Did You See That?

You know how you’re zipping down a two-lane road admiring the countryside and suddenly here comes a truck--a rather large truck--that blasts past with a car-rocking THRUMP that makes a teenage passenger say, “Cool!”? Well, planet Earth had one of those close encounters the other day with a very large, gray galactic rock, and most of us remain clueless.

While we’re down here obsessing about important stuff like football playoffs, Sen. Joseph Lieberman’s Afghanistan trip and mounting LAX parking fees, a rock the size of two Rose Bowls blew across our planet’s bow at 68,000 miles an hour. This lifeless chunk of primordial refuse has been tumbling around the sun on its own wobbly orbit every 1,321 Earth days since the solar system was formed 4.5 billion years ago. And we just now nearly met up with it.

This encounter didn’t merit 15 seconds of network fame because it was 510,000 miles away--twice the moon’s distance, but a very near miss in cosmic terms. Earth itself moves through 18.9 miles of space every second (66,500 miles an hour), never transiting the same spot twice. Change Earth’s position a tad and a good bit of Europe could be gone today, or a colossal splash would have gained the attention of countless coastal cities.

Now, here’s the real catch: No one on Earth saw this stony rogue coming. Not until the day after Christmas when an automated NASA telescope in Maui detected the approaching asteroid’s faint movement and alerted the Jet Propulsion Laboratory’s Near Earth Objects Office in Pasadena.

Named 2001 YB5, the rock joins thousands of tracked space objects, 564 of them over a kilometer across. Hundreds more mammoths remain out there unknown. Not that advance notice would help; there’s currently no defense for asteroid collisions, not even a Bruce Willis. And now the Tora Bora caves are gone too.

On Tuesday, there will another fly-by of a gigantic rock, when 4660 Nereus blows through the neighborhood. Being 2.7 million miles away, it’ll be ignored too. Back to movie stars.