Couldn't the meteorite have been hot enough so that the smaller ice fragments were melted by the warmer water? Or was the photo taken almost immediately upon impact? --Dan On 2013-02-18, at 11:01 AM, Joerg Arndt wrote:
* Hans Havermann <gladhobo@teksavvy.com> [Feb 18. 2013 19:38]:
From a National Post (newspaper) article today:
"Viktor Grokhovsky, who led the expedition from Urals Federal University, said Monday the meteorites plucked from the ice-covered Chebarkul Lake so far are less than a centimeter and had an iron content of about 10 percent. Locals saw a big meteorite fall into the lake on Friday, leaving a six-meter-wide hole in the ice. Grokhovsky said a meteorite up to 50-60 centimeters could eventually be found in the lake."
When the initial reports of the 6 m hole surfaced, I thought (looking at a picture of the hole in the ice): That must be a 4 m (or more) chunk of rock. But .5 m? An impact in a surface ice layer surely is not like an impact on ground where a wider hole might be expected.
In short: impact above a certain speed is an explosive event.
Half a ton of material at the speed (exceeding that) of a bullet will at the very least create a neat shock wave inside the water, certainly leaving a much greater hole than its diameter.
I note the (apparent) lack of ice fragments swimming inside the hole and speculate that either the ice in question was immediately rendered into less than even small fragments, or fragments (where not "atomized" and) got thrown out. The latter seems more plausible to me.
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