Convert megatonne TNT to exajoule

The joule is tiny, so the everyday unit is the megajoule: 1 kWh is 3.6 MJ, a litre of petrol holds about 33 MJ and a litre of diesel 36, and Australian and New Zealand food labels count in kilojoules towards a daily 8,700 kJ (8.7 MJ). Gas bills in Canada are in gigajoules, 1 GJ being 278 kWh or roughly 26 m³ of gas, and a full 50-litre tank of petrol is 1.7 GJ. National statistics use petajoules and exajoules: the UK consumes around 7 EJ of primary energy a year, the world some 620 EJ.

The tonne of TNT is defined as 4.184 GJ, about the energy released by detonating a tonne of the explosive, and is the unit of nuclear yields and of large explosions and impacts. The Hiroshima bomb was about 15 kt, the largest weapon ever tested (Tsar Bomba, 1961) 50 Mt, the 2020 Beirut explosion roughly 0.5 kt, and the Chicxulub impact that ended the dinosaurs on the order of 100 million Mt.