A 15m wide, 10,000-tonne meteor that packs triple the force of the nuke dropped on Hiroshima is nothing to scoff at. But in the grand scheme of things, the meteor that hit Chelyabinsk, Russia, last week is a cosmological runt. Space rocks as much as 30m across are estimated to strike every 100 years or so and those like the 50m diameter Tunguska meteor of 1908 hit maybe once a century.
Though rare, these "killer asteroids" can wipe out a city the size of Moscow and kill upwards of 30,000 in an instant. But when the University of Hawaii's new meteor-tracking systems come online, we'll be able to forecast meteor strikes as accurately as we do blizzards.
It's known as the ATLAS (Asteroid Terrestrial-impact Last Alert System) and consists of a pair of observatories located about 100km apart, each equipped with four, 10-inch telescopes outfitted with 100-megapixel cameras. Together, these observatories would scan the visible sky twice a night. If an object moves in relation to its previously recorded spot on any given (or subsequent) night, that object is flagged for further investigation. The telescopes, though relatively small, will be sensitive enough to spot and estimate an incoming threat's exact impact location and time, to the second.
According to University of Hawaii astronomer John Tonry, these telescopes are so detailed, they could spot a match flare in NYC from the Golden Gate Bridge.
The project has been kicked around since at least 2010, but it appears that the recent flyby of 2012 DA14 has provided sufficient imperative to jump start the plan's funding with a $US5 million five-year grant by NASA's Near Earth Observation Program. That's enough to build both observatories, develop the necessary software, and staff the program for 48 months.
ATLAS will complement the Institute for Astronomy's Pan-STARRS project, a system that searches for large "killer asteroids" years, decades, and even centuries before impact with Earth. Whereas Pan-STARRS takes a month to complete one sweep of the sky in a deep but narrow survey, ATLAS will search the sky in a closer and wider path to help identify the smaller asteroids that hit Earth much more frequently. The project will take a closer and wider pass at the cosmos than the University of Hawaii's Pan-STARRS telescope array, which takes a month to complete one sweep of the sky in a deep, but narrow, survey.
ATLAS is expected to spot half of the 50m asteroids in the solar system and two-thirds of the 140m planet killers that are thought to be floating around us. This would give people in the impact zone anywhere from a few days to a few weeks to evacuate, depending on the size of the rock. And though the system's detection rate will likely never top 75 per cent, it will coordinate with other space-based comet catchers like the NEO and Pan-STARRS telescopes, which peer further but over a smaller swath of sky, to maximise their coverage.
"We want to put ourselves in the way of discovering the unexpected," Tonry said. As such, the ATLAS should also be able to track more benign astronomical events like supernovas, variable stars, gravity waves, and asteroid impacts out in the Kuiper belt. [Live Science - Space - Falling Star - Space Daily]