00:00The most powerful weapon humans have ever detonated was deliberately cut in half before
00:04it was ever dropped.
00:05And even at half strength, its record still stands today.
00:08So here is the strange question.
00:10If you already built the biggest bomb in history, why would you shrink it on purpose?
00:14The answer is hiding in one flight, in October 1961.
00:18On October 30th, a modified 2-95 bomber climbed toward the Arctic, carrying a device the world
00:24would soon call the Tsar Bomba.
00:25The moment it left the plane, a huge parachute opened in the sky.
00:29That parachute was not a detail.
00:31It was the difference between life and death.
00:34The bomb had to fall slowly, so the crew could get away.
00:37And you can see the whole problem in one image.
00:39The bomb is descending.
00:41The plane that delivered it is racing the other direction.
00:44Humanity built the explosion, then had to figure out how to escape it.
00:48But the parachute only solved the problem in the sky.
00:51On the ground, scientists were wrestling with something far more permanent.
00:54To understand why they compromised, rewind three years.
00:58In 1958, the United States, the Soviet Union, and Britain began talks about banning nuclear tests.
01:04One by one, they paused their own testing.
01:07But every negotiation ran into one wall, how do you prove the other side is not cheating?
01:11Being able to detect a test, and being willing to let inspectors see everything, were two very different things.
01:17Then a single flight shattered what little trust was left.
01:20On May 1, 1960, an American U-2 spy plane was shot down over Soviet territory.
01:26The Paris summit collapsed.
01:28Every question that might have been settled at the table was pushed back into confrontation.
01:32By 1961, the world was tense again, and Soviet leaders wanted one unmistakable demonstration of power.
01:38The super bomb project accelerated.
01:41Its target yield was 100 megatons.
01:43That number describes energy, not weight.
01:46100 megatons meant the force of 100 million tons of TNT.
01:50When a test is really a message, the explosion itself becomes political language.
01:54The bigger the number, the louder the threat.
01:56But the same number meant something else to the scientists building it.
02:00One of them, Andrei Sakharov, had warned about the arms race for years.
02:04He knew what others preferred not to think about.
02:07The flash, the fireball, the shockwave, those are the parts you can see.
02:11The parts you cannot see can outlast them all.
02:14Radioactive material rides the wind.
02:17It falls on soil, in water, into lungs.
02:20A test site cannot order the wind where to blow.
02:23So the real question was never just whether the bomber could come home.
02:25It was where the invisible debris would land.
02:28And that is when the plan changed.
02:31The yield was cut from 100 megatons down to 50.
02:34Reducing radioactive fallout was a central reason.
02:37So there is the answer.
02:39Cutting the bomb in half was a way of limiting the consequences.
02:42But half of an impossible number is still impossible.
02:4550 megatons had never existed before.
02:48Now, back to the bomber.
02:49The bomb was released from about 10 and a half kilometers up, drifting down under its parachute
02:54while the plane fled.
02:55It detonated roughly 4 kilometers above the ground.
02:58A flash of light tore open the sky over Novaya Zemlya.
03:02Crew members later recalled it was still visible a thousand kilometers away.
03:06The mushroom cloud climbed to about 64 kilometers.
03:09The shockwave circled the entire planet, three times.
03:12One bomb.
03:13One test site.
03:15And its effects reached the whole earth.
03:17That is the image the Tsar Bomba left behind.
03:20A mushroom cloud racing into the stratosphere, and a record humans set with their own hands.
03:25But if a test that powerful could be built, did the world become safer?
03:28What happened next answered that almost immediately.
03:31Less than a year later, the Cuban Missile Crisis brought the superpowers to the brink again.
03:36Having enormously powerful weapons did not remove fear.
03:39It did not make either side trust the other.
03:41A successful explosion proves how strong a weapon is.
03:44It cannot promise how the next crisis will end.
03:47In 1963, the United States, the Soviet Union, and Britain finally signed the Partial Test Ban Treaty,
03:53banning nuclear tests in the atmosphere, in space, and underwater.
03:57Talks that began in 1958 had to survive collapse and new crises to reach that single page.
04:02And even then, underground testing remained legal.
04:06Sakharov's own path drifted further from the world of ever larger numbers.
04:09He kept calling for limits on nuclear weapons.
04:12He pushed for disarmament.
04:13He campaigned for human rights.
04:16In 1975, he was awarded the Nobel Peace Prize,
04:19and Soviet authorities refused to let him travel to Oslo to accept it.
04:23His wife went in his place.
04:25A scientist who once helped build a giant bomb would later be honored for defending human rights.
04:29The same life, two completely different chapters.
04:32When we look back at that test, the detail worth remembering might not be the size of the explosion.
04:37It is the two decisions made right before detonation.
04:40Cut the yield.
04:41Then let the parachute by the crew some distance.
04:44To create a demonstration that big, humans first had to negotiate a little room for themselves.
04:49But a plane can buy time with a parachute.
04:52Stopping a nuclear arms race takes far longer than building the bomb.
04:55That day, the bomber finally flew away from the islands.
04:59And everyone who made those decisions still lives on the same planet we do.
05:02To be on the same boat as the sun is before.
05:06So, this is what it might seem like.
05:32You
