THE SOLAR SYSTEM Dynamics group of NASA’s Jet Propulsion Lab is, as physicist Marina Brozovic explains, is like “flight control for the solar system.” Basically, it’s the best line of defense between you and the flaming chunks of space rock hurtling toward Earth pretty much all the time. Even though major collisions might seem like something that only affects the distant past or remote areas—a headache for T-Rexes and Russians, but not you—the fact that more population centers haven’t been in harm’s way so far is basically down to random chance.
The reality is that there are millions of near-earth objects swirling out there right now, and we don’t even know where most of them are. But if you feel your blood pressure spiking, take heart: Watcher of the Unseen, directed by Academy Award nominee Keven McAlester, shows that we are in good hands.
“Anything that moves, we want to know the orbit of it,” Brozovic says. Brozovic grew up in Split, Croatia, where she was inspired by Carl Sagan’s groundbreaking (and still relevant) miniseries, Cosmos, and became fascinated with understanding the fine details of the solar system.
Those fine details are now her main gig. There are an enormous number—on the order of billions—of objects between Mars and Jupiter, that sometimes get “nudged” out of their usual path and come rocketing into the inner solar system. When they do, they officially become the Jet Propulsion Lab’s problem: Congress has tasked the group with finding all the near-Earth asteroids with a diameter of more than one kilometer. Brozovic estimates they have identified 95 percent them.
Trouble is, it would only take an impact of something with a diameter of about 50 meters to level a city. For context, the asteroid that gave the Russian city of Chelyabinsk so much trouble didn’t even hit the ground (it exploded at about 97,000 feet in the air, with a force “20 to 30 times greater than that of the nuclear bomb that destroyed Hiroshima”).
Asteroid impacts, even those much smaller than the 10 kilometer dino killer that hit the Yucatan peninsula 66 million years ago, have fundamentally altered the history of life on Earth. In addition to being crazy portents of doom, they have brought organic material and maybe even waterto the Earth’s surface.
“It’s kind of our responsibility as a species to understand the risk involved,” Brozovic says, and she’s right. Fortunately for us, NASA is on it and we’d likely have years to prepare for a major collision, in all likelihood time enough to launch a deflection mission to knock the asteroid off it’s deadly course.
“There is no greater gift that NASA … can give the world then to know the time and place of an [asteroid] impact, and prepare a response,” said Rob Landis of NASA’s Planetary Defense Coordination Office. And while we’re still very much in a phase that Landis calls “doing our homework”—essentially, making a detailed survey of near Earth objects—he was quick to point out that no one is tracking an inbound asteroid at this time and that our atmosphere provides ample protection from almost everything coming our way.
Still, you might want to keep an eye on the sky on March 5th, when asteroid 2013 TX68 is due to make a (relatively) close flyby.
source: wired.com by