If we discover that intelligent aliens exist it might be because we encounter their technology before we meet them. And if that happens, it is unlikely to result in a happy ending, writes our science and environment correspondent, Professor Tim Coulson
My strong suspicion is that intelligent life exists elsewhere in the universe and that they will have evolved adaptations similar to some those we see in animals on earth. There is little doubt that they will be able to experience the world around though vision, hearing, touch, and taste, processing the information they receive from their sense organs with a brain much as we do before they act on what they experience. But this does not mean their eyes, ears, skin and nose will look like ours.
Perhaps they will have eyes on the end of long protuberances much like stalk-eyed flies do on Earth, ears that can be rotated through 270 degrees to point in different directions much like rabbits, and sexual reproduction where males offer females packets of sperm much as some squid do in the oceans of Earth. They will very probably have dextrous finger-like appendages needed to make tools, but perhaps they are more clawlike than our fingers. Who knows, they might even use a tongue-like organ to help them manipulate objects. Perhaps they communicate with each other by changing their skin colour, much as chameleons and octopus do on Earth.
But if I had to hazard a guess, I’d put my money on them not being enormously athletic. If intelligent aliens have developed technology to visit Earth, it is possible that centuries of reliance on advanced tech means they have become sloth-like: slow, sluggish and largely sedentary. They may be bloated, slow-moving blobs – more Jabba the Hut than Chewbacca, perhaps even using robotic tech to help them move around much like Baron Vladimir Harkonnen does in the book Dune.
I suspect that intelligent life will resemble that seen on Earth because recent scientific breakthroughs have confirmed that the building blocks of life appear to be common in the cosmos.
OSIRIS-REx is an astonishing space craft. It was launched into space in 2016, made its way to an asteroid called Bennu, grabbed some dirt, and made its way back to Earth, arriving home in 2023. Its successful mission was a seriously impressive accomplishment. Analysis of the bits of asteroid it safely returned home confirmed that the molecular building blocks of life are quite common in our galaxy. These molecules self-assembled into you and me on Earth, and so could self-assemble to produce aliens on planets orbiting distant stars. The problem is, travelling between solar systems within the cosmos takes a very long time, and this means sending tech to visit intelligent aliens will be easier than sending people.
What would we do if our space telescopes found signs of life on another planet, including evidence of liquid water and a breathable atmosphere? Because the universe is so vast, we know it would take us centuries, and perhaps millennia, to travel to the alien planet, even if we could. Our closet star system is 4.4 light years away. That means it takes light, travelling at the universe’s maximum speed limit, nearly four and half years to travel from the Alpha Centauri system to Earth. Accelerating large objects to velocities anywhere close to the speed of light is impossible, and achieving a fraction of light’s speed requires enormous amounts of energy. The fastest object humanity has built – the Parker Solar Probe – has achieved a speed of 430,000 miles per hour, or 0.064% of the speed of light. It would take the probe, travelling at its fastest speed, nearly 7,000 years to reach our nearest star system. If we are to send people to a planet outside our solar system, it will be a very long journey indeed.
If science works out how to freeze people for millennia, they could be woken up after the long journey. None of their loved ones or friends back home would be alive, and Earth itself may have changed beyond all recognition. The astronauts would be on their own. Their only option would be to start a distant colony on the planet they had just reached. But they’d have known this before they left. If we can’t put people into stasis for thousands of years, many generations would have to live out their lives on the spaceships making the journey. The descendants of the original astronauts would be very ready to disembark.
It is clear that we are not going to be sending people to planets outside our solar system just to take a look. Instead, we’d be sending them as colonists. I assume that intelligent aliens would do the same if they were to discover Earth. A much easier way to visit a distant planet would be by sending technology. But once again, why would an alien civilisation do that?
There doesn’t seem much point in sending tech part way across the galaxy only for it to send back data it collects thousands of years later. There may be no one left alive to read or interpret the messages. The only reason to send a bit of tech, or people, into deep space would be to colonise a new home. The way to do this, if we could produce the technology, would be to send a spacecraft to a distant habitable world. It would arrive with instructions to grow colonists from DNA, raise these humans, educate them with knowledge from Earth, and send them down to their new home. To help them thrive, it might be necessary to remove any species that might hinder their colonisation. The tech may well be programmed to wipe out any intelligent inhabitants before humans take over. That is what we would do, and I for one am quite pleased we can’t do this. It wouldn’t be our proudest moment.
Given aliens are likely made from the same stuff as us – the building blocks of life brought back to earth by OSIRIS-Rex – they may very well behave like us. Perhaps hi-tech alien spacecraft are already traversing vast tracts of space towards Earth, on a mission to make it a new home for the aliens that built the kit. If that is true, we should treat any alien tech that appears in our solar system with extreme caution.
We might, of course, discover we can build worm holes allowing us to travel to the other side of the cosmos in the blink of an eye, but currently that seems unlikely. Maybe we will discover a way we can travel closer to the speed of life, meaning the journey times for the astronauts would seem short, even though time on earth would run much faster. Einstein showed that time slows as light speed is approached. A nine-year journey from Earth to Alpha Centauri and back from the perspective of a person staying at home would last only a few minutes for the astronauts. For longer missions, the risk remains for the astronauts that a return to earth may not be desirable if civilisation has collapsed or humans have gone extinct.
I really hope we do discover evidence of intelligent aliens. But I hope it is by picking up their radio waves that have travelled across space, rather than their tech. it is frustrating that the universe is so vast, as I’d love to visit other star systems and planets, but perhaps the huge size has its benefits. It makes it challenging for intelligent aliens with colonial intensions to visit us. Given the way we treat other species – even on our own planet – that might be a very good thing.
Professor Tim Coulson is a biologist at the University of Oxford, where he has led both the Zoology and Biology departments. He previously headed Population Biology at Imperial College London and held positions at Cambridge University and the Institute of Zoology London. A highly decorated scientist with awards from major institutions including the Royal Society, he has edited leading journals and served on Government advisory boards. His first book for general readers, “A Universal History of Us” (Penguin Michael Joseph), traces the 13.8-billion-year story from the Big Bang to human consciousness and is available to buy on Amazon.
Main image: Courtesy, Tim Coulson
