Hydrogen
Hydrogen is the building block of the universe. All atoms can be traced back to hydrogen.
The First-Born Atom
Hydrogen was born within 3 minutes of the Big Bang. In that time, the cosmos cooled just enough to allow protons to hook up with wandering electrons. Today, every hydrogen atom is 13.8 billion years old. Most atoms in the universe are hydrogen. The atomic population consists of 91% hydrogen, 8% helium, and 1% other elements. By weight, hydrogen is 75% of all matter in the universe.
The hydrogen atoms in my morning coffee have made quite the cosmic journey before landing in my cup. They drifted through interstellar space, flowed through Earth’s water cycle, and were drawn into a coffee bean by a sunlit leaf before being poured into my cup. As I sip, I partake of atoms that are nearly as old as time itself. That atom will continue to be a part of untold stories in eons to come. It may become part of a distant ocean, a cloud on another world, or the vaporous breath of a being yet to exist. I am just passing through, an event in a cosmic story written in the ink of hydrogen.
The Universe Runs on Hydrogen
The Sun is one among a billion trillion suns scattered across the observable universe. Our sun converts 600 million tons of hydrogen into helium every second through nuclear fusion. The energy released is equivalent to millions of Hiroshima-sized bombs every second. This stellar furnace operates at a temperature of 15 million Kelvin in its core. Hydrogen nuclei move fast at this temperature. But not fast enough to overcome the coulombic barrier. The repulsion is still too high. Enter quantum tunneling. Once two protons are within a few femtometers of each other, they may tunnel through the barrier. Quantum tunneling is the improbable gateway through which further creation of heavier atoms beyond hydrogen happens.
There is light. And heat. Hydrogen fusion powers the universe. Through fusion, hydrogen is converted into helium, as well as carbon and oxygen. Hydrogen is the source from which the atomic family emerges. That, in turn, seeds future stars and planets. The hydrogen in water, glucose, and amino acids becomes part of the flexible scaffolding on which life is built. Hydrogen is the fuel that gets consumed, allowing everything else to come into being. However, that gives the remaining hydrogen a chance to participate in something richer than being hydrogen alone.
The energy represents 0.7% of the mass converted in proton-proton fusion. Stars spend 90% of their lives burning hydrogen fuel. Our Sun is at the halfway mark of its lifecycle and has enough hydrogen to continue for another 5 billion years. As long as there is hydrogen, there is hope. The sunlight hitting my face right through the window began as a result of hydrogen fusion. The energy from hydrogen fusion takes 100,000 to 1 million years to travel, via a random walk of photons, from the Sun's core to its surface, and then 8 minutes to reach my face.
Humanity is trying to bottle a star. Tokamaks and stellarators are devices under development that utilize ionized hydrogen and magnetic fields to generate a net positive energy output from fusion. One gram of hydrogen fuel is equivalent to approximately 11 tons of coal. But there are several challenges. Earthbound fusion requires temperatures nearly 7 times hotter than the Sun's core because we lack the Sun's immense gravitational pressure. Plasma is difficult to confine. Materials must withstand neutron bombardment and extreme heat.
The ITER experimental project aims to demonstrate 500 megawatts of energy production from just 50 megawatts of input—a 10-fold energy gain. Commonwealth Fusion Systems (CFS) — spin-out from MIT — secured a landmark deal: Google will purchase 200 MW of future fusion power from their ARC/SPARC project planned for the 2030s. The SPARC tokamak is projected to demonstrate net fusion energy by 2027. ARC, its successor, aims to deliver fusion electricity. If we succeed in bottling a star, we unlock not just abundant clean energy but also achieve a symbolic return to our cosmic origin. What powers human creations would intrinsically be the same as what powers creation itself.
Our Body and Mind Run on Hydrogen
Hydrogen is 63% of all atoms in the body and approximately 10% of body weight. Hydrogen is in bodily water, fats, amino acids, enzymes, cell membranes, and hormones. Hydrogen ions regulate pH, which affects enzyme activity and blood chemistry. Through pH, hydrogen ions also subtly modulate neuronal excitability and the chemistry of consciousness. What fires up the stars also fires up the brain.
Mitochondria produce ATP because of hydrogen ions flowing across their membrane. Energy production can be seen as a proton-driven motor. The binding of neurotransmitters to receptors utilizes hydrogen bonding, which is not as permanent as covalent bonds, but is selective and reversible, allowing for the dynamics of life to run smoothly. DNA's double helix structure depends on hydrogen bonds to maintain its shape. We digest food with the help of hydrogen ions in the 1.5 to 3 liters of gastric acid that we produce daily.
The fuel of the sun has now become fuel for consciousness. The nuclear fury of hydrogen has now been tamed to flicker as cognition. The humble hydrogen is the life of the Sun, and the origin of every atom in the architecture of life. Hydrogen, that once burned alone, now quietly animates what it has begotten.
