So what do you think of this? Recently, astronomers were able to map about 1 billion stars around
us. Sounds impressive, but that’s less than 1% of the total stars in the Milky Way. It’s
statistically impossible for us to be the first intelligent species in the galaxy. There
were advanced civilizations before us. There are some developing a way to communicate with
us right now and there will be more. The only question is: where is everybody?
One thing you can’t take away from human beings is our optimism and hope. All this
time we’ve lived under the starry skies, a lot of people have looked up and thought
we couldn’t possibly be alone in the Universe. And statistics tell us that we probably aren’t.
There are too many worlds out there, and life is too adaptable. In 2017 a group of British
scientists discovered that life developed soon after the planet itself become habitable.
We once thought that the development of life is a highly improbable event, but now this
way of thinking is becoming obsolete.
On the other hand, we’ve been looking for about 70 years for any sign of extraterrestrial
life, or any communication from little green men or whatever they are. And we still have
absolutely nothing to show for it. How is this possible?
That exact question was once asked by famous Italian physicist Enrico Fermi, the creator
of the first ever nuclear reactor. Since then, astronomers and ET enthusiasts alike have
all become familiar with the Fermi Paradox. In simple words: if there absolutely should
be developed civilizations in the Universe, then where is everybody?
The Fermi Paradox has a lot of potential solutions: about 75 to be precise, but today I’ll focus
on the major possible explanations for this troubling absence of aliens around us.
The first group is all about two big ideas: The Rare Earth Hypothesis and the idea of
the Great Filter. They’re closely related to each other, and both can be soul crushing
for those believers out there who want to meet extraterrestrials in person one day.
So please, brace yourself. Can you imagine, how much would have to fall
into place for an advanced civilization to rise to our level – sending radio signals
into space, launching huge telescopes and satellites, searching for exoplanets and other
life. Starting with the qualities of the Sun, neighbor planets, the Earth itself and the
Moon, and ending with our natural curiosity and aching need to reach out into space. Let’s
just say we hit a jackpot in all categories. These requirements combined are called the
Great Filter, and the ability of our home planet to come through it all and win the
biggest lottery in the Universe – is what the Rare Earth Hypothesis is all about.
So what filters are there and what conditions would be good enough for our possible alien
buddies to evolve and develop their civilization? Their sun must be something like our Sun - not
too bright or hot so that whatever planets might orbit around don’t fry to a crisp.
But not too dim or cool – so they’d just be giant, frigid cold spheres. The planet
they live on should be in the habitable zone of their star. One thing to notice is that
we’ve already found planets near our stars that are just like that, so at this point,
all mentioned requirements of the Great Filter should be passable.
The true difficulties start here. For example, there must be something like Jupiter around.
Jupiter is hugely beneficial to us. Its mass attracts all the space debris, meteors and
comets like a giant vacuum cleaner. If not for it, the Earth would be bombarded with
giant space rocks all the time. Another big thing that supports us is our
moon. Did you know that the Moon is the biggest natural satellite in the Solar system in relation
to the size of the planet it’s orbiting? The Moon’s size is a bit under one-third
of the Earth’s, and without a body like this in its orbit, the Earth would be unstable
and unable to support life at all. The size of our planet and its speed of rotation
make an optimal day and night cycle. Our planet has lots of chemical elements, crucial for
the development of life. Most importantly hydrogen, nitrogen, carbon, oxygen, sulfur,
and phosphorus. The last one is quite rare in the galaxy overall and originates only
from supernova explosions, according to recent research from Cardiff University in Wales.
And you think that makes up for a Rare Earth? That’s not even half of the factors, and
we’ll be here all day if we try to go through them all. You get the idea – the Earth is
an extremely rare planet indeed. More important even, is that we’re only
half-way through the Great Filter too. Planets like Earth still must exist in the Milky Way.
