How dangerous are near-Earth asteroids? 5 key questions answered.

On Feb. 15, asteroid 2012 DA14, discovered a year ago, cleared Earth by a scant 17,200 miles. The same day, a smaller, unrelated asteroid that no one saw coming exploded 12 to 15 miles above Russia’s Chelyabinsk region. Events that day highlight the risk that near-Earth objects (NEOs) can pose – although to some extent, humans can counter them.

3. What's being done to improve detection?

The vast majority of detections have come from US efforts. Three US ground-based telescope projects are now operating: LINEAR (Lincoln Near Earth Asteroid Research), the Catalina Sky Survey, and Pan-STARRS (Panoramic Survey Telescope & Rapid Response System). The newest is Pan-STARRS, led by the University of Hawaii. The school is also setting up a network of smaller telescopes, dubbed ATLAS (Asteroid Terrestrial-impact Last Alert System), for quick scans of the sky each night.

A future possibility: infrared space telescopes dedicated to searching for NEOs. Infrared wavelengths are better suited for spotting NEOs that are too dim for visual telescopes to pick up. If funded, these telescopes could be launched toward the end of this decade.

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