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This video [1] from The Guardian include the same video in that tweet, but also has a few other angles which gives a better appreciation of how big that thing was. [1] https://www.youtube.com/watch?v=93tV6-0Ugwk
Al Jazeera is reporting that according to the president in Lebanon, it was almost three thousand tons of ammonium nitrate that blew up https://www.aljazeera.com/news/2020/08/huge-explosion-rocks-... .
I am seeing other analyses that put the size of the explosion at about one tenth of this size. The analysis in this Twitter thread correlates the observed degree of damage with the distance from the explosion. It comes up with an estimated 240 tons TNT-equivalent, though naturally this comes with a considerable margin of error. https://twitter.com/GeorgeWHerbert/status/129071971954515968... This Twitter thread is mak…
My fluid mechanics prof told the class that a scientist in the 1940's published the yield of the Hiroshima bomb. Since this was top secret, he got investigated. But he showed how the yield could be calculated from the film of the explosion - how fast the blast radius expanded. So I imagine the yield of the Beirut explosion could be calculated the same way from the video.
http://sites.science.oregonstate.edu/~restrepo/MTH481/Classn...
From videos:
R=450m
t=1.5s
rho=1.2kg/m3
E=9.84E12 kg.m2/s2 or 9.84E19 erg
Equiv TNT = 2.5kTonnes -TNT
Equiv AN = 5400 Tonnes
So double what current media is saying.
edit:formatting.
Earlier quoted context omitted.
From what I understand, ammonium nitrate isn't particularly flammable, until it gets hot--then it gets explosive. Furthermore, ammonium nitrate conflagrations tend to give a distinctive reddish smoke cloud. The cloud accompanying the big explosion has a very distinct red tint to it, indicating that it's a result of the ammonium nitrate going off. That before it doesn't, which suggests that the ammonium nitrate wasn't…
Ammonium nitrate does not release nitrogen dioxide unless it undergoes high-order detonation.
The deflagration of solid AN may produce NOx (an orange plume)...
Thermal decomposition produces nitrous oxide (laughing gas) and water.
[1]https://www.sciencedirect.com/science/article/pii/S001021801...
https://twitter.com/quantian1/status/1290695231910875136
CHEMISTRY FACT: Explosives have characteristic "detonation velocities" at which shockwaves expand. Smartphone video records at 30 FPS, so the adjacent frames here suggest the front expands at ~100 m/(1/30 sec), or 3,000 m/sec. Consistent with ammonium nitrate, not black powder.
This was confirmed a few hours later:
https://twitter.com/BBCBreaking/status/1290758551737192455
Lebanese president blames 2,750 tonnes of ammonium nitrate left in warehouse unchecked for six years for devastating Beirut blast
EDIT: By the way, one of my friends was almost killed by the explosion. Thankfully they're ok. But they said:
https://twitter.com/cyrilzakka/status/1290766217989500928
This was terrifying to experience. Hospitals are being overrun with injured people. We need blood donations and disaster relief. Help however you can.
As a US citizen, is there any way I can help directly? Is there any organization that ships blood donations directly to a disaster site? I suppose that would be very difficult, so the answer is probably no; it's frustrating not being able to assist.
Earlier quoted context omitted.
If you think this shouldn't be the clear headline, then I guess we consider news to be different things. I'll go back to reading next in my feed how George R R Martin is racist because he mispronounced someones name (Not an article in the Guardian, and the Guardian's coverage is exceptional for Beirut compared to others like CNN or Fox) [edit] Does the media not care about the largest peacetime explosion in a capital…
The news is way worse than that. A couple notable things they mostly buried just this past week: The George Floyd bodycam video leaked out, destroying the BLM narrative (see https://news.ycombinator.com/item?id=24046940 for DailyMail). ABC doesn't cover it. CBS and NBC edit out "Stop resisting". Youtube suppresses it from trending. NBC even had privately seen the bodycam video a month prior, leaving them no excuse fo…
Thus, the BLM narrative that police violence is excessive is still compelling if you subscribe to the belief that someone placing their knee and weight on a detained person's neck for 8 minutes is excessive, regardless of other circumstances.
Ask yourself if you think the situation could have been resolved differently, without loss of life. If outcome isn't important to you because of a toxicology report, mannerisms, circumstances of arrest, other reason to deny life... then a certain unorganized group of people would like to remind you and many others like you that _black lives matter_.
But alas, to say the leaked body cam footage "destroys the BLM narrative" implies you won't care about reporting at all if you resort to regurgitating clickbait-language.
Al Jazeera is reporting that according to the president in Lebanon, it was almost three thousand tons of ammonium nitrate that blew up https://www.aljazeera.com/news/2020/08/huge-explosion-rocks-... .
The US Chemical Safety Board has a video[1] discussing ammonium nitrate, in relation to an explosion in West Texas on April 17th, 2013. That incident involved 40–60 tonnes of ammonium nitrate, killed 15 people and leveled a neighbourhood. [1]: https://youtu.be/pdDuHxwD5R4
Earlier quoted context omitted.
My fluid mechanics prof told the class that a scientist in the 1940's published the yield of the Hiroshima bomb. Since this was top secret, he got investigated. But he showed how the yield could be calculated from the film of the explosion - how fast the blast radius expanded. So I imagine the yield of the Beirut explosion could be calculated the same way from the video.
Paper in question. http://sites.science.oregonstate.edu/~restrepo/MTH481/Classn... From videos: R=450m t=1.5s rho=1.2kg/m3 E=9.84E12 kg.m2/s2 or 9.84E19 erg Equiv TNT = 2.5kTonnes -TNT Equiv AN = 5400 Tonnes So double what current media is saying. edit:formatting.
Earlier quoted context omitted.
There's a story about Feynman estimating yield by dropping pieces of paper and seeing how far they'd travel in the shockwave
Feynman told that story about Fermi.
Fermi also put Dyson down gently once "A successful theory must have either a strong physical intuition or a rigorous mathematical basis: you have neither"