If there is other life, where is everybody?

Written by TomBurnett88
The question became known as the Fermi Paradox and there are dozens, if not hundreds, of different explanations for why we’re not finding any trace of other civilizations.

The question became known as the Fermi Paradox and there are dozens, if not hundreds, of different explanations for why we’re not finding any trace of other civilizations. Let’s take a look at a few.
Sheer distance
It is sadly more than likely that no human being will ever leave our solar system. Even if we developed light-speed travel it would still take almost five years to reach Proxima-Centuari, the second nearest star after the sun.  A species on the other side of the galaxy could send a signal today and it would take a hundred thousand years to reach us.
That is just in our galaxy.  There are at a hundred billion galaxies.  We will never be able to find aliens in galaxies thousands of trillions of miles away, so it is not a surprise that we don’t hear from any of them.  
It is the same with alien spaceships. They may not have the ability to reach systems beyond their own so of course we wouldn’t pick them up in our system. As for being able to spot them in other systems it is so far just a pipe-dream. Even if they have colonised multiple planets in their system and have regular traffic between them we wouldn’t pick it up.  
It has only been since the 90’s that we’ve been detecting other planets, and only in the last decade we’ve found any the size of Earth in any great number. Detecting a small spaceship when we can only just find the planet it came from is a big ask.
Level of Civilization 
Out of all the countless species that have ever existed on Earth only one can send signals. That’s us. We’ve been around for a few hundred thousand years and we’ve only been doing it for just over a century.  
The other intelligent species in our galaxy may only be at a level comparative to our medieval era or even earlier.  That is even assuming they have the intelligence to get that far – there are probably planets rich with life ruled by animals like dinosaurs which, while impressive, aren’t exactly space-travellers.
That’s at the high end of the life spectrum anyway, most life out there probably consists of single-celled organisms.
They’re hiding from us
For all we know they’ve placed an invisible force-field around our planet that deflects signals and effectively leaves us deaf to the music of ten thousand alien civilizations eagerly conversing. It seems possible, if the galaxy was ruled by a vast coalition of different races, or just one really powerful one that chose to arbitrate the lesser species.
Why would they hide from us? Maybe they don’t feel we’re ready to know they’re there, as far as they’re concerned we are essentially still in a primitive tribal state, butchering each other for tiny shreds of land on a tiny blue speck.  
Maybe we’re in a nature reserve. Maybe, and this one has just occurred to me, they’re afraid of us. They’ve seen what we do to each other on our own planet and how war-like we can be and want nothing to do with us.
They’re all dead 
Our planet periodically goes through mass extinction events where countless species die. There is no good reason it couldn’t happen at an interplanetary level. In the 17th century there was a supernova that exploded so spectacularly that it could be seen in broad daylight here on Earth. Imagine if there had been eight or nine civilisations closer to it.
They wouldn’t have known what hit them until it was too late. For all we know there could have been a massive war that killed thousands of species just hours before we started looking. We could have come to fruition in an era where most of the universe is stagnant (or, in the case of a war, they’re keeping very quiet).
They’re hiding from each other
Possible. If there was a particularly vicious species that exterminated anyone else who reached a certain level then it would be advisable to keep their heads down. You wouldn’t even need that species to exist – most civilisations could have such a fear of war and a long brutal history that they choose to live in peace within their own planet.
We’re the most advanced species in the galaxy
I don’t really like this theory, but it stands to reason that someone has to be.  In this era, it might be us. We could be a cockroach basking in nuclear winter
They don’t care about Space travel
NASA has enough trouble fighting for its budget, maybe the population of other worlds just don’t care enough about space to bother with it. Most of the human race doesn’t really care about space as much as they should.
They wipe themselves out too fast
We’ve come close to throwing ourselves back into the dark ages frequently enough.  We have enough weapons to wipe out our planet. Maybe every species is self-destructive. Maybe every flowering civilization has had just one guy willing to push the button.
Maybe they don’t use the radio frequencies we’re looking for.  Perhaps they don’t use radio at all or they do so on such a narrow frequency that we can’t detect it. They’re probably not looking for us.
They don’t know that space exists
As my final point I’ll finish with this one as it brings us to a full circle.  It has been our desire to touch the stars ever since we first saw them in the night sky.
But what if you never saw the stars? What if the atmosphere was so thick or cloudy that it was impossible to see anything beyond it? What if your planet orbited multiple suns, many stars are in clusters of two or three and it never got dark enough to see beyond them. If no one asked what was beyond the clouds, no one would bother looking.
Of course there are many more theories. It is likely that somewhere in the universe there are civilisations to which at least one of these rules applies.  There probably isn’t a catch-all answer to where everybody is.
But that should never stop us looking.
What do you think? Have your say in the comments section below.
Image: Beckie / Flickr