful behavior need be shown. "The pain will only last a moment," Klaatu tells a Jersey cop before crushing him between two cars (and then healing him). Sci-fi aficionados and purist fans of the first The Day the Earth Stood Still will probably experience more than a moment's worth of discomfort, but this remake is not horrible. And since they'll have to see for themselves, it could become a hit. 

(Released by Twentieth Century-Fox Film Corporation and rated "PG-13" for some sci-fi disaster images and violence.)