Four years ago, a house-sized asteroid tore through the atmosphere over Chelyabinsk, Russia, and exploded. Shock waves shattered windows and knocked down onlookers as fragments of the disintegrating space rock peppered the Ural countryside.
This week an asteroid about the same size is approaching Earth. It will not hit our planet, but it’s coming very close. On Oct. 12, 2017, the speeding space rock, named “2012 TC4,” will skim just above the zone of Earth’s geosynchronous communications satellites and briefly become a target for amateur telescopes.
2012 TC4 measures somewhere between 10 m and 30 m wide, and on Oct. 12th it will pass 27029 miles (43,500 km) above our planet’s surface, about 1/8th the distance to the Moon. The flyby is so close, Earth’s gravity will significantly alter the asteroid’s trajectory before it exits the Earth-Moon system.
“We know the orbit of 2012 TC4 well enough to be absolutely certain that it won’t hit Earth,” says Paul Chodas, manager of the Center for Near-Earth Object Studies (CNEOS) at JPL,”but we haven’t established its exact path just yet.”
To get a better handle on the asteroid’s orbit (and possible future encounters), an international network of telescopes will monitor 2012 TC4 as it goes by. Pinging the asteroid with its Goldstone radar, NASA hopes to learn much about the space rock’s physical properties. The space agency will even exercise some aspects of its planetary defense systems.
This asteroid is too small to see with the naked eye. However, skilled amateur astronomers using 8+ inch telescopes will be able to observe it. At peak brightness, 2012 TC4 will shine like a 13th magnitude star as it zips through the constellations Capricornus and Sagittarius, according to AstroBob, who has detailed observing tips.
Source: NASA’s Spaceweather.com