‘Another 50 years of patience’ Accord-

‘Another thirty to fifty years and we will know’

Are we the only ones in the universe? Is that why it is so eerily quiet in our part of the galaxy? Or do alien creatures, lightyears away, feel the warmth of a star just like we do? Lauded Professor of Astrochemistry Ewine van Dishoeck expects that all speculation about this will come to an end before the end of the century.

Text: Sebastiaan van de Water Photography: Bram Belloni

WHAT WAS THERE BEFORE THE BEGINNING?

No six-toed footprint on the moon, not even a cracking signal from the dark void. In the past seventy years, astronauts and astronomers have been unable to find a shred of evidence for the existence of extra-terrestrial life. The only voice that sometimes breaks the silence around our home planet is the echo of our own unanswered question: ‘Hello, is anyone there?’ Nevertheless, Leiden astronomer Ewine van Dishoeck is not disappointed. ‘I am a cautious person. As a student, I thought: “It may take many centuries to answer that big question.” ’ Since then, she has peered through imposing telescopes built on mountain tops. She discovered how and where new planets are born. She organised conferences on the atmospheric fingerprints that life forms leave in the universe.

WILL WE EVER BE ABLE TO TIME TRAVEL?

And just as she predicted, she and her colleagues still cannot say whether extra-terrestrial life exists or not, let alone whether it floats, swims or crawls, or whether it is multicellular, unicellular or noncellular.

But she has since revised her original prognosis. We no longer have to wait for centuries. ‘We are really lucky. We are the first generation with the knowledge and technology to answer this question scientifically. Another thirty to fifty years and we will know.’

Cosmic narcissism

Two powerful instruments are about to change the human view of space forever. In Chile’s bone-dry Atacama Desert, the Extremely Large Telescope (ELT), equipped with a 39-metre-wide mirror, is currently being built. The James Webb Space Telescope is the successor to the legendary Hubble. In addition, the next large space telescope is on the drawing board, designed specifically for the search for extra-terrestrial life, with a launch date around 2050.

‘These new telescopes will allow us to focus on the exoplanets that have been discovered in recent years,’ says Van Dishoeck. ‘Like the Earth-like planet orbiting Proxima Centauri, our neighbouring star.’ A little further away, but just as interesting, are three planets orbiting the star 2MASS J23062928-0502285, also known as TRAPPIST-1.

What makes these planets so exceptional? That is the crux of the matter: they are not exceptional. Just like the Earth is not. The ancient notion that our home planet with its seven seas is a unique celestial body has shown to be cosmic narcissism of the highest order. ‘Water is the most common molecule in space,’ says Van Dishoeck. ‘We have recently discovered that in a region of space where new planets are born, there is enough water floating around for six thousand Atlantic Oceans.’ So, it is possible that the Milky Way Galaxy contains countless planets that are completely covered with the same stuff that falls from our sky in drops.

HOW LONG

WILL WE BE ALONE?

Alien brothers

This is good news, because water is the best conceivable breeding ground for molecules to collide and start the accident called life. That does not mean that swimming takes place on every watery planet. It does not have to. ‘A few hundred billion stars twinkle in the Milky Way alone. We now know that on average they all have at least one planet. Even if only 1 per cent of those stars have an Earth-like planet with liquid water orbiting them, that gives us over a billion potential breeding sites.’

We can tell which planets are the lucky ones by their atmospheres. Living beings are by definition biochemical factories. They take substances from their surroundings and excrete other substances. So, they leave a chemical fingerprint. ‘There are fierce discussions about what those fingerprints might look like,’ says Van Dishoeck. ‘But let me put it this way: if aliens were to look at Earth from one of the TRAPPIST-1 planets with telescopes like the ones we will be building in the coming decades, they will unmistakably conclude that they are not alone.’

It is possible that the discovery of extra-terrestrial life will send shock waves through our society. It is therefore timely that Van Dishoeck joined the Pontifical Academy of Sciences in the summer of 2021. She may soon be explaining to Francis and his cardinals what the approaching discoveries can mean. ‘I hope to meet the Pope soon. I think he is pretty open to the possibility of extra-terrestrial life. He is a chemistry graduate; did you know that?’ says Van Dishoeck.

In his latest encyclical, Fratelli tutti (All Brothers), the supreme pontiff already wrote that in this era in which we discover distant planets, we must not forget the needs of our closest neighbours. ‘I couldn’t agree more,’ says Van Dishoeck. ‘But I did say at the time in the Pontifical Academy: close neighbour is a relative term. Even on distant planets we may find our fratelli.’

CV

EWINE VAN DISHOECK

is Professor of Molecular Astrophysics at Leiden University and scientific director of the Netherlands Research School for Astronomy. From 2018 to 2021, she was President of the International Astronomical Union. In 2021 she became a member of the Pontifical Academy of Sciences. She has received many awards, including a Spinoza Prize in 2000 and the Kavli Prize for Astrophysics in 2018.