The Day Hydrogen Fell From the Sky
The Hindenburg disaster of 1937 consumed 7 million cubic feet of hydrogen in just 32 seconds, killing 36 of 97 people onboard and ending passenger airship travel forever. It was one of the first disasters captured in real-time by the media. The tragedy was broadcast live on the radio, with reporter Herbert Morrison's cry "Oh, the humanity!" becoming one of history's most famous disaster recordings.
The 245-ton German airship's tail may have been leaking hydrogen that ignited due to static discharge, creating a fireball that reached temperatures of 2,000°C. Hydrogen itself is not flammable. It took the oxygen and the spark. That's how destructive fires work, don't they? The visible flames were not from the hydrogen itself, but from the ship's fabric skin and components. Zeppelins made 2,000 flights over 30 years, without a single injury, and then the era of airships ended in a few fiery minutes.
Ironically, the U.S. had the world’s largest helium reserves at the time, but refused to sell helium to Germany, which was one reason the Hindenburg used hydrogen instead. Thereafter, blimps have used helium. The switch to helium sacrificed about 8% of lifting power, but brought vastly improved safety. Although helium is slightly larger than hydrogen in molecular terms, its inert nature and monatomic form make it more challenging to contain. Specialized materials and containment systems had to be developed to handle helium without excessive leakage.
The story of hydrogen didn’t end with the Hindenburg. The allure of hydrogen has drawn us back. We are learning to tame hydrogen again — not for airships, but as a clean energy carrier. It’s used in fuel cells for vehicles and backup power, as well as in research on portable and industrial energy systems. NASA has relied on liquid hydrogen as rocket fuel for decades. Efforts to expand its role in the energy transition are gaining momentum. The focus is on how to produce and handle it safely and efficiently at scale.
How Hydrogen Puts Food on the Table
Crops to feed the growing population in the nineteenth century needed bioavailable nitrogen to grow. Farmers relied on manure, guano, and saltpeter, which could not scale with rising demand. A crisis loomed.
Hydrogen came to the rescue.
German chemist Fritz Haber discovered a method for combining nitrogen with hydrogen (from water or methane) to form ammonia (NH₃) at ~500°C and 150–200 atmospheres, using an iron catalyst. It was a chemical miracle. Carl Bosch, working at BASF, helped perform the engineering feat of designing reactors that could manage heat, pressure, and corrosion while ensuring continuous operation.
Germany went on to weaponize the process for explosives during World War I. Ammonia was converted into nitric acid, which was then converted into TNT. In peacetime, the Haber-Bosch process revolutionized agriculture. Today, it consumes 70 million tons of hydrogen annually and produces fertilizers that help feed half the global population. Without hydrogen-based fertilizers, the Earth could only sustain about 4 billion people, not the 8 billion it sustains today. However, the process is energy-intensive, consuming 1-2% of the world's energy.
Hydrogen, produced through the Haber-Bosch process, turned nitrogen from the air into both bread and bombs.
Hydrogen-fueled Dreams
Hydrogen helps make cleaner fossil fuels that move the world. Petroleum refineries use hydrogen to remove sulfur from crude oil, producing cleaner gasoline for over 1.4 billion vehicles worldwide.
But hydrogen’s future may lie beyond oil.
Hydrogen fuel cells can achieve efficiencies of up to 60% (compared to 20% for internal combustion engines, or ICE), emitting only water vapor as a byproduct. Toyota’s Mirai can travel 400 miles on a tank of hydrogen and refuel in just three minutes, combining the range of gasoline with the cleanliness of electricity.
Today, 95% of industrial hydrogen is still produced from natural gas, via steam methane reforming, a carbon-emitting process. This “gray hydrogen” is neither green nor clean. The promise lies in green hydrogen, made by splitting water using renewable electricity to power electrolysis. Hydrogen can be used as a fuel, a feedstock, or even an alternative to batteries, storing excess solar or wind power in a chemical form.
If scaled, hydrogen could become a cornerstone of long-term energy storage and decarbonization. Japan has already invested $3.4 billion in hydrogen infrastructure, aiming to make hydrogen a pillar of a carbon-free energy economy.
But the dreams stretch even further.
The energy-to-weight ratio of hydrogen beats any chemical fuel. That makes it ideal for deep-space exploration. Future propulsion systems may utilize hydrogen isotopes in fusion rockets capable of reaching 10% the speed of light, which is fast enough for interstellar missions. At present, NASA’s Space Launch System consumes 537,000 gallons of liquid hydrogen per launch.
Water ice on the Moon, Mars, or asteroids could serve as fuel depots for interplanetary travel. Europa, one of Jupiter’s moons, holds twice as much water as all of Earth’s oceans — a distant reservoir of hydrogen for the next generation of explorers. One can dream. Such is the potential of hydrogen.
