Something is emerging
from the Mariana Trench,
and it does not belong on this planet.
If aliens lived
in the deepest place in the ocean,
There’s a reason why the idea
of aliens living at the bottom of the sea
keeps popping up in popular culture.
Many of us are far more afraid
of what lies down there
than whatever is looking at us
from up in space.
After all, 80% of the ocean
is still unmapped and unexplored.
We have better maps of the Moon,
Mars and Venus
than we do of our seafloor.
The most mysterious part of our oceans
is the Mariana Trench.
Its deepest point, the Challenger Deep,
stretches 11 km (7 mi) down.
The Mariana Trench is anything
but a great vacation spot.
No light is able to reach its bottom,
and temperatures are just
a few degrees above freezing.
Not to mention its
crushingly high water pressure.
The water pressure at the bottom
of the Mariana Trench
is over 1,000 times
the atmospheric pressure
that you're used to at sea level.
This kind of pressure
would crush anything,
even the toughest deep-sea robots
we've ever built.
But some living things managed to adapt
and thrive under such pressing conditions.
Like translucent snailfish
and sea cucumbers.
The hadal snailfish,
known as the deepest living fish,
flourishes at depths of over 8 km (5 mi).
Unlike you, deep-sea fish
don't have pockets
to store air in their bodies.
That oxygen inside your lungs
is what gives you the feeling of pressure
whenever you take a dive.
No air means this fish
has a higher tolerance
to the weight of all that water above it.
Whatever aliens were lurking down below
would also share the same characteristic.
Storing air just wouldn’t be their thing.
But what would they do for food?
Well, it's ikely they'd imitate
their seafloor neighbors once again.
Deep-sea creatures gorge
on the decaying remains of microbes,
algae or animals from above.
Our sunken ships might be
their version of a surprise buffet.
Any extraterrestrial life
down at the pit of the trench
would probably eat similar food.
They’d burrow into the biggest
carcasses they could find
and consume what's left
from the inside out,
like a giant hagfish does.
Or they might possess enormous mouths
and expandable stomachs,
allowing them to catch and digest
large quantities of food as they move.
And those big mouths of theirs
would also be filled with long fangs
pointed inward.
This would enable them
to catch and hold on to
other deep-sea creatures
or, you know,
any other prey that just so happens to dive
a little too far from the surface.
Hey, don't judge them.
In a habitat as precarious
as the Mariana Trench,
aliens would need to capitalize
on any and all sources of nutrition.
They’d also have to go the extra mile
in order to let one another know
they're out there in the pitch dark.
That’s because sunlight
can only travel up to 1 km (0.6 mi)
into the ocean.
Anywhere deeper than that
and you wouldn't be able to see a thing.
So how would our underwater aliens
put the notice out that they’re around?
Two ideas.
By sound
and by light they produce themselves.
Like fireflies, deep-sea creatures
are able to produce and emit
their own light
thanks to a process
called bioluminescence.
With it, aliens would be able
to connect with each other
through specific lighting patterns.
For long-distance communication,
they could send out sound waves
across enormous distances in the water.
Like the humpback whale,
who’s able to sing in the Caribbean
and be heard off the west coast of Ireland
6,400 km (4,000 mi) away.
Now, what would first contact
with this underwater species
look like for us?
Well, we'd have to get there first.
We’d need a vessel strong enough
to withstand the constantly
intensifying pressure.
The tiniest of cracks
would squash you and your submarine
faster than you can say “human jam”.
Once down there, we'd have to
take into account that living
at the bottom of the sea
would be like living on another planet.
If aliens existed
in the other-worldly depths
of the Mariana Trench this entire time,
they may not want to be
friendly neighbors.
And the darkness alone
would make it difficult to locate
and study our subjects.
Before approaching these extraterrestrials,
we'd have to assess
their communication style first,
slowly and patiently.
We'd need to understand how
they interact with their environment too.
That is assuming
they don’t feel threatened by our presence
and decide to do something about it.
Trust goes both ways
when you're trying not to be crushed
or eaten in the name of science.
I mean, it wouldn’t be the first time
we humans discovered a new species
and thought,
“Cool! I wonder if it tastes like chicken?”
I doubt eating an alien
would be great for your digestion.
But that’s a story for another WHAT IF.