Have you ever wondered that if aliens do exist why haven't we seen them yet?
It's not at all unreasonable to expect them to have shown up already. So, let's discuss why they haven't, and also why it would be an awful thing if we do find alien life, shall we?

Planets are quite common in the Universe. In our galaxy, The Milky Way, alone, we have at least 500B planets including at least 10B Earth-like planets. So life as we know it should be a rather common occurrence in our galaxy, but somehow it doesn't seem that way.

This is the Fermi Paradox. It simply states that there is a contradiction between how we have no evidence of extraterrestrial life and how it should be abundant throughout the Universe based upon our logical estimations. We can't be alone in the whole Universe... or can we be?

Over the years, a lot of people have come up with their own explanations to this paradox. Our planet is only 4.5B years old, whereas the Universe is 13.8B years old. Thousands of civilisations could have existed before our planet was even formed and are most, if not all,

now dead. And even if they are still around, there is no way we can guarantee that we would be able to answer their calls just yet. If they're a more advanced civilisation, they could be using an entirely different form of communication.

And for all the pride we take in our intelligence, we have been listening for only about a century. So, they could be trying to contact us but we just cannot hear it because of our primitive technology.
Or maybe intelligent life is not as common in the Universe as we think.

There could be life beyond of our little moist rock but they might not be advanced enough to contact us or to even be noticed by us. So, our galaxy could be filled with microscopic life but none of them would be as intelligent and complex as us.

This is where the Great Filter comes in! The Great Filter is a situation or a problem that a species just cannot overcome; one that leads to their inevitable doom. If intelligent life or even life, for that matter, is quite rare then it means that the Great Filter is behind us.

The reason that we haven't seen aliens yet could simply be that they didn't make it as far as we have. This means that one of the stages in our development as a species was nearly impossible to pass, but we did it, and now progress is ours. But what if the Filter isn't behind us?

This is why finding alien life, or even the ruins of an alien civilisation would be a terrible discovery. If our galaxy is teeming with life, albeit we haven't discovered it, it would mean that the Great Filter is in front of us, and it might just be one we won't be able to pass.

The Great Filter could be anything. For example, finding ruins of a modern alien civilisation would mean that the native species developed technology that led to its own destruction. And as of now we do have the technology to destroy our entire planet: Nuclear Weaponry.

Or the dominant species of the planet irreversibly change the composition of its atmosphere and make its own planet uninhabitable for itself. We don't have to look far for this example, either. We're doing the same thing with ours. Global Warming could be our Great Filter.

Our best chance at survival would be that there are no, or just a few, intelligent life forms out there. It would be better for us if we have already passed the great filter, and to not have to pass one in the near future. But things sometimes seem to say otherwise.

In case the Great Filter is indeed ahead of us, it would benefit all of us to combat all the existing problems that could turn into the Great Filter. Development of technology is inevitable, but a more responsible approach needs to be employed.

Global warming is one of the biggest problems of today, and one that will most likely be the Great Filter we would not be able to pass through.

As a species, we will always strive to survive. Looking for new habitable worlds while preserving this one is the best thing we can do for ourselves. The only way out is up. If the Great Filter is ahead of us, then we must pass it!

We must pass it, for we might be one of the very few species that have made it this far. We only have to find out how far we can go