Are We Alone In The Universe?

As mankind explores ever further into our universe, a question arises. Are we alone? Are there aliens out there? Or  could it be that humans are the only intelligent creatures in our vast, ever expanding universe. If there are other intelligent beings out there, why haven’t we found them? Or more dauntingly, why haven’t they found us? This statement is daunting since many people believe that there is no way two or more interplanetary civilisations can cooperate. They believe that all interactions with extraterrestrial life will result in warfare. But even so, why hasn’t an intergalactic war started yet? To quote Enrico Fermi “Where is everybody?”

Space is big, really big. In our observable universe, the amount of sun like stars is roughly five billion billion (or 500 quintillion), and there are also roughly 100 billion billion earth like planets orbiting these stars. Let us assume that 1% of these planets, over the  past few billion years have harbored intelligent life, like us on earth. That would leave us with 10 million billion earth like planets with intelligent life in our observable universe alone, and yet we have never encountered a single alien life form, ever. We haven’t even picked up a radio frequency yet. Why is this? The answer lies in the great filter.

The great filter is not a real thing, it is a concept, it  is a way of determining where we stand in relation to other civilisations in the universe. There are three possible ways the great filter applies to us. The first way is we are ahead of the filter, this means we have advanced enough to overcome situations which may have had a negative effect on us as a civilization. An example of this would be the ice age which exterminated the dinosaurs thus wiping out an entire civilisation. This is good because if we are past a certain boundary we may be one of the more advanced civilisations in the universe and therefore we are more likely to invade other less advanced planets first. The second version of the filter is that we have not passed it yet but many other civilisations have. This is not as good since it means there are other civilisations with more advanced technology who could potentially attack and destroy us whenever they wanted. The third and final filter is one that we have not yet passed, while Earth was in its early days as a planet while Earth’s molten crust was cooling other civilisations were thriving. However by now these civilisations have come across an even greater filter, this filter will have completely wiped  out that Alien population leaving it only in relics left behind after whatever caused the mass extinction. However, as other alien populations were dying out we hadn’t reached any filter yet since we’re so far behind many the other civilisations. So we may be the last left in the universe. This is unlikely however it is a possibility. It would be strange to think that the only intelligent creatures in the universe are a pack of apes with smartphones and digital watches. This may be depressing, to know that there’s no one else out there in the universe. However the chances of this being true are incredibly slim, we’re also equally likely to find out get attacked by another alien civilisation, but for now we just have to wait.