For most of human history, the brightest man-made light was just firelight. But around the turn of the century, artificial light came on the scene and the race to create the brightest light ever was on, and it continues to this day. In fact we have created light that is brighter than the sun. Brighter than a nuclear weapon. By tens of millions of times.
TRANSCRIPT:
In the sci-fi classic, The Day The Earth Stood Still, the world is visited by a messenger. A messenger from an alien civilization basically because they saw the flash from our nuclear weapons and were like, “Uh, we need to have a word with you…”
And the words they wanted to have were, of course…
This movie came out in 1951, only 6 years after the atomic bomb, and it obviously reflected the fears and anxieties of a world that had now entered the atomic age.
The atomic bomb was the most awesome force ever unleashed by humans, its light literally vaporized anything in its path. The idea that it was so bright that it got the attention of aliens from across the galaxy probably didn’t feel that far-fetched.
Surely nothing we could make would possibly be brighter than a nuclear explosion.
Actually we have made a brighter light than that. Ten million times brighter than that.
We all know Prometheus as the Titan who stole fire from the gods and gave it to humanity. Zeus got pissed. Chained him to a rock and had an eagle eat his liver only for it to regrow every night.
But Prometheus wasn’t just a pyromaniac. In Greek mythology, he’s a champion of mankind. Some stories even credit him with creating humanity. He was associated with the arts and sciences. Intelligence. Civilization.
Even though these are Greek myths, they reveal something important. Long before we understood chemistry or electricity, we already understood that fire meant progress.
What began as making fire expanded into creating light itself. With each generation, the advancement of what we can accomplish with lights made huge steps. Sometimes very huge steps.
When we talk about light today, we’re really talking about electromagnetic radiation. But visible light is only a tiny slice of that spectrum, between lower-energy infrared and higher-energy X-rays, and gamma rays.
From fire to sunlight, light bulbs to lasers, mankind has pushed its understanding of light, and what we can accomplish with it. By gifting mankind with fire, Promtheus became a figure for human striving. And the fact that scientists are about to make a light septillion times brighter than the sun isn’t terrifying at all.
Fire is a pretty critical part of our evolution. Even in our earliest days, we used it to cook, keep warm, forge weapons, stay up past our bedtimes… Learning to make it ourselves was a huge leap forward in survival.
We were using fire long before we knew how to make it. Early humans probably carried burning branches from wildfires back to their camps. Archaeologists have even found 780,000-year-old fish teeth showing signs of cooking caves near the Jordan River.
Around 400,000 years ago, we start to see evidence that humans were making fire themselves. In eastern England, archaeologists found cracked flint hand axes alongside iron pyrite, also known as fool’s gold. Striking the two together could create sparks.
Another method was the bow drill. A cord wrapped around a wooden spindle let you spin it incredibly fast, creating enough friction to ignite tinder. Usually the bearing block was wood—but sometimes it was bone.
We got a glimpse of this in Cast Away when Tom Hanks rubs a stick in his hands to create fire.
Wilson…
But yes, bone will catch. It actually works surprisingly well. A large molar makes an excellent bearing block, and as Dalem Gumino demonstrated, it’ll take the heat just fine.
Around the first millennium, China was developing gunpowder. The earliest surviving formula appears in a military manual from 1044.
Their weapons had incredible names. “Fire Bird,” “Big Bees Nest,” “Ten Thousand Fire Flying Sand Magic Bomb,” and my favorite, “Flying Incendiary Club for Subjugating Demons.”
Which turns out to be a pretty face melting song by an occultist rock band out of Australia.
Humans also learned to make fire by harnessing sun light.
Through glass or water, you can focus rays of the sun and concentrate them to a targeted area, heating the surface.
You could also bounce sunlight using a reflective— A reflective— Reflective— Stop that.
…a reflective surface to create a burning mirror.
Legend says Archimedes defended Syracuse in 212 BC using giant burning mirrors. Soldiers supposedly reflected sunlight off polished shields, focusing it onto Roman ships until they caught fire.
