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Wanggongchang Explosion (wikipedia.org)
204 points by benbreen 19 days ago | hide | past | web | favorite | 41 comments



While the Wikipedia article says "no academic consensus has been reached" it seems pretty clear from the "possible causes" section that a bolide (meteor exploding in the air above) is the only explanation listed which seems to fit the facts.

I'm curious, therefore, why the lack of consensus? Is there any evidence inconsistent with the bolide hypothesis? Or is there just no positive proof whatsoever (e.g. some type of meteor residue or other) so it can never be conclusively demonstrated?


Except any sound before the initial explosion would be impossible. The meteor would be traveling faster than the speed of sound, the first thing felt or heard by anyone would be the light and heat of the explosion followed by the shockwave.

When anything combustible is aerosolized and mixed with oxygen, it allows it to explode. This is how thermobaric explosives work https://en.wikipedia.org/wiki/Thermobaric_weapon see also https://en.wikipedia.org/wiki/Dust_explosion

Gunpowder doesn't need oxygen, but it burns instead of exploding. If there was an initial set of fires and smaller explosions that dispersed unburned gunpowder and wood/grain dust into the sky, once it was dispersed a flash could have spread through the dust cloud and created a huge explosion as described. This theory would explain both the initial disturbances and the huge explosion at the end, but I don't see it mentioned anywhere.


If the meteor passed overhead and then exploded some distance away you'd get the sound before the shockwave.

Perhaps the passby tore the roof off the armory and sucked black powder into the air, and then the impact shockwave caused a fuel/air-like explosion?

Also note that the description is by survivors, so the sequence of sounds maybe different away from the impact.


> If there was an initial set of fires and smaller explosions that dispersed unburned gunpowder and wood/grain dust into the sky, once it was dispersed a flash could have spread through the dust cloud and created a huge explosion as described.

That was my thought too, especially with the description of the initial rumbling noises. Gunpowder burning in a small space might well provide the energy needed to disperse something flammable in a cloud above the armory which could then be ignited at some interval after it was created, providing a fuel-air explosion above ground level which would explain the over pressure damage without burning, the shape of the mushroom cloud, and the magnitude of the explosion.


> The ground around the immediate vicinity of Wanggongchang Armory, the epicenter of the explosion, had sunken for over 2 zhangs (about 6.5 m or 21 feet), but there was a notable lack of fire damage

it seems a bit improbable that a bolide would just so happen to hit the armory. Given that bolide events are rare to begin with, the low chance of hitting a military building is enough to make me skeptical.

I have no idea what contemporary chemical explosives were extant, but if there were any plausible agent I would favor that instead.


> I have no idea what contemporary chemical explosives were extant

Only black-powder. Nitroglycerin, the first practical explosive more powerful than black-powder, was invented two centuries later.


> it seems a bit improbable that a bolide would just so happen to hit the armory. Given that bolide events are rare to begin with, the low chance of hitting a military building is enough to make me skeptical.

Well, isn't the probability of hitting the armory identical to that of hitting anywhere else on the planet?


Yes, and there's a very big number of things in the "anything else" category, and only very few things in the "armory" category.

On the other hand explosive materials accidents happen where big amounts of explosive materials are stored, and there's few places in the "anything else than armory" category so the event is more likely.


Yes, but the probability of hitting a place that contains many other explosive agents which could cause the same effect is far far lower than hitting anywhere else on the planet.


An airborne explosion of the bolide (which is the most popular hypothesis) could easily cause a secondary explosion in armory.


If it were not for the astounding coincidence of it being a munitions factory, it looks to me like we would be assuming an impact. But, given the absence of any smoking gun (e.g. impact crater), and the abundance of gunpowder on the site, I'm not surprised that there is debate.


The following resources provide some context about the frequency of high energy atmospheric meteorite impacts:

https://cneos.jpl.nasa.gov/fireballs/

https://en.wikipedia.org/wiki/List_of_meteor_air_bursts

Edited 14:32 MET


A combination of meteorite air burst with compounding effects from a combustion explosion due to ammunition storage seems like it could have unpredictable effects that could account for some of the strange outcomes seen here.


Indeed - a bolide crossing the city from northeast to southwest is by far the most plausible explanation, though, as the sky was clear, it would surely have been seen as a fireball, as in Chelyabinsk? Therefore, I would guess that the "bright streak" was coincident with the initial "roaring rumble", rather than following it, and the reports are conflating the passage of the fireball with its final explosion.

If it caused the detonation or deflagration of the armory's gunpowder, that might account for most of the clouds, including trails of smoke from burning fragments thrown high into the air (the "messy strands of silk"?)




Wonder how it compared to the Tianjin explosion in 2015:

https://www.youtube.com/watch?v=4nr6Tlu0EvM

Wait for the 3rd explosion at 0:50.


Wanggongchang is estimated to have been about 10 kilotons, roughly the equivalent of the Hiroshima nuke. Tunguska was at least 10 megatons. In comparison, the three explosions at Tianjin add up to a measly 360 tons of TNT [1].