Back on Earth, private companies are betting on hydrogen-powered aircraft. Airbus is developing four 2 MW fuel-cell electric engines for its next-generation hydrogen aircraft. The technical hurdles are real: hydrogen infrastructure, onboard storage, and regulatory frameworks all need to mature. But the ambition remains. Hydrogen is the most abundant element in the universe and is unmatched in its energy-to-weight ratio. It could work.
Hydrogen came from stars and may one day carry us back to them. Is it the ghost of Hindenburg still holding us back?
Hydrogen’s Hidden Powers
Hydrogen enables the most precise timekeeping humans have ever achieved. Hydrogen masers, based on the energy transitions of single hydrogen atoms, are accurate to one second in 30 million years. These quantum clocks exploit hydrogen’s unmatched simplicity — it’s the only atom whose quantum behavior can be calculated exactly.
Its spectral signature — the 21-centimeter line — allows astronomers to map distant galaxies, measure cosmic expansion, and track the rotation of the Milky Way.
Hydrogen's quantum properties also enable MRI machines, where hydrogen atoms in the body's tissues respond to magnetic fields, creating detailed medical images without radiation exposure.
Hydrogen bonding between water molecules creates a surface tension strong enough for insects to walk on water. It enables plants to transport nutrients up to 100 feet against the force of gravity. These same bonds give water its high boiling point of 100°C. Without hydrogen's specific bonding behavior, water would boil at -80°C, making liquid water and life impossible. Hydrogen bonds also stabilize protein structures and enable DNA replication, with each human cell containing 6 billion hydrogen-bonded base pairs. Hydrogen bonding makes life possible on our planet.
Some bacteria can metabolize pure hydrogen gas, representing one of Earth's most ancient energy pathways, dating back 3.5 billion years. These hydrogenotrophs have been discovered in underground aquifers and near deep-sea hydrothermal vents. They can survive on hydrogen concentrations as low as 0.1 parts per million, suggesting life could exist in hydrogen-rich environments throughout the universe. Their metabolism produces methane, which potentially explains the mysterious methane signatures detected on Mars. Hydrogen was the first fuel of life, and may still sustain life elsewhere.
The Bottom Line: Hydrogen is present in everything — from the building blocks of matter to the flicker of awareness, from the fusion cores of stars to the spark of conscious thought. Without hydrogen, there would be nothing. All things seen and unseen, in all their unfolding complexity, have emerged from its simplicity — and are still sustained by it. Its story is the first chapter in the grand narrative of matter.
Images
- Hubble image of Caldwell 22, a planetary nebula located approximately 2,500 light-years from Earth, which represents a stage in the evolution of stars like our Sun as they exhaust their fuel. The process begins when, after billions of years of nuclear fusion, the star starts to shut down. Gravity (no longer balanced by the outward pressure created by nuclear fusion) compresses the stellar core. The star’s outer layers of gas puff away into space, creating a planetary nebula. One day, the Sun, which is halfway through its 10-billion-year lifespan, will meet a similar fate.
- The fuel cell is the reverse of water electrolysis, producing just water and heat. Energy from sustainable sources could be used to produce hydrogen by electrolysis. That would give us a clean, portable energy cycle. Image: Emma Ambrogi via Wikimedia Commons
- MRI utilizes the magnetic properties of hydrogen atoms in water to produce detailed images of the body. When in a magnetic field, hydrogen atoms align their spins. Radio frequency pulses excite these atoms, causing them to emit signals that are detected to form images. MRI, a non-invasive, radiation-free technique, is safer than X-rays or CT scans. Image: SumaLateral Whole Brain Image by National Institutes of Health (NIH)
- Of the 97 people onboard the transatlantic flight, 62 survived. Remarkably, the Hindenburg featured an air-locked “smoking room”. Zeppelins made 2,000 flights over 30 years, without a single injury, and then the era of airships ended in a few fiery minutes. Image: Hindeburg Disaster by History In An Hour
- Cavendish discovered hydrogen in 1766 by adding acids to metals like zinc and iron. Cavendish also conducted the famous experiment to "weigh the Earth" using a torsion balance to measure gravitational force. He determined Earth's density and mass. Cavendish was famously shy and reclusive. He rarely spoke, avoided social gatherings, and communicated with his female servants only through notes. Despite this, he was incredibly wealthy (inheriting a fortune) and spent much of it on scientific equipment. Image: from Wellcome Collection
- Bottle-like cryostat that houses NASA's Wide-field Infrared Survey Explorer, or WISE, mission and contains frozen hydrogen that cools the instrument. WISE discovered thousands of minor planets and numerous star clusters. Image: JPL
- The GM Electrovan used a fuel cell produced by Union Carbide, which was fueled by both super-cooled liquid hydrogen and liquid oxygen. Image: 10-28-1966 First Hydrogen Fuel Cell Car by Hugo-90