It’s a pretty genius move! They still lost and Archimedes was killed, and also it might not be true, but it’s a good idea.
Greek researchers and MythBusters both tested it. Yes, they eventually got a wooden ship burning, but only with perfectly sunny weather and a stationary target for at least ten minutes.
Even if the ships didn’t stay still long enough to catch fire a sink, the bright light could still have been blinding or
definitely distracting.
Seriously, stop.
Water works too. Stretch a clear tarp tight enough to hold a shallow pool, and you’ve built a giant magnifying lens capable of burning the wood below.
You could try this at home! I’m not saying you should. But you could.
But you actually should be careful about placing vases or fishbowls on windowsills next to sunlight. An ordinary glass vase sitting in direct sunlight once started a house fire in Tampa, Florida.
Reflected sunight off a curved surface is actually how we light the Olympic torch to this day! There’s a ceremony to light it, then it’s carried like a relay race to the country hosting.
There is a back up flame in case the first went out, which has come in handy a few times. Like in 1976 when the torch went out in the rain. Someone re lit it with a cigarette lighter but that was immediately extinguished an replaced with the official back up.
We stole fire from the gods… mostly so we could stand in front of the refrigerator at 2 a.m. trying to figure out what we’re craving.
But tiny lights weren’t enough. Eventually we wanted lights powerful enough to guide ships through a storm.
Before electricity, a lighthouse was just a really big fire, usually on top of a column.
The most famous was the Lighthouse of Alexandria, built between 284 and 246 BC in Egypt. Standing roughly 350 feet tall, it reflected sunlight by day with a giant mirror and burned a massive fire by night, reportedly visible from nearly 30 miles away.
It survived until an earthquake destroyed it in 1303. 1500 years… that’s a pretty good run.
Fast forward to the Industrial Revolution. In 1853, Professor Frederick Hale Holmes built the first electromagnetic generator capable of continuously powering an arc lamp. Four years later, Trinity House installed the first electric lighthouse.
Arc lamps were used in light house’s until Edison’s incandescent bulbs became the norm in the early 1900s. They used anywhere from 1,000 to 3,000 watts.
Which raises an important question. What’s a watt?
A watt measures power—the rate energy is used. One watt equals one joule of energy per second. But watts don’t tell us how bright something looks. That’s lumens.
A classic 60-watt incandescent bulb produces about 800 lumens. A modern LED produces the same light using around 10 watts. Being able to measure and compare the brightness of light is not just a point of interest, it helps us conserve energy resources.
Then there is the lux which measures the intensity of light on a surface. This has a direct relationship to the distance of the light to an object, not just the brightness of the source.
Candela measures how intense a beam is in one direction. Also known as candlepower, a common wax candle emits 1 candela.
Measuring lux is easy. You just use a handheld light meter in front of the illuminated surface. You see these on film and TV sets a lot with the camera and lighting department. Measuring lumens is trickier since its the output in all directions. Engineers place the light inside a giant sphere that captures every photon bouncing around inside. This is called the IES distribution photometer.
So with light houses in mind, it’s pretty impressive that one of the most powerful light houses measures in at 12 million candelas, reaching as far as 37 miles out to sea. This would be the Créac’h Light house (“kreh-akh”) in France. It uses a metal-halide lamp which is a powerful arc lamp.
But what really makes the lights so powerful is the use of the Fresnel Lens. Instead of using one enormous chunk of glass, the Fresnel lens breaks the lens into concentric rings that bend light the same direction while using far less glass.
But the lens can weigh up to 10 tons, which isn’t easy to turn. Engineers solved it by floating the glass on… Mercury. A lot of mercury.
It’s 14 times more dense than water and has an incredibly high surface tension with minimal friction. These Fresnel lenses would turn on a moat of the liquid metal, but this lead to problems of it own. Chronic exposure could make the light house keepers go insane.
They regularly had to clean impurities in the mercury and found trace amounts covering the entire lighthouse.
