The Beirut Explosion

For several reasons, it was not likely an atomic bomb…

But it was a BIG bomb…

The explosion did trigger a powerful blast wave that apparently shattered windows across Beirut, and it was briefly visible as an expanding, shell-like cloud — something often seen in historical footage of nuclear detonations. But Pfeiffer noted such blast-wave clouds, known to weapons researchers as Wilson clouds, are made when humid air gets compressed and causes the water in it to condense. In other words: They aren’t unique to nuclear bombs.

A back-of-the-envelope calculation reshared on Twitter by Narang estimates the blast was equivalent to about 240 tons of TNT, or about 10 times what the US military’s “mother of all bombs” is capable of unleashing. By contrast, the Little Boy atomic bomb that the US dropped on the Japanese city of Hiroshima in 1945 was about 1,000 times as powerful.

The Davy Crockett was one-tenth as strong as the estimated strength of the Beirut explosion but still had a distinctive flash that’s missing from Tuesday’s blast. No reports suggest there was radioactive fallout after the Beirut blast, which would have been quickly detected.

I’m curious the thoughts of the @physicists

There were reports of a large amount of ammonium nitrate in storage there, often used as fertilizer or for demolitions. Storing explosives in a busy populated area is just a bad idea. If this is terrorism, the terrorists didn’t have to work very hard to cause this.


It was adjacent to silos, now destroyed, that stored 85% of the country’s grain.

Just a single person in Beirut with a Geiger counter can tell:

  1. If the explosion is caused by a nuclear device
  2. The approximate yield

I don’t think it’s wise to make politically charged statements on the source of the explosion without this piece of evidence.

Edit: In fact, I heard on the news that no radiation fallout has been detected, which is evidence against a nuclear device source stronger than any approximate yield calculation from a video.


Israeli scientists probably have the equipment needed to test for airborne fallout, and if not Israeli scientists then other scientists across the continent. I’m sure if it were a nuclear explosion we would have already heard about it.

That stinks. It’s a good time for western countries to show a moral backbone and help the people of Lebanon.


We should help them, but the situation in the developing world due to COVID is grave. Much food assistance will be needed all over the world.

There were several lines of evidence that came in that showed it is very likely a nuclear bomb. Saying it is not a nuclear bomb is far less charged than saying it is.

I’m not saying that it is not a nuclear explosion, however I believe that saying anything about the source of the explosion is politically charged. My point is that saying something like this must be done carefully after all lines of evidence have been carefully weighted.


Very true. All I am saying is politics shouldn’t get in the way of helping the Lebanese people.

I haven’t run across that evidence. If the only evidence is the size of the blast then it is pretty poor evidence. Experts were able to rule out a nuclear explosion almost immediately, just by looking at the blast itself (i.e. lack of a bright flash and thermal pulse).

Yes, these are examples of relevant lines of evidence.

I don’t see anything about this explosion that makes me think of a nuclear weapon(no blindingly bright flash of light, for example).

Rather it appears from all the multiple videos that have surfaced of the explosion that there was a protracted ongoing fire with many, much smaller explosions, leading up to that final giant blast.

Seems more likely to me this is a case of a fire having started in a facility for storage of large amounts of chemicals (this was an area for storage of many types of goods), some of which caught fire and started exploding well before other more stable ones. Once the fire got hot enough, or other exploding chemicals exploded closer, the “final” one went off.

This appears to me to have many of the same features as the 2015 Tianjin explosion in China. A protracted period of smaller explosions leading up to some final cataclysmic blast.

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Numerous reports show that the main explosion came from a warehouse that, for the last 6 years, held approximately 2,700 tons of ammonium nitrate (AN). AN is used both as a fertilizer and an industrial explosive. The 1995 Oklahoma bombing used about 4,800 pounds of ANFO (AN + fuel oil) and other explosives.

A nuclear yield of the Beirut blast would generate:

    • An electromagnet pulse (EMP) that would scramble most of the electronics within miles - none observed
    • A gamma-ray flash that would have been detected by networks of satellites operated by several concerned nations - not reported
    • A radioactive fall out plume that by now would be lighting up every radiation detector in the Middle East - no news yet

The really scary thing is that the AN was kept in an poorly-secured warehouse for 6 years, with enough explosive material to build thousands of terrorist IEDs.


Except that mushroom cloud… :slight_smile:

I wonder if this tragedy should push regulatory bodies around the world to double check if there are stashes of ammonium nitrate being stored in a similarly insecure manner in their country. I wouldn’t be surprised if on paper there must have been some regulations, but they were not properly enforced.

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Apparently the warehouse with all the AN was right next door to one storing fireworks. Apparently that caught fire first and in the videos just before the huge explosion you can see and hear fireworks going off. Sorry tinfoil hat crowd but this wasn’t an atomic explosion. Just a damn big conventional one.

I wonder how it compares to the huge ammo ship explosion in Halifax, Nova Scotia back in 1917?

Halifax Explosion

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The whole thing is just … ghastly. As a chemist in the Midwest I just can’t even begin to comprehend how they didn’t connect that grain silos and 2,700 tons of ammonium nitrate were anything but a ticking time bomb.

Having grown up in, shall we say, less regulated parts of the country, I’ve had my share of fun with explosions. I’ve felt a (small) shock wave from an explosive and it’s scary, I just can’t imagine the one you see in these videos.


Mushroom clouds are not unique to nuclear explosions.


Of course they aren’t, but that is what had people wondering.

Don’t worry, I’m sure the conspiracy theorists are already having a field day with this.

An attack by Martians ordered by George Soros … :wink:


The back story behind the ammonium nitrate is just as incredible. Turns out it was on a Russian freighter whose owner declared bankruptcy while the ship was in port in 2014 and left the crew and cargo in limbo. The captain and some of the crew were detained and ordered to dispose of the dangerous cargo themselves, sell it to someone. When this couldn’t be done the Beirut port officials had all 2750 tons off-loaded and stored improperly in an unsafe warehouse lacking any fire prevention or environmental controls. Apparently several groups in the city knew of the immense danger and tried multiple times in the preceding 6 years to get the authorities to take steps to prevent a disaster. Too late now.