TNT equivalent is a convention for expressing energy released in explosions. One ton of TNT equals 4.184 gigajoules (1 gigacalorie). Kiloton equals 4.184 terajoules, megaton equals 4.184 petajoules
Founded in 1971 by environmental activists in Canada. Comprises 26 regional offices in 55 countries. Operates under Greenpeace International based in Amsterdam. Receives funding from 3 million individual supporters and foundations
Nuclear fission was discovered in 1938 by Meitner and Frisch. Leo Szilard patented neutron-inducted chain reaction in 1934. Einstein warned Roosevelt about Nazi nuclear threat in 1939
Uranium-235 is a fissile isotope making up 0.72% of natural uranium. Discovered in 1935 by Arthur Jeffrey Dempster. Has a half-life of 703.8 million years. Fission cross section is about 584.3 barns for slow neutrons
Explosion occurs when matter expands rapidly with extreme energy release. Volcanic eruptions happen when magma rises with dissolved gas. Supernovae and stellar flares are major astronomical explosions. Meteor impacts create explosions at speeds up to 11.2 km/s
Nuclear explosions result from high-speed nuclear reactions, either fission or fusion. First manmade nuclear explosion occurred at Trinity test site in 1945. US dropped Little Boy on Hiroshima in 1945, killing 70,000 people. USSR tested first nuclear weapon, RDS-1, in 1949. First thermonuclear weapon, Ivy Mike, detonated in 1952