Fast forward about 65 million years. A creature much smaller and weaker dominates the Earth now, with brains instead of brawn. Its brain is a lot larger than yours relative to its body size - plenty big enough to conceive a way to scan the cosmos for objects like the colossal asteroid that wrought the end of your kind.
The creature designed and built WISE, NASA's Wide-field Infrared Survey Explorer, to search for "dark" objects in space like brown dwarf stars, vast dust clouds, and your nemesis - asteroids. WISE finds them by sensing their heat in the form of infrared light most other telescopes can't pick up.
"Our instrument is finding hundreds of asteroids every day that were never detected before," says Ned Wright, principal investigator for WISE and a physicist at the University of California in Los Angeles. "WISE is very good at this kind of work."
Visible-light telescopes conducting past asteroid surveys may have missed a large population of darker asteroids that WISE is now flushing out of hiding. Most of the asteroids WISE is finding are in the main asteroid belt between Mars and Jupiter, but a fraction of them are different - they're the kind of Earth-approaching asteroids that send shivers all the way down a Brontosaurus' spine.
"WISE has only been in orbit for about three months, but we've already found a handful of asteroids classified as 'potentially hazardous,' including one seen in 1996 but lost until re-observed by WISE. To be named 'potentially hazardous,' an asteroid has to pass within about 5 million miles of Earth's orbit. One of our discoveries will cross Earth's orbit less than 700,000 miles away."
"WISE actually discovered all five of the NEOs the center was confirming as of March 1st," says Wright.
The asteroid that wiped out the dinosaurs was big--about 6 miles or 10 km in diameter. The chances of a similar hit in modern times are remote, but that doesn't mean we're out of the woods. Smaller asteroids are fairly common, and they can do damage, too. As recently as 1908, for instance, an asteroid some tens of meters across exploded over Tunguska, Russia, wiping out eight hundred square miles of remote forest.
Many telescopes on Earth are already searching. Notable programs include LINEAR, the Catalina Sky Survey, Spacewatch, NEAT and LONEOS, among others. Working together over the years they have found more than a thousand potentially hazardous asteroids.
WISE's contribution to the total will be impressive. Between now and late October, when the mission is slated to end, Wright estimates the observatory will find a hundred thousand asteroids, mostly in the main belt, and hundreds of near Earth objects.
Those are numbers even a Brontosaurus could appreciate.