miércoles, 27 de febrero de 2013

What exploded over Russia? Watch two videos with new answers

Two videos present the latest results – as of February 26, 2013 – on the meteor that exploded over Russia on February 15.

Less than two weeks ago – on Friday, February 15, 2013 – an asteroid exploded over Russia’s Ural mountains. The explosion, which occurred some 8-12 miles (14-20 kilometers) above ground, shattered windows in and around the city of Chelyabinsk, Russia and caused some 1,000 injuries, but thankfully no deaths. Scientists are now saying it was the most powerful meteor explosion in Earth’s atmosphere since the Tunguska event in 1908. Since that day, progress has been made in understanding the origin and make-up of the February 15 meteor explosion. Two new videos present some of the latest information. Both videos were just released; you’ll find them below. The more comprehensive of the two videos is the latest NASA ScienceCast. It’s just under four minutes long and presents NASA scientists’ latest results in a concise way.

The most important message from NASA scientists – echoed by scientists throughout the world – is that the meteor that exploded over Russia on February 15 was not related in any way to the much-publicized asteroid 2012 DA14, which passed only 17,200 miles from Earth later that same day. It was one heck of a coincidence that still “has NASA scientists scratching their heads,” according to the video. Still, an analysis of the orbit of the two objects shows they are not related, although both asteroids apparently have orbits that carry them both beyond, and close to, Earth’s orbit. On that note, you might also enjoy the 45-second video below, showing a preliminary orbit for the Chelyabinsk meteoroid as calculated by researchers Jorge Zuluaga and Ignacio Ferrin at the University of Antioquia in Medellin, Colombia. They used information from dashboard and security cameras that captured the huge fireball to calculate an orbit. According to an article at UniverseToday.com: Using the trajectories shown in videos posted on YouTube, the researchers were able to calculate the trajectory of the meteorite as it fell to Earth and use it to reconstruct the orbit in space of the meteoroid before its violent encounter with our planet … through their calculations, Zuluaga and Ferrin determined the rock originated from the Apollo class of asteroids.

The Apollo asteroids can get farther from the sun than Earth, but they also sometimes come within Earth’s orbit. They are considered Earth-crossers, and some can get very close to the Earth, as the February 15 asteroid over Russia clearly demonstrated. There’s been an increasing awareness on the part of astronomers that these asteroids are, potentially, dangerous, and efforts have been underway for some years now to track them. That’s why we hear so much nowadays about asteroids passing near Earth.

source and credit a earthsky