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Is there really alien life on Venus? An expert weighs in

Earlier this week, scientists discovered traces of gas around Venus that could indicate the presence of alien life – we ask an expert how likely it is

Often called the morning or evening star, Venus has enchanted skygazers for thousands of years. The brightest object in the sky after the Sun and Moon, its romantic glow has inspired countless works of poetry and prose, from Homer to Sappho, William Blake to William Wordsworth. In modern Chinese, Japanese, and Korean cultures, it’s known as the metal star, while the Romans named it after the goddess of love, beauty, and fertility.

Earlier this week, scientists detected possible signs of life on Venus. Researchers at MIT and Cardiff University, among others, found traces of phosphine, a rare and toxic gas emitted by some lifeforms on Earth, in the atmosphere of our neighbouring planet, posing the question: is there alien life on Venus? And, if so, what form does it take?

The research itself isn’t a full-on discovery of life on another planet, but the sheer quantity of phosphine (AKA a fishy-smelling gas usually found in pond slime and penguin dung) cannot be explained through any known process. While it is made through some industrial processes, it is also created by anaerobic organisms, including bacteria and microbes, making it an excellent “biosignature” of life.

Despite the size and mass of Venus being relatively similar to Earth, its surface is hostile, with surface temperatures of around 467 celsius, hot enough to melt lead, and pressures equivalent to the seafloor at a depth of one kilometer. If that didn’t sound hellish enough, electrically charged droplets of sulfuric acid circulate through the thick clouds, while a phenomenon called super-rotation whips the upper atmosphere into a vicious global hurricane that sweeps around the planet every four Earth days, with winds of 400 kilometers (250 miles) per hour.

To see what kind of life could possibly exist in this fiery hellscape, Dazed spoke to Dr Alik Kershenbaum, a zoologist at Cambridge University and the author of The Zoologist’s Guide to the Galaxy – what animals on Earth reveal about aliens – and ourselves.

In light of the recent discoveries, how likely is alien life on Venus? Why?

Arik Kershenbaum: We can't say how likely alien life is on Venus. But we can say there’s been a huge thump in the attic, and we’d better go see what it is.

The reason we can’t say whether these discoveries are ‘likely’ to be life is that these hypothetical life forms would have a chemistry we simply don't understand enough – yet. On the one hand, what we know about chemistry and physics doesn’t explain how this gas can be there at all without life. But on the other hand, we don’t yet have a good explanation of how it could be there even if there is life.

What does this new discovery mean for our understanding of alien life?

Arik Kershenbaum: The huge leap here is that we now know we can search out signs of life by looking into the atmospheres of other planets. Scientists have talked about this for a long time, but now we’re seeing it working in practice! We’re going to be looking at a lot more planets now, and we know what to look for. This discovery has also shown us that we can detect chemicals that could indicate lifeforms that are totally different from us – we’re not going to look just for oxygen, that is very much a feature of life on Earth. But also chemicals that might indicate a completely different kind of metabolism. So we’ve widened the search tremendously – rather than just looking for Earth-like life, we know now that we can search for utterly alien lifeforms too.

If there was life on Venus, how would these aliens act? 

Arik Kershenbaum: The model proposed by the scientists in this project suggests that these would be extremely simple, single celled creatures, similar to bacteria, each one floating in a single rain drop of sulphuric acid. When the droplet gets too large, it would rain down – but on Venus, it’s so hot that the liquid would evaporate long before it hit the ground. The cell would dry out, become a “spore”, and then, if it were lucky enough to be blown upwards into cooler layers of the atmosphere again, sulphuric acid would condense around it, and it would come back to life, multiply, and repeat the cycle.

Life living entirely in the atmosphere would have a very difficult time. Anything much larger than a cell wouldn’t be able to stay aloft. Perhaps on other planets, larger creatures could evolve a kind of “balloon” of hydrogen to keep them floating in the clouds. But that’s unlikely on Venus, because such complex life would probably have to evolve on the ground, and then take to the air. Unfortunately, the surface of Venus is so deadly inhospitable, that could never happen. Life on Venus is quite likely to remain very small.

Using what we know about Venus as a planet, how would possible alien life communicate?

Arik Kershenbaum: If there is microscopic life in Venus’s atmosphere, it would be very lonely. The only way to be in contact with other organisms is if your droplet were to merge with another one containing another organism. I’m afraid they’re not going to have too much to talk about. If the life were more complex, however – and it's not at all clear that this is even possible – then many things could happen. For instance, organisms may be bound together with fine filaments, which would both catch air currents to keep them aloft, and could also provide a channel for communication.

“If there is microscopic life in Venus’s atmosphere, it would be very lonely. The only way to be in contact with other organisms is if your droplet were to merge with another one containing another organism” – Arik Kershenbaum

Why is it no longer tenable to claim that there cannot be life beyond earth? 

Arik Kershenbaum: If you look at the trajectory of scientific discovery in the field of astrobiology, you realise that until now, we’ve been stumbling around in a universe we couldn’t see. As we build more and more instruments, like space telescopes and radio telescopes, we realise there’s a lot more out there than we thought. The sheer number of planets that could host life is far, far more than we thought 20 years ago. And now we realise that we can measure the contents of the atmospheres on these planets. So much more information will become available in the next few years – and look how the very first thing we find is a suspicious chemical signature on the planet right next door to us!  Think what will happen when we start scanning the 4,000 other planets we already know about.

In your book, you mention that language and communication will end up being our biggest feature in common with any alien civilisation we encounter. Why?

Arik Kershenbaum: Speculating about possible life on Venus emphasises just how different alien life might be. If it’s living inside concentrated sulphuric acid, there’s no way it‘s going to look like us, or be made of the same material as us. What then will it have in common with us? As I discuss in my book, The Zoologist’s Guide to the Galaxy, what’s in common are the behaviours that all life needs both to survive, and to evolve. Without evolution, life will remain incredibly simple. But if we’re talking about a “civilisation”, then these are creatures that live in groups and cooperate – and that means that they communicate. If they can build a spaceship to come visit us, or even just a radio telescope to send messages to us, they must be able to exchange messages with each other, the meaning of which we would understand – if not the messages themselves.

The Zoologist’s Guide to the Galaxy by Dr Arik Kershenbaum (Viking) will be out September 24