Life on Earth.
Scientists have been studying it for centuries, creating a timeline from when the first single-cell
beings emerged in primordial waters to today when billions of humans populate the surface.
But there’s one question they’ve never been able to answer with 100% certainty - how
exactly did it begin?
Most scientists think it started from a complex chemical reaction in the water of the early
Earth.
Some argue for a more intelligent hand guiding the process.
The only thing that’s sure is that no one’s sure - and everyone has an opinion.
But what if the origin of life on Earth didn’t actually come from Earth?
Could life on earth be the product of extraterrestrials?
So far, we don’t have any conclusive proof for or against life outside of Earth.
No contact has been made, and no DNA or fossils from other lifeforms has been discovered.
But we’ve only explored a tiny fragment of the universe out there - almost none of
it in person - and the odds that countless planets surrounding countless stars would
have no other planets capable of supporting life since the Big Bang is pretty slim.
And after billions of years of this universe existing, many of those worlds may not exist
anymore.
Asteroids, comets, and other interstellar phenomena can immediately bring a crushing
end to any world’s lifeforms - as the dinosaurs found out the hard way.
But what if the life from those worlds...didn’t stay on those worlds?
The hypothesis is panspermia, which claims that not only does life exist throughout the
universe, but that it gets carried from world to world by traveling objects like asteroids
and comets.
The space dust that gets attached to anything traveling through space - even the spaceships
that humans send to explore the moon and nearby planets - may have microscopic forms of life
in them that travel to other worlds and seed them when they land, creating the building
blocks of future life on those worlds.
But could anything survive in the cold vacuum of space?
Well, we couldn’t, and neither could most animals on Earth.
But when you look at smaller animals, some survive climates that could kill humans in
seconds.
The Pompeii Worm lives deep in hydrothermal vents that can reach up to 175 degrees fahrenheit.
The Flat Bark Beetle, which lives in some of the coldest climates of North America,
produces natural antifreeze chemicals that help it survive the winter and enter into
a sort of stasis - smoothly surviving the coldest parts of the winter while we’re
fighting over the thermostat.
Neither of them could survive space - but that’s not the case for one microscopic
creature.
The name “Water Bear” probably creates cute images of an ursine mammal enjoying a
bath in the river.
But the real thing is much less cuddly - and also less likely to eat you.
Also called a Tardigrade, this tiny organism is the only form of life that seems to be
able to live anywhere, even in the most extreme conditions.
They’ve been found everywhere from deserts to hot springs, and they may even potentially
exist in space - thanks to a crash of a sample from a spaceship on the moon.
These tiny multi-legged creatures can dry up and fall into a state that resembles death,
but when exposed to water even decades later, they spring back to life.
So if life originated from outside Earth, how exactly did it get here?
There are a couple of theories of exactly how those building blocks of life arrived
on our ancient planet, most of them based around interstellar physics.
One theory from a Swedish scientist in 1903 theorizes that the radiation pressure from
stars can send particles through space, but this would only work for the smallest particles
and many if not all would be killed off by the radiation.
But it’s possible that alien bacteria or viruses could survive if shielded from UV
radiation.
The other main theory is that the particles that led to the creation of life were hitchhikers
on rocks, coming into contact with Earth when the rocks crash-landed here.
While we know how asteroids, comets, and meteors travel through the galaxy, this is under far
more extreme conditions than any lifeform has been known to survive - surviving in the
vacuum of space for years on end before crash-landing.
But there is another theory - that the alien lifeforms didn’t come here accidentally.
What if the alien life out there was intelligent and advanced enough that they could have sent
the building blocks of life towards Earth deliberately?
The first possibility of this is accidental transport.
On Earth, there have been countless cases of people throwing trash into the water and
having it be swept somewhere completely different - often endangering animal life in the process.
It’s possible that an alien civilization would have been advanced enough to send waste
products into space and dump them on an uninhabited world - that thanks to the trace DNA on the
waste, evolved into the Earth we know today.
But other theories say that the seeding of Earth may be much more deliberate.
Directed panspermia is the idea that an alien species created life on Earth via transport
of organisms from their world.
The idea of a deliberate seeding of the planet sidesteps a lot of the issues with other theories
- because the aliens would have been able to shield the samples for their trip, eliminating
the threat that the journey through space or the cosmic radiation would kill off the
organisms before they ever reached their target.
The alien species, if advanced enough to send samples into space, would be able to send
them at high speeds that would allow them to reach their destination in a more feasible
time.
So why would aliens want to seed our planet?
The first possible theory is that the aliens were looking to secure and protect life in
space by spreading it among a larger area.
Even the strongest civilization can be felled by a natural disaster or stray comet, and
when life exists on more than one world, it’s insured against the whims of the cosmos.
Of course, that was 3.5 billion years ago, and the odds are good that any alien civilization
that seeded Earth at the dawn of our world would be long gone themselves by now.
But what if they weren’t?
