On February 15, 2013 an asteroid about half the size of a football field will pass by the Earth with only 17,200 miles to spare. The asteroid, named 2012 DA14, will pass Earth closer than many man-made satellites. Don Yeomans of NASA’s Near Earth Object Program at JPL told reporters:
“This is a record-setting close approach. Since regular sky surveys began in the 1990s, we’ve never seen an object this big get so close to Earth.”
As it threads the gap “between low-Earth orbit, where the ISS and many Earth observation satellites are located, and the higher belt of geosynchronous satellites, which provide weather data and telecommunications”, NASA will use the opportunity to carefully study the flyby to glean data that could help them eliminate any future asteroid(s) that poses a threat to planet Earth. NASA’s Goldstone radar in the Mojave Desert is scheduled to ping 2012 DA14 (which is made mostly of stone and measures 50 meters wide) almost every day from Feb. 16th through 20th. The echoes will not only pinpoint the orbit of the asteroid, allowing researchers to better predict future encounters, but also reveal physical characteristics such as size, spin, and reflectivity.
NASA thinks the chances of the asteroid hitting Earth are remote, however, NASA reminded the public of the Tunguska Event.
“In 1908, something about the size of 2012 DA14 exploded in the atmosphere above Siberia, leveling hundreds of square miles of forest. Researchers are still studying the “Tunguska Event” for clues to the impacting object.”
During the hours around its closest approach, the asteroid will brighten until it resembles a star of 8th magnitude (6th magnitude is the limit of the naked eye – Neptune is an example of a magnitude 8 object). Theoretically, that’s an easy target for backyard telescopes. The problem will be the speed of the asteroid. The asteroid will be racing across the sky, moving almost a full degree (or twice the width of a full Moon) every minute. That’s going to be hard to track with an amateur telescope.