Short movie of the asteroid 2013 ET tracking across the sky made over a half-hour on March 4, 2013
Like cars on a freeway, they come out of nowhere, blow by and disappear in the distance. Asteroid 2013 EB passed within a moon’s distance of Earth on Feb. 28, while 2013 EC did the same four days later. Both spanned between 40-50 feet across or slightly smaller than the object that lit up Russian skies three weeks ago.
Next up is the heftier 2013 ET which cruises by Earth Saturday morning (6:09 a.m. CST) at a distance of 600,000 miles. That’s about 2 1/2 times the distance of the moon. Astronomers estimate ET’s diameter at 328 feet (100 meters).
None of the earlier flybys posed a threat to Earth and neither will 2013 ET as it diligently follows its path around the sun. You can keep your eyes on the asteroid courtesy of astrophysicist Gianluca Masi and his robotic telescope setup in Italy starting at 1 p.m. (CST) tomorrow March 8. Masi will broadcast the live photos of 2013 ET on WebTV and provide commentary.
All three building-sized rocks were discovered very recently. 2013 ET was spotted on March 3 by the Catalina Sky Survey based in the Catalina Mountains north of Tucson, Arizona. Discoveries like these are almost a daily occurrence and highlight the fact that of the estimated one million small near-Earth asteroids out there, we’ve discovered and tracked only 9,754 as of March 4, 2013. That’s less than 1%.
Of these, 861 have diameters of 1 kilometer (0.6 mile) or larger and 1,379 are classified as potentially hazardous, meaning their orbits take them threatening close to our planet. This doesn’t necessarily mean we’ll be hit, just that the potential exists.
But there’s a silver lining. We’ve already discovered over 90% of the big, kilometer-plus-sized asteroids, greatly reducing the uncertainty of “what’s out there” when it comes to the worst potential impacts. The last really big smack-down of which we’re aware was the impact of a 6-mile-wide asteroid that triggered the mass extinction that wiped out the dinosaurs 65 million years ago. The 110-mile-diameter Chicxulub Crater in the Yucutan Peninsula remains as a testament to this Earth-altering event.