For once an asteroid strikes when we were kinda, sorta expecting one to. According to the Washington Post, the Russian Academy of Sciences “estimated that the meteor weighed around 10 tons and was traveling at 10 to 12 miles per second (roughly 30,000 to 45,000 mph) when it disintegrated.” The same report estimates that more than 1,200 people were injured by the blast in the Russian city of Chelyabinsk, 900 miles east of Moscow. Based on video of the event, on Dynamics of Cats, Steinn Sigurðsson says it “looks like a fairly slow shallow angle impact, detonating with kiloton++ energy below few km altitude.” On SciencePunk, Frank Swain says “Thanks to the prevalence of dashboard cams in Russia, there’s some amazing footage already circulating.” This asteroid was some 20,000 times smaller than the asteroid DA14, which we had seen a long way coming, which coincidentally came flying between us and the moon at about the same time. We’ll see DA14 again every February 15th for a while now; Wikipedia estimates a 1 in 4.7 million chance that it will hit us between 2080 and 2111. On Starts With a Bang, Ethan Siegel says the hardest asteroids to predict “are the ones that come towards us from the direction of the Sun; we literally never see those coming.” Steinn Sigurðsson says the meteor that exploded February 15th near Chelyabinsk “is a size impact we’d expect every few decades, maybe, quite a bit smaller than Tunguska, but larger than anything we know of in the last 20 years.”
On February 15th, Asteroid 2012 DA14 came hurtling between us and our satellites, twelve times nearer than the Moon, so close that it was visible through binoculars from certain parts of the globe. Greg Laden writes, “This asteroid is not going to hit the earth now or during any of the next few decades, but eventually it may well do so.” On Starts With a Bang, Ethan Siegel writes that the Sun’s 11-year Solar Cycle peaks in 2013, meaning we can look forward to a year filled with solar flares. Even when these are spewed towards Earth, our magnetic field protects us from irradiation. But solar storms can wreak havoc with electrical systems, and Ethan says “if an ultra-massive, fast-moving coronal mass ejection ever heads directly towards Earth, you are literally taking your life into your hands if you do not shut down and unplug all of your electronic devices.” As from an asteroid, serious consequences from a solar storm are only a matter of time.
For more on the asteroid that did hit Earth on February 15th, please see the homepage at scienceblogs.com.