Why Fusion Is More Powerful Than Fission | Neil deGrasse Tyson Explains...

And here's a mind-blowing fact: as powerful as the Fat Man (Nagasaki) bomb was (20 kT yield), only about 30% of the plutonium actually fissioned. By the time that first 30% had "gone off" (a few microseconds after criticality), the sphere of plutonium was beginning to disintegrate and lose it's perfectly spherical shape, resulting in the remaining 70% of the plutonium being ejected in the fireball un-fissioned. The Little Boy U-235 weapon that was dropped on Hiroshima was even worse: only 10% of the fuel fissioned before the core geometry became to disrupted to sustain the chain reaction, with the result that, even though the total mass of U-235 in Little Boy was about 3 times the mass of the Fat Man core, Little Boy only yielded about 15 kT. Of course, it still killed 75,000 people instantaneously and flattened more than 2/3 of the city. In the 1960's just to see how big a blast was possible, the Soviet Union built the "Tsar Bomba", a fission-fusion-fission device that yielded 50 megatons (2,500 times the yield of Fat Man). The fireball was visible some 250 miles away from Ground Zero, the blast wave broke windows 150 miles away, and the crew of the aircraft that dropped the device over Novaya Zemlya was given only a 50/50 chance of survival. They were 28 miles away from the detonation, and the TU-95 Bear they were flying was almost knocked out of the sky - it fell 12,000 feet before the pilot regained control. The crew did survive, just barely. The Tsar Bomba was a one=off experiment, but both the US and Soviet governments had weapons of 15 to 25 megatons in the "active" inventory, meaning ready to use if a war should break out. A 25 megaton air blast on top of downtown Los Angeles, would have caused total destruction and 100% casualties in an 8 mile radius from Ground Zero, and killed anyone exposed outdoors in direct line of sight of the blast out to a radius of about 12 miles. True city killers. During the 10 days of the Cuban Missle Crisis in October 1962, there were about 1,000 such weapons in the inventory, 500 in the US arsenal, about the same number with the Soviets. Fortunately, by the end of the 1980's, it's believed that all weapons over 1.5 megaton yield were decommissioned. We hope.

I need to start remembering to like these videos because the level of content StarTalk provides is spectacular

Gotta appreciate how much knowledge Chuck has accumulated over the years.

The atmospheric ignition discussion in the Oppenheimer movie was the scariest part. Even the thought of it is chilling.

What were your thoughts on Oppenheimer?

One thing I thought may have been mentioned is that the fusion bombs use an initial fission explosion to create the necessary temperature/pressure to initiate the fusion part. This is why we are taking so long to utilise fusion for energy generation. The conditions required are very extreme

"Now that's a fire!" I really hope that was a tribute to Eddie Murphy Raw :)

I literally feel myself getting smarter watching StarTalk. Thank you Dr. Tyson and Chuck.

I surely was ignorant about this thanks Lord Chuck

I liked the part where NDT explained that fusion is thermonuclear, but was disappointed that it was never mentioned that a fission bomb provides the "thermo" part of an H bomb.