Physicist Estimates the Energy of the Beirut Explosion

Luis Batalha shared a series of tweets with his calculations using the displacement of a wedding dress.
Loukia Papadopoulos

The recent Beirut explosion shook the world and devastated entire communities. Among the news coverage, a video surfaced from ABC News of a bride having her wedding photoshoot disrupted by the explosion.


Now, a physicist named Luis Batalha has released a series of tweets stating he can calculate the energy of the Beirut Explosion using the displacement of the wedding dress. The posts have garnered him a lot of attention.

Here is how Batalha estimated the energy of the explosion in his own words:

"The energy released by an expanding gas across one direction is: E=Fd=PAd=PΔV To calculate the volume displaced (ΔV) we use the displacement of the wedding dress ~2m. This means that the volume of the spherical shell of displaced air was: ΔV= 4πd²r =4π(1400m)²(2m)

Knowing that the pressure of the compression wave in the air is approx. 10³N/m², we calculate the energy of the shock wave E_wave=PΔV. Taking into account the efficiency of the explosion we calculate that the energy of the explosion was approximately ~100 tons of TNT.

This method was used by Enrico Fermi to determine the energy of the first atomic bomb explosion (Trinity 1945 - 20 kilotons of TNT). He threw a few pieces of paper in the air and measured the displacement."

One of Batalha's followers was quick to point out that the distance of the bride from ground zero was unknown to which the physicist replied that he identified where she was thanks to a sign on the store behind her. "That's how I calculated that she was 1400 m from ground zero," added Batalha.