Let’s imagine these planets developed life, but they still have to be able to support
it long enough for evolution to get to work. From self-replicating organic molecules like
DNA and RNA to single-cell organisms, then to complex life with distinctive organs, then
to a range of species that can adapt to different environments and inhabit the whole planet,
and finally to an intelligent lifeform that can use tools, think and communicate.
That’s a long, long road that takes at least 4 billion years. All kinds of stuff can happen
through that period! Gamma-ray bursts flashing through the galaxy, extreme ultraviolet radiation,
collisions with other celestial bodies; only if all that misses the planet would we have
a winner. Eventually, it’ll have beings that look at the skies from time to time and
think that they probably aren’t alone in the Universe. This is just how evolution works
- always going for biological complication and the single most effective adaptation tools.
And the tool that stands above all others is intelligence.
But these intelligent folks still won’t be the ultimate winners of this universal
lottery. They still must develop technology to go into space and send signals. The development
of technology is tough enough by itself, but it’s not as tough as the development of
a society that would allow them to live in peace and to aim for the stars.
There’s no way to calculate how often all of this could happen in the Universe, but
let’s be clear: the probability isn’t looking too good. So the Great Filter idea
is a strong candidate to the solution of the Fermi Paradox, though a bitter one.
Another solution is far more optimistic. Aliens are out there, but we just can’t communicate
properly with them. What we use as a means of communication is mostly radio signals but
remember all the steps some abstract intelligent lifeform needs to go through to become an
advanced technological civilization. What if they went through a significantly different
route in technology; one that’s not even comprehensible for us. What if they did so
because their own communication is different than ours? Like through the release of pheromones
and complex movements like insects on Earth, or through a change of color like octopuses
and chameleons, or via smell markers like cats and dogs, for example.
How strange would their high distance communication technology be to us? We probably wouldn’t
even recognize it for what it is, just like they wouldn’t recognize our signals as something
intelligible. In this case, we would be basically invisible to each other, no matter how close
we are on a galactic scale. Another argument is that they must already
be communicating through more advanced technology between different colonies at this point.
But look at this from another point: people still use mail to this date, even though we
have the Internet. Nothing stops aliens from receiving technologically outdated messages,
and nothing stops them from locating where our radio-noisy planet is in the galaxy. But
it still doesn’t happen, so the Fermi Paradox stands firm with its question.
The next solution is far more possible. In basic terms, it proposes that we aren’t
alone, but we are the first to advance our civilization to the needed level of technology.
It’ll take an unimaginable amount of time for us to peak the first signals from ETs.
This argument is even more believable because of how hard it is for life to find its place
in the galaxy. Maybe we’re at the start of the Milky Way and we’re the first to
see it for ourselves! There’s also a funny argument that aliens
are so unlike humans in their way of thinking that they simply don’t want to communicate
with anyone else. Reasons for that could be many things. They might be just grumpy, too
afraid of anything outside of their world. Or maybe they’re able to fulfill all their
needs on their home planet in Utopia, and simply don’t want to explore further. Best
leave it to sci-fi writers, but anyways, it’s worth mentioning that such scenarios are possible,
and they can be quite effective solutions to the Fermi Paradox.
And finally, the solution all fans of UFOs want to believe in – they really are common
in the galaxy, but they can hide from us and maybe they’re already around us. They might
be something we don’t even recognize as aliens, or they’re very good at mimicking
us. Unfortunately, this argument is as interesting as your imagination allows it to be, because
there aren’t any objective restrictions for it. If they are this advanced, then these
possibilities are endless. You know the joke about the chance of meeting
aliens in any given day: it’s exactly 50% - you either meet them or not. This is precisely
what this argument means. And what do you think? What are our chances
to find and meet aliens in the future? Let me know down in the comments! If you learned
something new today, then give this video a like and share it with a friend.
But – hey! – don’t go have lunch with ET just yet! We have over 2,000 cool videos
for you to check out. All you need do is pick the left or right video, click on it, and