Deep under the Earth’s surface,
there’s a scorching hot ball of metal.
And scientists just discovered
that something very wrong
is happening to it.
If you were to dig straight down
into our planet,
you’d shovel through
four distinct layers
on your way to the center.
First, there’s the rocky crust,
and that’s followed by the hot
liquid mantle.
2,900 km (1,800 mi) later,
you’d reach Earth’s outer core,
made up of liquid iron and nickel.
Combined with the solid
iron inner core,
the two core layers of our planet
are about the size of Mars.
But unlike the red planet,
they’re scorching hot.
At 10,000 °C (18,032 °F),
they’re hotter
than the surface of the Sun.
And there’s
also a lot of movement down there.
The motion of molten metal
in the outer core
is what’s responsible
for generating Earth’s magnetic field.
Without that,
we wouldn’t be able to hold
onto our atmosphere
and we’d lose our protection
from dangerous space radiation.
And the inner core
of our planet is moving too.
But new research suggests
that it’s slowing down
to rotate more in sync
with the rest of the planet.
But slowing down
isn't dramatic enough.
Let's see what happens
when both layers of the core
stop moving completely.
If only the hot, solid
inner core inside
the outer core
stopped moving, well,
you wouldn’t
need to worry about the apocalypse
just yet.
The slowing down of the inner core
would mostly impact
the speed at which Earth spins.
It could slow our rotation
down enough that
our days would become longer.
And over time,
this could degrade
our magnetic field.
Yeah, that would be bad news.
But not nearly as bad
as what would happen
if the syrupy outer
core stopped spinning too.
Without that layer’s rotation,
well, you’d have to kiss
our magnetic field goodbye.
And this would put Earth
on a course to end up looking
a lot like Mars.
4.2 billion years ago,
Mars could have been warm enough
to have oceans
where life might have thrived.
But when the red planet’s
core froze in place,
its once-strong magnetic field weakened.
As the Martian magnetic field degraded,
its atmosphere
was chipped away
by ferocious solar winds
slamming into the planet
at speeds of several hundred km/s.
That’s when the planet transformed
into the dry,
lifeless desert you know today.
But back to Earth.
Before it completely
turned into a desert planet, well,
things would get a little shaky.
If the core was to suddenly
stop rotating,
the tectonic plates
would violently slam into each other.
It would be a lot
like when your bus driver hits
the brakes hard
and you go flying into the other
bus riders.
This sudden collision
of tectonic plates would cause
massive earthquakes
along the plate boundaries
all around the world.
These quakes would destroy
buildings, roads and bridges.
Electricity, phone lines
and water systems
would be severed.
Ultimately, millions of lives
would be lost
and millions more
people would be displaced.
Now, as devastating as these
earthquakes would be,
the damage
would just be getting started.
With the disappearance
of our magnetic field,
you’d be exposed to dangerous
cosmic radiation
that would bombard
the surface of our planet.
These high-energy
particles from the Sun
would interact
with the abundance
of nitrogen and oxygen
in our atmosphere.
And this would destroy
our protective ozone layer,
allowing more
UV radiation to reach the surface.
Combining these solar rays
and UV radiation
would be enormously harmful
to all life on Earth.
It would damage your DNA,
leading to mutations
and cancer.
And the halting of the core
would also make navigating
the globe more difficult.
Yeah, I hope you have a good trail map
for your next camping trip
because compasses
would be totally useless.
All kinds of migratory animals
would lose their way too.
Birds flying south would get lost
and freeze to death,
while sea turtles
would never find their way back
to the beaches
that they lay their eggs on.
The earthquakes caused by the core
suddenly stopping
would have already done
significant damage
to the power infrastructure
around the world.
But the lack of a magnetic field
would continue disrupting things
even more.
The solar radiation
bombarding the surface
would damage
all kinds
of electronic devices,
and would threaten
our power grids.
You would end up
losing power more often.
Maybe even permanently.
But in reality,
you don’t have to worry
about a catastrophe like this.
This study, which implied that
the core has stopped
and we’re all doomed,
was a little overhyped.
Scientists didn’t
even talk about the outer core.
No, they just meant the inner core,
which rotates independently
from the rest of the planet.
It doesn’t stop or reverse
its rotation.
It just moves slower and faster,
like it’s done
for the billions of years
of our planet’s existence.
Well, good news everyone,
we’re safe
on our big, blue space rock.
At least the planet
is still spinning.
Just imagine what would happen
if Earth’s rotation
suddenly stopped.
Well, that’s a story for another WHAT IF.