When we think of the word ‘universe’, we should probably think of hydrogen.
Hydrogen is a colourless, odourless, tasteless, but highly flammable gas. It’s the element that makes up 74% of all ordinary matter, lights the stars and in doing so illuminates the universe.
All hydrogen was formed immediately following the Big Bang, as quarks coalesced into atoms in the first few seconds of the universe. Hydrogen is the simplest atom to make with just one proton and one electron, and because of that simplicity a lot of it was made.
Along with helium and trace amounts of other elements, it formed huge clouds in space and under the influence of their own gravity, they slowly turned into the galaxies, dust clouds, and stars that are strewn throughout the universe.
Stars are both made from and fuelled by hydrogen.
When a cloud of hydrogen coalesces into a dense ball and passes a critical mass, it’s own gravitational weight fuses together hydrogen and other atoms at its core. They release huge amounts of heat, light, and waste products like iron. In our Sun, a medium sized star, 600 tons of hydrogen are fused in every second.
Through this process, stars heat and illuminate the universe.
After billions of years waste products like iron build up, and a star will reach the end of its life. Many stars then erupt in a giant explosion. The resulting shockwave creates a multicoloured gas cloud called a nebula, and they look absolutely stunning.
Nebulae are also known as ‘stellar nurseries’, because even though they are the remnants of dead stars, they still contain enough hydrogen to form the next generation of stars, as well as the planets that orbit them.
Our own Sun, as well as many of the stars nearest to us were born inside of a long-gone, ancient nebulae of unknown shape and colour.
It follows that almost everything around you, from hands to the metals in your phone, was once hydrogen gas before it was transformed by a long-dead star. (We go into detail about how this happened in our two-part article called The Story of Your Atoms).
Most of the material that formed our solar system coalesced into the Sun and the planets known as the gas giants. It’s why Jupiter, Saturn, Neptune, and Uranus are about all 90% hydrogen.
But down on Earth, we still have plenty of hydrogen and we’ve invented a number of creative uses for it.
When hydrogen burns, it gives off very few pollutants and zero carbon dioxide. Some energy companies are promoting it as an emissions-free alternative to gasoline.
We sometimes use it as rocket fuel, but it takes up a lot of volume for its weight, so we cool it into a liquid to fit more into a container. But this usually creates its own complications. The containers have to have thick heat-resistant walls that must be maintained, which makes it an expensive fuel to use.
Considering that hydrogen is literally rocket fuel, it’s bizarre that it was also used last century as the gas that gave lift to airships and zeppelins.
Predictably enough, it caused a massive explosion in the airship Hindenburg in 1937 when it was lit by a static spark.
Nowadays we use helium to lift blimps and airships, even though it’s rarer, more expensive, and weighs more than hydrogen. But it also doesn’t explode.
But in 1937, the production of helium was monopolised by the United States, who refused to export it to any other country (including the German-based company that made the Hindenburg) under the reasonable concern that it might be used for military purposes, considering WWII erupted just 2 years later.
So although the zeppelin engineers at the time were aware of the explosiveness of hydrogen, they decided to go ahead with it as it was the only option available.
The fact that the substance that we are made from was once rocket fuel is a bizarre and highly conceptual thing to think about. It speaks to the fact that the universe is constantly evolving and that we are a part of that process.