There are many theories about aliens making contact with Earth, but thus far no conclusive
proof has been found - regardless of how many people say they were abducted by a flying
saucer.
But if aliens are out there - and may even have ties to the creation of life on Earth
- then why haven’t they made contact yet?
One theory is that they simply don’t want to - they’re more than happy to just watch.
This is called the Zoo Hypothesis, and it states that we’re all essentially living
in a giant terrarium.
Whatever these aliens are, they have technology far beyond ours and they’re perfectly happy
watching as our still-primitive planet slowly evolves.
If we don’t know about their existence, it’s because they don’t want us to know
- yet.
So are there any problems with this idea?
Just one big one - have you ever tried to get a group of people to agree on anything?
Trying to get ten people to agree on one place to eat is hard enough.
Imagine how difficult it would be to get an entire civilization to agree to keep a secret
forever without any of them breaking the code of silence and broadcasting their existence
to our “human zoo”.
It would have had to last millions of years of humans and their ancestors existing, and
likely countless generations of the aliens not breaking their own protocol.
That’s why many people say the Zoo hypothesis resembles creationism and religious theory
more than panspermia.
But have the aliens truly maintained a hands-off approach all this time?
A popular idea - but maybe not so popular among scientists - is that Earth has been
visited repeatedly by advanced alien civilizations that may have interacted with humans before
recorded history.
Called the Ancient Astronauts theory, it often has ties to various religions - after all,
how many religious texts refer to powerful and mysterious beings descending from the
heavens and performing miracles?
But is there any evidence of these interstellar visits?
If you watch a program called Ancient Aliens - a lot!
This popular documentary-style series looks at evidence of alien interactions with humans,
with a particular focus on early civilizations and the idea that certain technology and buildings
couldn’t have been constructed by pre-industrial humans alone.
They look at mythology of giants and Gods, massive structures like the pyramids that
show up across the world, and technology that seems too advanced for the time like the massive
clockwork Antikythera Mechanism of ancient Greece.
With sixteen seasons and almost two hundred episodes, there are a lot of believers.
But just as many detractors.
The Ancient Astronauts theory - and Ancient Aliens in particular - has been criticized
for using selective evidence and disregarding the contributions of early Native cultures.
The construction methods for megalithic structures like Stonehenge, the Great Pyramids of Egypt,
and the Mayan pyramids have been investigated and largely proven.
While there are still a lot of mysteries surrounding ancient architecture, like the giant stone
spheres of Costa Rica, few of them seem to point to aliens - but that hasn’t stopped
the speculation from growing.
We don’t know for sure if aliens have visited Earth - but there’s a chance that their
DNA is still with us.
We might all be descended from aliens, if their organisms seeded our world eons ago.
The most likely scenario, if we evolved from alien microorganisms, is that we’re so radically
different from the original species by now that there would be no similarity anymore.
If an alien species did seed Earth deliberately, then the odds are it didn’t seed Earth with
the most advanced form of life on its planet but one of the smallest and easiest to transport.
The continuum of life on Earth indicates life likely started with microorganisms swimming
in the water before turning into larger forms of life and eventually heading onto land - a
far cry from the aliens who might have organized Earth’s seeding.
But could humanity’s ties to alien DNA be a lot more recent?
Many proponents of the Ancient Astronauts theory suggest that the aliens may have continued
to visit Earth up until the early days of humanity, and may have actually bred with
humans - leaving traces of their DNA in ours.
While the idea of aliens on a pleasure cruise looking for some exotic party times may be
relatable - especially if they have common DNA with those party kids who hit Cancun every
Spring Break - there are a lot of holes in the theory.
The aliens would have to still be around and in a similar shape billions of years after
Earth was first seeded, and they would have to be genetically compatible with humans despite
those billions of years of evolution.
So, no, it’s not very likely that your great-great-great-great-great grandpa was an alien.
But that doesn’t mean this kind of interbreeding between humans and their distant relatives
isn’t possible.
Recent studies indicate that human fossils have traces of DNA from ancient humans that
preceded Homo Sapiens.
The more famous Neanderthals are in there, but so are an extinct species of archaic humans
we know relatively little about - the Denisovans.
Only identified in 2010 in Siberia, they’ve been identified from a few bones and teeth
that are distinct from other species.
When ancient genomes were sequenced for the first time, scientists found fragments of
genetic code that didn’t match up with Homo Sapiens.
Neanderthals were quickly identified - in fact, it’s estimated that most humans besides
Africans have up to four percent of trace Neanderthal DNA in their genome.
No one knows exactly what populations of ancient humans may be lurking in the recesses of the
human genome, both ancient and modern.
What we do know is that modern humans are a complex mix of influences that made us what
we are.
Could one of those influences be from beyond our solar system?
We don’t have proof of that yet - but the human genome is a mystery, and we don’t
have proof that it’s impossible either.
For more on alien visitors, check out “This Will Happen When the Govt Confirms Aliens
Exist”, or watch “How Did the Dinosaurs Die” for more on the chaos objects from
space can cause.