After all the excitement last week Friday when Earth had an encounter with two space rocks, one lies in countless fragments in the frozen Ural Mountains in Russia while the other is heading intact out into interplanetary space. (Related pictures: “Meteorite Hits Russia.”)
NASA unveiled a new 72 frame movie using the 230 foot (70 meters) Deep Space Network antenna at Goldstone, California of the building size asteroid DA14 as it swung by Earth on Feb.15 and 16. This now represents our first imagery of what this cosmic interloper actually looks like.
The grainy images were taken only hours after its record-setting approach, zipping by at only 17,200 miles (27,000 km) from Earth’s surface – passing even closer than orbiting communication satellites. (Related: “Watch Asteroid Buzz Earth.”)
The short video spans 8 hours and shows a 130 foot (40 meter) long object as it speeds away, increasing its distance from Earth from 74,000 miles (120,000 km) to 195,000 miles (314,000 km). The new size is 5 meters shorter than estimates before Friday’s encounter. Unfortunately we don’t get to see too much detail as the resolution is only about 13 feet (4 meters) per pixel, but the movie clearly shows the asteroid is tumbling.
NASA researchers hope to continue collecting more radar images this week so as to get a precise handle on the asteroids orbit as well as its physical characteristics. Already they know that the gravitational encounter with Earth has tweaked the asteroid’s orbit such that it will not make such close approaches with Earth for at last the next century.
If DA 14 would have impacted our planet – the local devastation would have been quite impressive – on the scale of Siberia’s Tunguska event in 1908. Scientists speculate that a small office building sized rock slammed into the atmosphere and exploded above the remote forested area more than a century ago – with the force of 180 atomic bombs dropped on Hiroshima during World War 2. (See “Russian Meteorite Spotlights History’s Other Crashes.”)
The resulting air blast scorched the land, flattening trees for 820 square mile (1300 square km) area. Seismic shock-waves were registered in London, England and reports say night skies glowed as far away as Asia.
Last week’s 55 foot (17 meter) wide Russian meteor now ranks as the most powerful meteoric event since Tunguska.
So while meteorite hunters scour the Chelyabinsk region for remnants left behind by that atomic-bomb scale explosion of a space rock, let’s count ourselves lucky that DA14 just brushed past. (Related video: “Predicting Meteorite Impacts.”)