During the height of the Cold War, the U.S. military and atomic scientists embarked on a daring mission to fire nuclear rockets into space.

The goal wasn’t to test the destructive power of nuclear weapons — by the early 1960s, the military had already amassed a formidable arsenal — but rather to study the side effects of nuclear explosions in space.

What they didn’t expect was that their efforts would accidentally trigger a stunning, yet unexpected, phenomenon: a massive crimson aurora visible hundreds of miles away from the test site.

Throughout the 1950s, the U.S. military conducted several nuclear tests, with the goal of understanding the various effects of atomic explosions. However, following an international moratorium on nuclear testing, the military paused these tests for several years.

Here's What They're Not Telling You About Your Retirement

But by the early 1960s, the need to study new phenomena prompted a restart in testing. Military officials were particularly interested in studying the electromagnetic pulse (EMP) effects of nuclear explosions, which could ionize parts of space and potentially cause communications blackouts.

At the time, the military was still uncertain about the full scope of these effects.

In 1961, nuclear testing resumed with the launch of Operation Fishbowl. This operation, initiated by the U.S. military's Defense Atomic Support Agency, involved a series of high-altitude nuclear tests conducted from Johnston Atoll in the Pacific Ocean.

These tests sought to further understand the electromagnetic effects of nuclear explosions, particularly after previous tests, such as 1958’s Operation Argus, had hinted at the potential for EMPs to affect Earth’s magnetic fields.

This Could Be the Most Important Video Gun Owners Watch All Year

Starfish Prime, the third test in the Fishbowl series, would prove to be one of the most significant. On July 9, 1962, a Thor rocket carrying a W49 nuclear warhead was launched from Johnston Atoll. The rocket traveled into the upper atmosphere before detonating approximately 250 miles above the Earth's surface.

However, the test produced a far greater radiation burst than anticipated due to the location of the detonation within Earth’s magnetic fields. The explosion, which was equivalent to 1.4 megatons of TNT, created what NASA described as "an artificial radiation belt," intensifying the natural Van Allen Belt’s electron population by several orders of magnitude.

The immediate effect was startling. The radiation burst triggered an artificial aurora that painted the sky in a vibrant crimson hue. The aurora was visible hundreds of miles away, and it was particularly striking in Hawaii, where residents witnessed a flash of light in the night sky.

Shortly after the explosion, a blackout hit Honolulu, with lights going out and communications failing. Yet, the sky remained illuminated, first with a brilliant crimson light, followed by waves of other colors that lasted several minutes. Witnesses in Hawaii and other locations across the Pacific were left in awe of the rare, man-made aurora.

While the military and scientists were aware that nuclear tests could cause unusual atmospheric phenomena, the intensity of the effect was a surprise. A similar phenomenon had occurred during Operation Argus, though the colors and intensity were far less dramatic.

In both cases, the tests had caused unexpected auroras, but the Starfish Prime test stood out for its spectacular and widespread impact.

The aftermath of the test also had significant consequences. The heightened radiation levels from Starfish Prime knocked out several satellites in the months following the explosion.

One of the most notable casualties was the Telstar 1 communications satellite, which had launched just a day before Starfish Prime.

The radiation damage led to the loss of the satellite, highlighting the far-reaching effects of nuclear explosions in space.

By the fall of 1962, both the United States and the Soviet Union had concluded their upper-atmosphere nuclear tests. The Cuban Missile Crisis later that year pushed both nations to de-escalate their nuclear testing programs.

However, the data gathered from Operation Fishbowl, especially from Starfish Prime, provided valuable insights into the electromagnetic impacts of nuclear explosions, offering scientists a deeper understanding of how such tests could affect both space and Earth’s atmosphere.

While the tests may have been intended for military research, they inadvertently uncovered some of the most spectacular and unexpected consequences of nuclear explosions in space.

Warning: Account balances and purchasing power no longer tell the same story. Know in 2 minutes if your retirement is working for you.