The Most Insane Weapon You Never Heard About

Between 1945 and 1950, technological change accelerated dramatically: in 1905 only 3% of US homes had electricity and monarchs ruled much of the world, but by 1950 the world had jet planes, TVs, microwaves, and nuclear bombs, creating psychological disorientation for people who witnessed this compression of change.

“If you were 40 in 1945 that means you were you had been born in 1905 – back then monarchs ruled over much of the world, only 3% of homes in the US had electricity, cities were dominated by horses, the first experimental planes had just flown... By 1945, 24 million soldiers and 50 million civilians had died in two world wars. And suddenly there were TVs, microwaves, jet planes and … nuclear bombs. They kind of broke the brains of the people alive back then.”

The nuclear arms race was fundamentally irrational: each superpower would develop a more powerful bomb and detonate it to demonstrate superiority, prompting the other side to build something more destructive in response, creating an endless cycle of escalation driven by fear rather than strategic necessity.

“In a way the nuclear arms race was pretty daft. One superpower would develop a powerful new bomb and detonate it. And then the other side would build something more powerful and blow it up, and this would continue endlessly. A dirty and wasteful game of creating more and more horror that seemed totally reasonable at the time.”

Sundial would not be a warhead transported by bomber or missile but a stationary bomb that could remain in a backyard, the center of a country, a remote island, or on a ship—the rationale being that if a bomb can destroy the world, deployment becomes irrelevant, demonstrating Teller's full comprehension of the weapon's apocalyptic nature.

“Sundial wouldn't be some warhead loaded up onto a bomber and dropped on a target. No. It would be a backyard bomb. After all, if a bomb can destroy the world, why bother moving it at all? No need to bring it close to your enemies, you could as well just put it in your backyard. Maybe it would have actually been put in the center of the country, maybe it would have been put on a remote island or stored on a ship, we don't know what the actual plans were. But this underlines how insane this weapon was and that Teller knew exactly what he was proposing.”

Teller incessantly lobbied scared politicians to green light more devastating nuclear weapons, and his timing was opportune because politicians were terrified by Soviet nuclear progress, giving him a blank check from the military to realize his destructive vision within just a few years.

“He didn't care one bit and incessantly lobbied scared politicians to green light more devastating nuclear weapons. And lucky for him, his timing was just right. Terrified by the rapid nuclear progress of the Soviet Union, he got a blank cheque from the military to bring his most destructive fantasy to life. It took him only a few years to make them a reality: The Hydrogen bomb.”

Although Sundial was never built, at the peak of the cold war humanity accumulated over 70,000 nuclear weapons, meaning that instead of a single world-destroying bomb, superpowers built tens of thousands of nuclear weapons of all types and sizes distributed across submarines, bunkers, and silos.

“The elephant in the room is that while Sundial is clearly insane – humanity still kind of did build it. At the peak of the cold war humanity had over 70,000 nukes. Instead of a single world burner, the superpowers built tens of thousands of nuclear weapons of all types and sizes. Hidden in submarines or waiting in bunkers and silos.”

Distributed nuclear arsenals spread across thousands of weapons of varying sizes make nuclear war a more credible threat than Sundial because smaller weapons might plausibly be used in regional conflicts, creating risk of chain reactions of escalation that could trigger existential consequences.

“This also makes them a much more credible threat. Because if people feel they can risk setting off a smaller nuke, they might actually get launched. And we don't know what kind of chain reaction this might trigger.”

The difference between Sundial and the current global nuclear arsenal is not as large as it seems: humanity did not build a single doomsday bomb but instead built a doomsday machine—tens of thousands of distributed weapons that collectively pose equivalent existential risk.

“So in reality the difference between Sundial and what we have today is not even that big. Humanity didn't build a doomsday bomb but a doomsday machine.”

In the 1950s the US began the top secret project Sundial with the goal of creating a single nuclear bomb so powerful it would destroy all of human civilization, and most details about it remain classified.

“In the 1950s the US began the top secret project Sundial, most of it is still classified. The goal: a single nuclear bomb so powerful it would destroy all of human civilization.”

Scientists reacted to Sundial with horror, politicians who were secretly informed responded with disbelief, and even the US Military thought the project was excessive and considered building it a crime against humanity.

“The good news is that Sundial was never built. Most details are still top secret. But we know that scientists reacted with horror and politicians who were secretly informed responded with disbelief. Even the US Military thought this was a bit much... building it considered a crime against humanity.”

Teller celebrated the creation of thermonuclear weapons and claimed he had stolen nuclear fire from the gods and awakened cosmic horrors, but insisted even these weapons were insufficient and his dream was a bomb of almost unlimited power.

“Teller celebrated. In just two years he had enabled the creation of American warheads a hundred times more powerful. He had stolen the nuclear fire from the gods and awoken cosmic horrors but he insisted that it was still not enough. His dream was to have a bomb of almost unlimited power.”

Sundial would have weighed at least 2000 tons, equivalent to a 250-meter-long cargo train, and would explode with the power of at least 10 billion tons of TNT—a number so massive it ceases to be meaningful without graphic demonstration.

“From what we know, Sundial would have weighed at least 2000 tons, as massive as a 250 meter long cargo train. It would explode with the power of at least 10 billion tons of TNT. A number so big it doesn't mean anything anymore.”

Sundial had the energy equivalent of 10 billion tons of TNT, which is three thousand times more destructive than all the bombs dropped during World War II, and if you dropped the Hiroshima bomb every minute, it would take over 15 months to match Sundial's yield.

“Sundial had the energy equivalent of 10 billion tons of TNT. A pyramid of explosives thirteen times taller than the actual Great Pyramid. Three thousand more than all the bombs dropped during World War II. If you dropped the bomb that destroyed Hiroshima every minute, it would take you over 15 months to match Sundial.”