William Brown was a lighthouse keeper on Ballenas Island who was repeatedly sent to an asylum because of his alarming behavior in 1905. His wife reported violent behavior and a friend would receive bizarre telegrams from him.
They used to think the trend of madness was caused by extreme isolation but now we know about the dangers of mercury poisoning. Modern lighthouses now turn on a series of ball bearings.
This brings us to searchlights. Think Commissioner Gordon and the bat signal.
In 1893 General Electric unveiled the first search light at measuring at 6 million candlepower at the World’s Columbian Exposition. Most were made with arc lamps backed by a parabolic reflector. This allowed the operator to aim a single powerful beam over long distances.
The worlds strongest man made light beam is the Sky Beam at the Luxor in Las Vegas. This light is made up of 39 Xenon lamps and shoots straight from the top of the casino with 42 billion candlepower.
So powerful is this light source that it has created its own ecosystem. Insects get trapped in the beam. Brazilian free tailed bats travel to eat the bugs, and they in turn are hunted by red tailed hawks. So next time you are ready to hit the tables, consider a little bird watching along the Las Vegas strip.
Search lights have mostly been used for military purposes. During World War I & II, they were used to spot Zeppelins over London, find bombers, and provide light for anti aircraft attacks. They were even used as an artificial moon by bouncing the light off the bottom of clouds.
Since killing each other is the best funded technology, that brings us to our next category of bright lights: nuclear weapons!
In 1896, Henri Becquerel accidentally discovered that uranium emitted energy all by itself. Scientists realized there was an unbelievable amount of energy trapped inside the atom. The question became: how do we get it out?
In 1938, European physicists proved they could split the atom, discovering nuclear fission. Albert Einstein and Leo Szilard immediately warned President Roosevelt that Nazi Germany might build an atomic bomb first. They said the US needed to dial up its own research and beat the Nazis to the bomb. Especially since Germany just gained control of Czech uranium mines. It wasn’t just theory. It was an arms race, and the stakes couldn’t be higher.
The letter worked. When the US entered the war in 1941, 12 different university had contracts for uranium research. In 1942, the Manhattan Project was born. Robert Oppenheimer assembled 200 of the world’s top scientists in the secret atomic city of Los Alamos, New Mexico. For years they studied and tested practical uses of nuclear physics. Their goal was to build the bomb before Hitler did.
On July 16, 1945 they were ready to test their first nuclear bomb, nicknamed Gadget. The gang headed to the Alamogordo Bombing Rage “Jornada del Muerto” which aptly translates to Dead Man’s Journey. Oppenheimer named the test site Trinity and at 5:30 in the morning 425 people in attendance witnessed the first detonation of a nuclear weapon.
The plutonium bomb created about 21,000 kilotons of TNT, far outperforming expectations. After the initial blast, a multicolored cloud grew to 38,000’ high and half a mile across. The blast was so bright it lit up the cockpit of a Navy pilot flying 120 miles away near Albequerqu. He radioed traffic control and was just told “Don’t fly south.” (Nothing to see here!)
Joan Hinton was one of the physicists present and described the scene:
Or, to quote a civilian 150 miles away: “It lighted up the sky like the sun.” Light from the flash could be seen as far as Amarillo, Texas, 280 miles away.
The tower Gadget was sitting on was vaporized and the sand under the explosion fused into greenish glass, the color of jade. It was given the name Trinitite.
The Trinity Test Blast was a huge success and brought America into the atomic age. Less than a month later, Little Boy was dropped on Hiroshima. 3 days after that, the US dropped Fat Man on Nagasaki.
Nuclear weapons aren’t measured in lumens. They’re measured in energy. In this case, kilotons of TNT.
But the brightness of the flash did leave a mark. Literally. Nuclear shadows were left behind in Hiroshima and Nagasaki. The blast bleached and scorched stone everywhere except where a person or object blocked the thermal radiation. Their silhouette remained. The most famous example is Human Shadow Etched in Stone.
