Are there aliens, and will I meet one?

I’ve always been interested in discussions about other life forms that might exist in the cosmos. Therefore, it’s not surprising that I enjoy reading about UFOs and the crazy conspiracy theories about possible contact with extraterrestrials. I once even joined SETI, an organisation committed to searching for extraterrestrial intelligence. SETI scans the cosmos for signals and other evidence that intelligent extraterrestrial civilisations exist. I recall logging in regularly to the SETI site to see if any signals had been recorded. After a while, I became disheartened.

Nowadays, I am less inclined to ponder an alien encounter because I figure that the chances are improbable. That is not to say I dismiss the idea that aliens exist. In fact, I think the likelihood of extraterrestrial life is more possible than probable. However, I believe there is a very low probability that I will encounter or bump into an alien from our galaxy or other galaxies at any time soon.  Let’s explore a bit more why I think this way.

I am aware that the Earth is one solar system among countless others in the Milky Way galaxy. The Milky Way is estimated to contain between 100 billion and 400 billion stars, many of which are likely to have their own solar systems. Furthermore, The Milky Way is just one of possibly two trillion galaxies in the observable universe. Given this gigantic number of galaxies, the chances of conditions suitable for life elsewhere must be reasonably high.  

The likelihood of extraterrestrial life becomes more likely when considering the discovery of exoplanets, or planets outside our solar system, situated in regions where conditions may be just right for liquid water, a crucial ingredient for life as we know it. Thousands of these exoplanets have been identified, suggesting that the circumstances that led to life on Earth are not unique. 

The Copernican principle suggests that the Earth and its circumstances are not exceptional on a cosmic scale. If life can arise here, it stands to reason that it could occur elsewhere under similar conditions.  Applying the speculative Drake Equation, conservative estimates suggest we are not alone in the Milky Way. Remember, the Milky Way is only one of trillions of galaxies.

So, with trillions of galaxies and billions of solar systems within each galaxy, you would not be a fool to suggest that life must exist on more than one planet. So why does it seem unfathomable to humans? Well, try to think about it on a scale closer to home; consider the human body. Imagine you’re a microorganism with a reasonable degree of consciousness, living with the liver. The liver comprises thousands of lobules – you live in one of these lobules. To you, the lobules, where you live, are your whole world. You do not realise that there are thousands of other lobules and other places inside the body, like the kidneys, pancreas, or intestines, where different germs live. Each organ is like a different planet from which you are separated without knowing the others exist. 

We humans live on Earth, which is just one “organ” in the vast “body” of the universe. Just like the germ in the liver, we find it hard to grasp the scale of everything beyond our “organ.” There are billions of stars and planets out there, making up galaxies so huge it’s tough for us to even wrap our heads around them. 

The point I am making is that time and space are relative concepts. They’re not the same everywhere and do not mean the same thing to everyone. For example, the space and time experienced by the germ living in the liver might just be a tiny blip relative to a person’s life. Our entire lives are on Earth, and even though we know there’s a vast universe out there, it’s hard to understand what that means.

I am saying that what we see and understand is just a tiny part of everything. Just like the germ might never know about the kidney or the pancreas, there could be things we can’t even begin to imagine in the universe. Time and space are immense, shaping what we think is actual or possible. But just because we can’t see or understand something doesn’t mean it’s not there. Just like there’s more to the body than the liver, there’s so much more to the universe than our Earth.

The chances of meeting an alien are remote. This is because the space that divides planets and galaxies is enormous. To give you a sense of scale, if we travel at the speed of light from Earth to the furthest planet, Neptune, which is 4.3 billion kilometres away, it will take about 4 hours. Light travels at about 299,792 kilometres per second. Now, our galaxy, the Milky Way, is approximately 100,000 to 120,000 light-years in diameter, which is equal to 946 trillion to 1.14 quadrillion kilometres. ​​ This means that if travelling at the speed of light it would take between 100,000 and 120,000 years to travel from one side of the galaxy to the other. That is a very long journey by human standards. This, however, might not be regarded as a long journey for a lifeform from another galaxy. To them, it might be be equivalent to “just around the corner” – it’s all relative you see to our lived reality. Maybe meeting an alien then is not so remote?

Given the vast number of stars, the prevalence of potentially habitable planets, and the Copernican principle, the probability of extraterrestrial life seems plausible and highly likely. The universe has had billions of years for life to emerge and flourish across countless worlds. In this context, the assertion that Earth hosts the only instance of life seems to be the least likely proposition in the vast expanse of space and time. The possibility of us never colliding or encountering aliens remains elusive and unlikely to our human way of thinking. To an alien lifeform, the time and distance that we experience, might be differently perceived.