I have never fully grasped the meaning of the monolith that wakes up that tribe of sleeping apes at the beginning of Stanley Kubrick's 2001: A Space Odyssey. Sure, it was the dawn of man, a symbol of something powerful and futuristic and foreign. But, huh? Well, a few weeks ago it was my fate to sit at dinner next to a geologist who is obsessed with extraterrestrial life. She explained that she and her colleagues had been bombarding the cosmos with messages, all sent purposefully into the void. "This represents a transition in the history of evolution," she told me. "It's like planting Kubrick's monolith: The technology will be waiting when the tribe becomes ready to use it."

Ahh, so that's it. But what, these days, could pass for the monolith? Computers, smartphones, iPods, many megapixel digital cameras—boring. Fast cars and supersonic transport? Forget it. Even among the jet set, the imperative for carbon neutrality is transforming Bentley and Gulfstream into four-letter words. No, my vote would have to go to the high-definition flat-screen television. They take up no space, consume little energy, and can turn people who don't even like television—me, for instance—into drooling couch potatoes content to spend hours watching reruns of Miami Vice, documentaries about mollusks, and pretty much anything else. Still, if you can buy one of these miracle boxes at Wal-Mart, can the flat screen truly be considered a modern-day monolith?