In 1946 the US proposed the Baruch Plan, which promised to eliminate American nuclear weapons, share nuclear technology with the world, and establish an international authority to prevent other nations from building nuclear weapons, but this offer was rejected because the military advantage of nuclear weapons was too valuable to surrender.

“In 1946 the US proposed the Baruch Plan and promised to get rid of their atom bombs, share nuclear technology with the world and set up an international authority to make sure no-one ever builded such weapons again. But the military advantage of nuclear bombs was too great to let go.”

Teller believed that larger and more powerful nuclear bombs were the answer to national security concerns, and he was willing to pay any price for security, making this position extreme even by the standards of the 1950s nuclear establishment, with many scientists appalled by his ideas.

“But for Teller, the bombs were not powerful enough. He was ready to pay any price for security. And to be more secure, to be less afraid, he urged that larger bombs were the answer. Even in the 1950s this was a pretty hot take and many scientists were appalled by his ideas.”

If Sundial were detonated in Nevada, it would create a fireball of pure energy up to 50 kilometers in diameter, larger than the visible horizon, radiating blistering heat at the speed of light, and everything within 400 km would be instantly set on fire—every tree, house, and person.

“For a brief moment a fireball of pure energy appears, up to 50 kilometres in diameter, larger than the visible horizon. It radiates blistering heat at the speed of light. Everything within 400 km is instantly set on fire – every tree, house, person.”

Sundial's blast wave would violently eject the atmosphere above the explosion into space, trigger a magnitude-9 earthquake throughout the United States, and cause the sound to reverberate around the world, with surrounding deserts transformed into fields of glass.

“The surrounding deserts turn into a field of glass. Then comes the blast wave. The atmosphere above the explosion is violently shot into space, a magnitude 9 earthquake shakes the United States while the sound of the blast reverberates around the world.”

Teller's Sundial concept was a world destroyer bomb designed to be so breathtakingly destructive and scary that it made no sense to continue the nuclear arms race, with the rationale being ultimate deterrence: if you attack us or our allies we will destroy the world.

“He wanted to build a world destroyer. Something so breathtakingly destructive, so incredibly scary, that it made no sense to continue playing... In his mind, the rationale was the ultimate deterrence – If you attack us or our allies we will destroy the world.”

When the Soviet Union detonated its own hydrogen bomb, it sparked a new wave of fear that triggered Teller's most ambitious proposal: Project Sundial, a bomb designed to make all other bombs irrelevant and represent the final endpoint of the nuclear arms race.

“When the Soviet Union detonated its own hydrogen bomb, it sparked a new wave of fear. This is where we get the top secret project Sundial. The bomb to make all other bombs irrelevant. The Final Bomb Teller skipped right to the end. The end of the nuclear arms race.”

A single apocalypse weapon presents unsolvable strategic problems: would you press the button if enemy soldiers crossed a distant country's borders or attacked one of your distant bases, or if your rival overthrew a friendly government, or how can you protect an ally with a bomb that would kill them too—these dilemmas made Sundial operationally incoherent despite its theoretical deterrent value.

“A single apocalypse weapon leaves you no wiggle room. Would you press the button if enemy soldiers crossed a distant country's borders or attacked one of your distant bases? Would you end the world if your rival overthrew a friendly government? Can you protect an ally with a bomb that would kill them too?”

The Soviet Union detonated its first atomic bomb in 1949, just three years after the US, catching Americans by complete surprise because Soviet technology was expected to be decades behind but instead had achieved parity.

“Just three years later the Soviet Union detonated their first atom bomb. This caught everyone by complete surprise. The Soviets were not decades behind American technology but had just pulled even.”

The growth of nuclear arsenals was rapid and exponential: in 1946 there were 9 nuclear bombs in the world, by 1950 there were 300, and by 1960 there were 20,000 weapons.

“In 1946 there were just 9 nuclear bombs in the world. In 1950 the number was 300. In 1960 it would be 20,000.”

The first hydrogen bomb was tested in 1952 and instantly erased a Pacific island from the map, and two years later an even larger test detonated a bomb 1,000 times more powerful than the Hiroshima bomb, causing global recoil in horror.

“When this bomb was first tested in 1952 it instantly erased a pacific island from the map. Two years later he tested an even bigger nuke, 1,000 times more powerful than the Hiroshima bomb. The world recoiled in horror.”

A hydrogen bomb functions as a two-stage thermonuclear weapon: a conventional atomic bomb serves as the first stage trigger, detonating next to a capsule of fusion fuel (second stage) enclosed in dense material like lead; the detonation releases X-rays that channel onto the capsule, its surface explodes pushing inward and compressing fusion fuel so violently that it briefly simulates a star.

“A hydrogen bomb is so powerful that it needs a regular atom bomb just to trigger it. It is basically a nuke, the first stage, next to a capsule of fusion fuel, the second stage, encased by dense materials like lead. When the atom bomb is detonated, it releases stupendousungodly amounts of X-rays that get channelled onto the capsule. The capsule's surface explodes, pushing inward and compressing the fusion fuel so violently that for a brief moment it simulates a star.”

Sundial would create an apocalyptic nuclear winter with global temperatures suddenly dropping by 10°C, most water sources becoming contaminated, crops failing everywhere, and most people in the world dying—effectively constituting a single apocalyptic event equivalent to a nuclear war or asteroid strike condensed into one moment.

“Sundial is like a nuclear war happening all at once. But it's more like a giant volcano erupting or an asteroid striking, than a nuclear war. Sundial would bring about an apocalyptic nuclear winter, where global temperatures suddenly drop by 10°C, most water sources would be contaminated and crops would fail everywhere. Most people in the world would die.”