By George Thomas
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Many people will have recently heard of the potential discovery of an artefact of alien intelligence around the star KIC 8462852 (If you haven’t, read here for more info http://www.iflscience.com/have-we-really-discovered-huge-alien-megastructure-around-star). Further recent study of the star has ruled this out as an option, but it was an interesting idea. With that said, I want to talk about the potential implications of intelligent, highly advanced, alien life existing in our Galaxy.
The object that had been speculated as a potential sign of an advanced civilisation is called a ‘Dyson sphere’. Put simply, the idea is that you surround a star in a dome of solar panels to absorb the light energy emitted, to provide enough fuel to sustain your highly advanced alien race. However, surrounding the entire star in a dome isn’t very practical, for multiple reasons, but lots of spaced out satellites could work as a good alternative source for harnessing power. This concept is known as a ‘Dyson bubble’. The presence of a structure like this around KIC 8462852 would have explained the initial observations, but other explanations such as lots of comets are far more likely.
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| Illustration of a Dyson Bubble Credit: Wikipedia |
A lot of news outlets had spoken about us potentially finding alien life, but what if there were aliens; would they have found us? Of course, we haven’t got a giant structure surrounding the Sun to give ourselves away, but one way we have been giving ourselves away is in how, at least for the last 100 years, we’ve been broadcasting radio waves across the Galaxy. Unfortunately the radio waves will have become so spread out in their travel that our signal will be indistinguishable from background noise beyond a few lightyears away. Also, in the case of KIC 8462852, the star is too far away (about 1500 lightyears) for our radio waves to have travelled to any potential life stationed there. Unless the species had spread out to stars much closer to our Sun, they wouldn’t have had time to pick up any signs of technology that we may be giving off.
There is, however, the Earth itself, which has been harbouring life for the last few billion years. Any intelligent beings looking out at the Galaxy with the technology to detect our pale blue dot will have been able to tell that we’re sitting very comfortably in the habitable zone around the Sun. This is especially true of any species capable of building a Dyson bubble, which begs the question: if there is an advanced civilisation relatively nearby, why haven’t they come to us?
The answer, much to the dismay of sci-fi fans, is probably the restrictions of travel through space. Although there are various theories about using wormholes to avoid technically travelling from one point to another at speeds faster than light, the entirety of physics thus far points to a constant restriction: information cannot travel faster than the speed of light.
This isn’t definitely the reason, though. An optimistic view could be that life is so overly abundant in the universe that no alien species has bothered to come to us yet. But, as said, this is very optimistic, and the inability to travel to our stellar neighbours in a time considered reasonable compared to the human life span is a far more likely reason. If they have found us, and can reach us, then they’re making an active choice not to engage with us, which would be a curious decision in itself.
This means that although we may in future discover advanced civilisations dotted around our
galaxy, we may never be able to reach them. We may not be alone in the Universe, but we
may well be too far away to ever see our neighbours.
galaxy, we may never be able to reach them. We may not be alone in the Universe, but we
may well be too far away to ever see our neighbours.