6 ms·

Here's another one, 1490 in China: https://en.wikipedia.org/wiki/1490_Ch%27ing-yang_event https://en.wikipedia.org/wiki/1490_Ch%27ing-yang_event And of course

by nkoren 5y ago

Here's another one, 1490 in China: https://en.wikipedia.org/wiki/1490_Ch%27ing-yang_event https://en.wikipedia.org/wiki/1490_Ch%27ing-yang_event And of course if the 2013 Chelyabinsk bolide had been just a bit larger, then the city would no longer exist. (Larger size = lower airburst, so even a modest increase in megatonnage can result in substantially more energy transferred to the ground). And there are other recent city-killer-size impacts that are well-known but fortunately didn't have cities underneath them, such as https://en.wikipedia.org/wiki/Campo_del_Cielo https://en.wikipedia.org/wiki/Campo_del_Cielo

sva_ 5y ago
> And of course if the 2013 Chelyabinsk bolide had been just a bit larger, then the city would no longer exist. Looked it up, from Wikipedia: > The power of the explosion was about 500 kilotons of TNT (about 1.8 PJ), which is 20–30 times more energy than was released from the atomic bomb detonated in Hiroshima. The city managed to avoid large casualties and destruction due to the high altitude of the explosion. https://en.wikipedia.org/wiki/Chelyabinsk#2013_meteor https://en.wikipedia.org/wiki/Chelyabinsk#2013_meteor
- gatronicus 5y ago
  The speed of detonation also matters, a meteorite detonation is surely slower than a nuclear bomb which releases the energy in milliseconds.
  - pja 5y ago
    This quite strongly depends on the composition of the metorite and the angle at which it enters the atmosphere. The Chelyablinsk meteor entered at a very shallow angle & was a chondrite with little internal strngth, so it disintegrated over a longer distance forming a “line burst” rather than a single point airburst. Had it entered more steeply, then it would have concentrated it’s KE over a much smaller area, causing much more damage. A nuclear bomb may take a few ms, but after a few 100ms, you’ve got a dense, hot plasma in a small volume. Sounds a lot like the result of a metorite airburst! And indeed, people use the same codes that are used to model nuclear explosions to model meteor airbursts.
    - Arech 5y ago
      Moreover to that - as far as I understand the Tall el-Hammam's paper, the only reason why they ruled out nuclear explosion is "because of the age of the site". Other than that (as I understand), it's indistinguishable. Even though an atomic bomb blast is not applicable because of the historic absence of atomic explosions in the area, an atomic blast produces a wide range of melt products that are morphologically indistinguishable from the melted material found at TeH (Fig. 51). These include shocked quartz64; melted and decorated zircon grains (Fig. 51a, b); globules of melted material (Fig. 51c, d); meltglass containing large vesicles lined with Fe-rich crystals likely deposited by vapor deposition (Fig. 51e, f); spherules embedded in a meltglass matrix (Fig. 51g, h). Also, atomic detonations can replicate the physical destruction of buildings, the human lethality, and the incineration of a city, as occurred in World War II. added: though, I forget to mention, that they also found many chemical elements and compositions that are hard to find under normal conditions (atomic bomb tests included as I understood), but abundant in meteorites.
yongjik 5y ago
On a tangential note, I find it wild that we have so little record of such an extraordinary event that happened as recent as 1490 (when China was prospering under a unified empire): sounds like historians were writing "It was reported that stones rained down from the sky, killing ten thousand, in an obscure town in Gansu province. Anyway, back to the court..."

by nkoren 5y ago

sva_ 5y ago

> And of course if the 2013 Chelyabinsk bolide had been just a bit larger, then the city would no longer exist. Looked it up, from Wikipedia: > The power of the explosion was about 500 kilotons of TNT (about 1.8 PJ), which is 20–30 times more energy than was released from the atomic bomb detonated in Hiroshima. The city managed to avoid large casualties and destruction due to the high altitude of the explosion. https://en.wikipedia.org/wiki/Chelyabinsk#2013_meteor https://en.wikipedia.org/wiki/Chelyabinsk#2013_meteor

gatronicus 5y ago
The speed of detonation also matters, a meteorite detonation is surely slower than a nuclear bomb which releases the energy in milliseconds.
- pja 5y ago
  This quite strongly depends on the composition of the metorite and the angle at which it enters the atmosphere. The Chelyablinsk meteor entered at a very shallow angle & was a chondrite with little internal strngth, so it disintegrated over a longer distance forming a “line burst” rather than a single point airburst. Had it entered more steeply, then it would have concentrated it’s KE over a much smaller area, causing much more damage. A nuclear bomb may take a few ms, but after a few 100ms, you’ve got a dense, hot plasma in a small volume. Sounds a lot like the result of a metorite airburst! And indeed, people use the same codes that are used to model nuclear explosions to model meteor airbursts.
  - Arech 5y ago
    Moreover to that - as far as I understand the Tall el-Hammam's paper, the only reason why they ruled out nuclear explosion is "because of the age of the site". Other than that (as I understand), it's indistinguishable. Even though an atomic bomb blast is not applicable because of the historic absence of atomic explosions in the area, an atomic blast produces a wide range of melt products that are morphologically indistinguishable from the melted material found at TeH (Fig. 51). These include shocked quartz64; melted and decorated zircon grains (Fig. 51a, b); globules of melted material (Fig. 51c, d); meltglass containing large vesicles lined with Fe-rich crystals likely deposited by vapor deposition (Fig. 51e, f); spherules embedded in a meltglass matrix (Fig. 51g, h). Also, atomic detonations can replicate the physical destruction of buildings, the human lethality, and the incineration of a city, as occurred in World War II. added: though, I forget to mention, that they also found many chemical elements and compositions that are hard to find under normal conditions (atomic bomb tests included as I understood), but abundant in meteorites.

yongjik 5y ago

On a tangential note, I find it wild that we have so little record of such an extraordinary event that happened as recent as 1490 (when China was prospering under a unified empire): sounds like historians were writing "It was reported that stones rained down from the sky, killing ten thousand, in an obscure town in Gansu province. Anyway, back to the court..."