[1] https://en.wikipedia.org/wiki/2015_Tianjin_explosions


The largest PEPCON explosion was about 1 kiloton: (1m37s) https://www.youtube.com/watch?v=gGSx54CkWsQ

https://en.wikipedia.org/wiki/PEPCON_disaster


Or another fireworks disaster, in Netherlends 2000, a series of explosions from 0.8kT to 5kT.

https://en.wikipedia.org/wiki/Enschede_fireworks_disaster


I think you are 3 orders of magnitude out. The biggest blast at Enschede was 5000 kg of tnt, Vs 5000000kg which would be 5kT.


Oops, you're right.

Still damn impressive on the videos though.


Maybe they had learned to make picric acid. One of the early methods involved nitrating silk. But for that, you need nitric and sulfuric acids.

Nitric acid you can make from sulfuric acid and alkali nitrates. And sulfuric acid was discovered by Rhazes (Zakariya al-Razi) in ~900 AD. So it's possible.

Or maybe ammonium nitrate. That was known in antiquity, but not as an explosive. But maybe they discovered that. And indeed, mixtures of ammonium nitrate, picric acid and anything carbonaceous are decent ~high explosives.


The energy released would have required at least 20,000,000 pounds of high explosive. There is simply no way they had the resources to manufacture in those quantities.


True enough, but maybe the reports have been exaggerated.

The Texas City disaster,[0] involved ~2 million kg of ammonium nitrate. But TFA notes that the facility produced only ~400 kg gunpowder per day. Let alone ammonium nitrate, if any.

So what, bolide?

0) https://en.wikipedia.org/wiki/Texas_City_disaster


Wikipedia puts the TNT equivalency of ammonium nitrate at 2.38 kg of ammonium nitrate for one kg of TNT. The Texas City explosion had 2,200 tons of ammonium nitrate present, so my estimate for the potential TNT equivalency of that explosion is just less than one kiloton. Meaning the Wanggongchang explosion was 10-20x as big (my math might be a bit off there, but probably not by an order of magnitude.)

Even the Halifax explosion wasn't nearly as big as the Wanggongchang explosion. It's hard for me to fathom they had so much explosives there.


Bolide is certainly the most likely explanation, in my opinion.


It’s interesting to see the use of a number of non-standard units of measurement in describing the event.


> Tianqi Emperor's only remaining heir, the 7-month-old Crown Prince Zhu Cijiong (朱慈炅), died from the shock.[1]

How does one die of shock? I'm curious if this is just an old medical description or possibly the weakness of a 7-month old baby at the time.


Explosions can cause shock waves which can cause injury in and of themselves (as opposed to injuries cause by thrown objects or fire). This could be what they're alluding to. I couldn't access the document[0] referenced in the Wikipedia article to confirm this reading.

[0]: https://www.allbestessays.com/essay/Solving-a-Mystery-of-400...

Mythbusters often highlighted this when working with explosions by using rupture disks at different distances from the explosion to measure the amount of damage incurred due to the pressure wave.

https://www.flowcontrolnetwork.com/news-reports/article/1555...


Medical shock refers to very low blood pressure which results in poor oxygenation. It's usually fatal if left untreated. (It can be treated with oxygen and IV fluids). I would guess, though, that 'shock' is used in this context to refer to the explosion (as in shock wave).


If “the shock” were meant to be interpreted as medical shock, I would expect the definite article to be omitted. Compare:

He died of shock. (medical condition)

He died of the shock. (single, definitive event, e.g., fright or shock wave)

Might be reading too much into it, but lends credence to the shock wave interpretation. Anyone have access to the original text? Might clear it up.


The original source is available on Wikisource: https://zh.wikisource.org/wiki/%E9%85%8C%E4%B8%AD%E5%BF%97#%...

皇貴妃任娘娘所居之室器物隕落,任娘娘於天啟五年十月初一日所生皇第三子,於是日受驚後遂薨逝

Translates roughly (with the caveat that my Literary Chinese sucks) as:

In the imperial consort Lady Ren's living quarters, things fell down and the emperor's third son she had given birth to on the first day of the tenth month of 1625, having been shocked on that day, subsequently passed away.

The paragraph I took that quote from begins with the description of a dragon sighting four years earlier, which might give you an idea of how reliable that source is.


Thank you for this. Didn't expect my question to get answered so thoroughly but at the same time it doesn't answer whether it was the blast shock or generic medical shock, I'm guessing blast shock given how everything in the house was rattled.


Medical shock is much more vague. The version mentioned is one form which may itself have several different causes. Don't try to impress a medical doctor by mentioning shock.

But the cause of death of the heir is far more profoundly vague, linguistically, although at the same time more specific.


Acute stress causes about 30% of cardiac deaths.

https://www.ncbi.nlm.nih.gov/pubmed/18827773


Or someone murder him, taking the opportunity given by the chaos of circumstances. You never know.


Bolide. The area, scale and dispersion of effects in the descriptions is incongruent with a point source explosion of black powder.


Imagine being killed in such an explosion, never really knowing what was happening as you died.


I’m not one of the down-voters, but the death was likely near instant for most involved.


I know this is a quite off topic but as I was reading this and got to the "silk strands" clouds, I couldn't stop thinking about Death Stranding and the "voidout" events in the game.




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