What was someone sitting on the steps of Sumitomo Bank is now a shadow of undamaged stone. This happened because crystals expanded from the heat, causing polished stone to become rough. Paint on a building might ignite, except for the place where something blocked the direct heat. Over time these spots faded due to weathering, but steps of the Sumitomo Bank were transferred to the Hiroshima Peace Memorial Museum for preservation.
But even the power of Fat Man was nothing compared to the largest man made explosion in history– The Tsar Bomba.
During the height of the cold war, the Soviet Union created a hydrogen bomb so powerful, it actually made the rival countries go OOOH Do we really want to be doing this?
The atomic game of chicken came to a head on October 30 1961. The bomb was designed by Andrei Sakharov and delivered 50 Megatons of TNT. That’s megatons, not kiltons. That’s over 3,000 times more powerful than Hiroshima.
It was detonated over Novaya Zemlya Island. Witnesses said the brightness of the flash lasted more than one minute and could be seen as far as Greenland and Alaska. The fireball after the flash had a diameter of 5 miles and the mushroom cloud that followed reached 40 miles into the sky, far into the stratosphere. Wood and brick buildings of a village 34 miles away were annihilated. The aircraft that dropped the bomb was 60 miles away before the explosion and was shaken so badly it started losing altitude, but was able to recover and make it home safely. The protective white coating of the plane came back with scorch marks.
There were thermal effects 170 miles away. A settlement known as Dickson 430 miles away felt the shockwaves and windows 560 miles away shattered.
After that the world collectively went, “Maybe we should stop doing this.” In 1963, 126 countries signed the Partial Nuclear Test Ban Treaty, which banned nuclear weapons tests in the atmosphere, outer space, or underwater, for fear of the fallout.
Which is good because the Soviet Union actually designed a 100 Megaton bomb —twice as powerful as the Tsar Bomba— but decided not to test it. The fallout would have been too severe and the pilot would not have survived.
Comparing a nuclear flash to a light bulb doesn’t really work. Most of the energy isn’t even visible light. It’s X-rays, gamma rays, and other radiation far beyond what our eyes can see. These operate at shorter wavelengths and much higher energy.
Today, facilities like Sandia’s Z Machine let scientists simulate the extreme conditions inside nuclear weapons without detonating actual bombs. It can generate temperatures hotter than the center of the Sun and produce intense bursts of X-rays to study high-energy physics safely.
In 2017, physicists at the University of Nebraska created the brightest light ever produced on Earth. It was about a billion times brighter than the surface of the Sun. This can of light is called Light Amplification by Stimulated Emission of Radiation. Or, a laser.
A laser is a highly focused beam of light, all traveling in the same direction and at essentially the same wavelength.
Normally, light bouncing off an object simply scatters, enabling us to see objects. But when the laser becomes bright enough, something strange happens. The scattered light starts behaving like X-rays.
That creates some really exciting possibilities, like detailed medical imaging. It opens up widows for doctors to spot tiny tumors that current technology misses.
The laser created at the University of Nebraska is called the Diocles, named after the ancient Greek Mathematician who wrote On Burning Mirrors around 200 BC.
Since 2017 lasers have gotten more powerful. Researchers at the University of Michigan received a $16 million grant from the US National Science Foundation to develop a laser twice as intense as the Diocles.
Meet ZUES. The National Science Foundations laser facility at the University of Michigan. In was shere in 2025 they developed the most powerful laser in the US at two peta watts. That’s equivalent to two quadrillion watts.
And they are predicting by 2027 they’ll be able to get that number to a zeta watt. That’s a one followed by 21 zeros.
A light this powerful is not a steady beam. In fact the Zues laser only reaches the peta watts for one quadrillionth of a second. The facility is able to accelerate particles, split beams, amplify and compress the laser pulse for highest energy output.
The Central Laser Facility in the UK is developing the Vulcan 20-20 which is predicted to be the next strongest laser in the world. They are claiming it will be sextillion times brighter than the sun. Though construction of the laser is said to take 6 years to complete.
Who knows what black hole we may accidentally but definitely will open up before then?
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