Booze in space: how the universe is absolutely drowning in the hard stuff

July 24, 2017 by Alexander Mackinnon, The Conversation
Mine’s a Star-opramen. Credit: Studioloks

A cold beer on a hot day or a whisky nightcap beside a coal fire. A well earned glass can loosen your thinking until you feel able to pierce the mysteries of life, death, love and identity. In moments like these, alcohol and the cosmic can seem intimately entwined.

So perhaps it should come as no surprise that the universe is awash with alcohol. In the gas that occupies the space between the , the hard stuff is almost all-pervasive. What is it doing there? Is it time to send out some big rockets to start collecting it?

The chemical elements around us reflect the history of the universe and the stars within it. Shortly after the Big Bang, protons were formed throughout the expanding, cooling universe. Protons are the nuclei of hydrogen atoms and building blocks for the nuclei of all the other elements.

These have mostly been manufactured since the Big Bang through nuclear reactions in the hot dense cores of stars. Heavier elements such as lead or gold are only fabricated in rare massive stars or incredibly explosive events.

Lighter ones such as carbon and oxygen are synthesised in the life cycles of very many ordinary stars – including our own sun eventually. Like hydrogen, they are among the most common in the universe. In the vast spaces between the stars, typically 88% of atoms are hydrogen, 10% are helium and the remaining 2% are chiefly carbon and oxygen.

Which is great news for booze enthusiasts. Each molecule of ethanol, the alcohol that gives us so much pleasure, includes nine atoms: two carbon, one oxygen and six hydrogen. Hence the chemical symbol C₂H₆O. It's as if the universe turned itself into a monumental distillery on purpose.

Interstellar intoxication

The spaces between stars are known as the interstellar medium. The famous Orion Nebula is perhaps the best known example. It is the closest region of star formation to Earth and visible to the naked eye – albeit still more than 1,300 light years away.

Yet while we tend to focus on the colourful parts of nebulae like Orion where stars are emerging, this is not where the alcohol is coming from. Emerging stars produce intense ultraviolet radiation, which destroys nearby molecules and makes it harder for new substances to form.

Instead you need to look to the parts of the interstellar medium that appear to astronomers as dark and cloudy, and only dimly illuminated by . The gas in these spaces is extremely cold, slightly less than -260℃, or about 10℃ above absolute zero. This makes it very sluggish.

Ethanol molecule. Credit: Wikimedia

It is also fantastically widely dispersed. At sea level on Earth, by my calculations there are roughly 3x1025 molecules per cubic metre of air – that's a three followed by 25 zeros, an enormously huge number. At passenger jet altitude, circa 36,000ft, the density of molecules is about a third of this value – say 1x1025. We would struggle to breathe outside the aircraft, but that's still quite a lot of gas in absolute terms.

Now compare this to the dark parts of the interstellar medium, where there are typically 100,000,000,000 particles per cubic metre, or 1x1011, and often much less than even that. These atoms seldom come close enough to interact. Yet when they do, they can form molecules less prone to being blown apart by further high-speed collisions than when the same thing happens on Earth.

If an atom of carbon meets an atom of hydrogen, for instance, they can stick together as a molecule called methylidyne (chemical symbol CH). Methylidyne is highly reactive and so is quickly destroyed on Earth, but it is common in the .

Simple molecules like these are more free to encounter other molecules and atoms and slowly build up more complex substances. Sometimes molecules will be destroyed by ultraviolet light from distant stars, but this light can also turn particles into slightly different versions of themselves called ions, thereby slowly expanding the range of molecules that can form.

Soot and fire water

To make a nine-atom molecule such as ethanol in these cool and tenuous conditions might still take an extremely long time – certainly much longer than the seven days you might ferment home brew in the attic, let alone the time it takes to walk to the liquor store.

But there is help at hand from other simple organic molecules, which start sticking together to form grains of dust, something like soot. On the surfaces of these grains, chemical reactions take place much more rapidly because the molecules get held in proximity to them.

It is therefore cool sooty regions, the potential stellar birthplaces of the future, that encourage complex molecules to appear more quickly. We can tell from the distinctive spectrum lines of different particles in these regions that there is water, carbon dioxide, methane and ammonia – but also plenty of ethanol.

Now when I say plenty, you have to bear in mind the vastness of the universe. And we are still only talking about roughly one in every 10m and . Suppose you could travel through interstellar space holding a pint glass, scooping up only alcohol as you moved. To collect enough for a pint of beer you would have to travel about half a million light years – much further than the size of our Milky Way.

In short, there are mind-bogglingly vast quantities of alcohol in outer space. But since it is dispersed over truly enormous distances, the drinks companies can rest easy. It will be a cold day on the sun before we figure out how to collect any of it, I'm sorry to say.

Explore further: Building blocks of life's building blocks come from starlight

Related Stories

Building blocks of life's building blocks come from starlight

October 13, 2016

Life exists in a myriad of wondrous forms, but if you break any organism down to its most basic parts, it's all the same stuff: carbon atoms connected to hydrogen, oxygen, nitrogen and other elements. But how these fundamental ...

Dutch astronomers discover recipe to make cosmic glycerol

June 23, 2017

A team of laboratory astrophysicists from Leiden University (the Netherlands) managed to make glycerol under conditions comparable to those in dark interstellar clouds. They allowed carbon monoxide ice to react with hydrogen ...

When was the first light in the universe?

November 7, 2016

The speed of light gives us an amazing tool for studying the universe. Because light only travels a mere 300,000 kilometers per second, when we see distant objects, we're looking back in time.

Constraining the chemistry of carbon-chain molecules in space

February 27, 2017

The interstellar medium of the Milky Way contains 5-10% of the total mass of the galaxy (excluding its dark matter) and consists primarily of hydrogen gas. There are small but important contributions from other gases as well, ...

The discovery of the molecule Si-C-Si in space

June 29, 2015

The space between stars is not empty—it contains a vast reservoir of diffuse material with about 5-10% of the total mass of our Milky Way galaxy. Most of the material is gas, but about 1% of this mass (quite a lot in astronomical ...

Recommended for you

Did a rogue star change the makeup of our solar system?

July 20, 2018

A team of researchers from the Max-Planck Institute and Queen's University has used new information to test a theory that suggests a rogue star passed close enough to our solar system millions of years ago to change its configuration. ...

Where to search for signs of life on Titan

July 20, 2018

New findings, published in the journal Astrobiology, suggest that large craters are the prime locations in which to find the building blocks of life on Saturn's largest moon, Titan.


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.