Russia Declassifies Video From 1961 of Largest Hydrogen Bomb Ever Detonated

The blast was over 3,000 times bigger than the bomb that destroyed Hiroshima

Tsar Bomba
The mushroom cloud from Tsar Bomba was 42 miles high, about seven times the height of Mount Everest Rosatom

Hydrogen bombs are so destructive, their impact has been described as unthinkable throughout history. Recently declassified Russian footage of the 1961 Tsar Bomba hydrogen bomb test shows why.

The 40-minute documentary, which was posted on YouTube on August 20, shows footage of the largest bomb ever detonated on Earth, Thomas Nilsen reports for the Barents Observer. Video footage shows the blast from several angles, sometimes struggling to show the entire mushroom cloud in the frame. Later, the documentary compares the ice-covered archipelago before the blast to the scorched, red and brown landscape left behind afterward.

The Soviet Union tested the 50-million-ton hydrogen bomb, officially named RDS-220 and nicknamed Tsar Bomba, in late October 1961, Matthew Gault reports for Vice. This test occured during the height of the Cold War, when the Soviet Union and the United States competed to build the largest and most destructive nuclear weapons.

“There was a megatonnage race — who was going to have a bigger bomb,” atomic age historian Robert S. Norris tells the New York Times’ William Broad. “And the Soviets won.”

The bomb was 26 feet long and almost seven feet tall. It was so large that engineers had to modify the bomber aircraft used to carry it by removing the plane’s bomb bay doors and some of its fuel tanks, according to Vice. The documentary adds to other information that Russia has declassified, but nuclear historian Alex Wellerstein tells the New York Times that the video carefully avoids revealing technical details “despite appearing to show the innards.”

The bombers used a parachute to slow Tsar Bomba’s descent to Earth so that they could detonate it relatively high in the atmosphere and reduce its impact on the ground, according to the video. But the blast created a mushroom cloud 42 miles high, about seven times the height of Mount Everest.

"A mushroom cloud forms when an explosion creates a very hot bubble of gas. In the case of a nuclear detonation, the bomb emits a blast of x-rays, which ionize and heat the surrounding air; that hot bubble of gas is known as a fireball,” Lawrence Livermore National Laboratory physicist David Dearborn told Scientific American in 1999 of smaller blasts.

“The fireball from an H-bomb rises so high that it hits the tropopause, the boundary between the troposphere and the stratosphere… [then] the fireball flattens out; it can no longer expand upward, so it expands to the side into an exaggerated mushroom cap.”

But the Tsar Bomba mushroom cloud expanded through the stratosphere and formed its cap in the atmospheric layer above it, the mesosphere.

The Soviet Union detonated Tsar Bomba just months after the construction of the Berlin Wall, and days after a tense 16-hour standoff between U.S. and Soviet troops at the wall’s Checkpoint Charlie.

The Tsar Bomba detonation went in history as the largest bomb ever detonated on Earth. It had a destructive force over 3,000 times as destructive as the bomb used by the U.S. to destroy Hiroshima. And it was three times as large as the biggest bomb ever detonated by the U.S., dubbed Castle Bravo.

The Barents Observer reports that military border guards on Jarfjord Mountain in northern Norway reported seeing the flash. The documentary claims that the flash could be seen about 620 miles away, about the distance between Washington, D.C., and Chicago, Illinois.

The documentary also claims that radiation levels around the blast site were negligible, and it even shows people getting out of their vehicles and walking around the scorched landscape. But as the Barents Observer reports, radioactive fallout swept over Scandinavia and drew international condemnation on the Soviet Union.

But the United States was largely dismissive of the development of the giant bomb, Norris tells the New York Times. Days before the test, the 1961 deputy secretary of defense Roswell Gilpatric said in a speech that American nuclear experts had determined that the value of such a large weapon was “so questionable that it was not worth developing.” Instead, nuclear development continued on a path toward miniaturization, which allowed weapons to be placed on the tips of missiles and transported on trucks and submarines.

From a different perspective, as Carl Sagan wrote in former President Jimmy Carter's farewell address, this same technology has been used to launch rockets into space.

"Nuclear weapons are an expression of one side of our human character,” Sagan wrote at the time. “But there's another side. The same rocket technology that delivers nuclear warheads has also taken us peacefully into space. From that perspective, we see our Earth as it really is—a small and fragile and beautiful blue globe, the only home we have. We see no barriers of race or religion or country. We see the essential unity of our species and our planet. And with faith and common sense, that bright vision will ultimately prevail."

Get the latest stories in your inbox every weekday.