Tag: meteorite

A skydiver’s helmet cam captures a meteorite zipping past him as it falls.

2:11 pm

A skydiver’s helmet cam videotapes a meteorite zipping past him as it falls.

The incident happened back in the summer of 2012, when skydiver Anders Helstrup and other members of the Oslo Parachute Club took to the skies above Hedmark, Norway. Helstrup documented the jump with two cameras fixed to the front and back of his helmet. Helstrup tells NRK (the largest media outlet in Norway) that on the way down he felt β€œsomething” happen, but didn’t know what. It was only after landing and reviewing his camera footage that he discovered something shocking: a rock had fallen from the heavens and missed him by just a few yards.

Video below the fold. The news woman is annoying, but the footage is quite cool.
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The accumulated evidence from the Chelyabinsk meteorite now suggests the risk of large asteroid impacts might be ten times greater than previously estimated.

12:07 pm

The accumulated evidence from the Chelyabinsk meteorite now suggests the risk of large asteroid impacts might be ten times greater than previously estimated.

The Chelyabinsk asteroid had approached Earth from a region of the sky that is inaccessible to ground-based telescopes. In the 6 weeks before the impact, it would have been visible above the horizon only during the daytime, when the sky is too bright to see objects of its size, says Borovička.

β€œThe residual impact risk β€” from asteroids with yet-unknown orbits β€” is shifting to small-sized objects,” says Peter Brown, a planetary scientist at the University of Western Ontario in London, Canada, and an author on the Nature papers.

Of the millions of estimated near-Earth asteroids 10–20 metres in diameter, only about 500 have been catalogued. Models suggest that an object the size of the Chelyabinsk asteroid hits Earth once every 150 years on average, Brown says. But the number of observed impacts exceeding 1 kiloton of TNT over the past 20 years alone hints at an actual impact risk that may be an order of magnitude larger than previously assumed,

The data also now suggests that the Chelyabinsk asteroid was twice as big as previously thought, and that it had an almost identical orbit to a much larger already known asteroid.

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Largest in a century.

9:58 am

More on today’s Russian meteorite: Largest in a century.

My earlier skepticism appears incorrect. This impact actually happened.

Note the article’s sense of outrage and panic that we aren’t looking for these types of rocks:

Although a network of telescopes watches for asteroids that might strike Earth, it is geared towards spotting larger objects β€” between 100 metres and a kilometre in size. “Objects like that are nearly impossible to see until a day or two before impact,” says Timothy Spahr, Director of the Minor Planet Center in Cambridge, Massachusetts, which tracks asteroids and small bodies. So far as he knows, he says, his centre also failed to spot the approaching rock.

Yet, today’s impact actually illustrates the wisdom of excluding this kind of small asteroid from searches. They aren’t big enough to do serious harm, and trying to find them would hamper searches for larger asteroids that do pose a serious risk.

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