Something strange is happening
on the outskirts of our Solar System.
It could be a large, mysterious planet.
Or it could be a black hole.
Far beyond Neptune, there are small,
icy objects orbiting our Sun.
These are trans-Neptunian objects,
or TNOs.
And these TNOs
have an oddly clustered orbit pattern.
This type of orbit
doesn't happen on its own.
Something is making those objects
orbit like that.
And whatever that something is,
it would need to be at least 17 times
more massive than the Earth
and 10 times further from the Sun
than Neptune is.
Could it be the mysterious Planet Nine?
So far, there is no evidence
to back up the theory
of a massive ninth planet
disrupting the orbits of these objects.
But scientists
have another possible explanation.
One that could
spell trouble for humanity.
What if Planet Nine
isn't a planet at all,
but a planet-sized black hole?
If you try to picture
a planet-sized black hole,
you might imagine a massive void
hat is devouring everything in its path.
But a black hole
of this size would be small.
That’s because this black hole
would be the mass of a planet.
All that mass
would be packed into an extremely dense
amount of space,
no bigger than a grapefruit.
Well, you've seen enough WHAT IF
at this point to know that black holes
come in bigger sizes too.
Stellar black holes get,
10 to 24 times the mass of our Sun.
They're pretty common.
Astronomers estimate
that there may be anywhere between
10 million to one billion
in the Milky Way Galaxy alone.
If our own Sun
transformed into a black hole,
it would only be about
5.8 km (3.6 mi) wide.
This scenario
could cause one or two significant
problems for life on Earth.
But let's go back to our tiny black hole
hiding at the edge of the Solar System.
It might be small,
but it would have enough mass
to disrupt the orbits
of the Trans-Neptunian Objects.
But with a black hole
that far away from Earth
and in a fixed orbit around the Sun,
you wouldn't see much
of a difference in your day-to-day.
But where's the fun in that?
In the best traditions
of our mind-blowing scenarios,
let's destabilize
the black hole's orbit,
just a little.
The extreme nature of black holes
manifests itself only when an object
is close to the event horizon.
This is the threshold around a black hole,
where an object would need to travel
faster than the speed of light
to escape the gravitational pull.
You might know it as a point of no return.
For this particular black hole
to become dangerous for Earth,
its gravitational pull
would need to be much stronger.
This tiny black hole
would need to be able
to pull in entire planets.
Combine the great pull
with a bit of a disrupted orbit,
and you've got an invisible gravitational monster
swallowing our planetary neighbors
one by one.
As planets and asteroids
from our Solar System
reached the event horizon,
they would be torn apart
into small subatomic components
and compressed to a single point.
From Earth, we'd see Neptune,
Uranus, Saturn and Jupiter
disappear into nothingness.
Then, Mars would be gone too.
Earth would be next.
As the black hole approached,
Earth would begin to bulge.
This would cause massive earthquakes,
volcanic eruptions
and tsunamis all over the planet.
If you somehow survived up to this point,
the end would be near.
As our planet got closer to the black hole,
it and everything on it
would be pulled apart and stretched out.
This is a process known as spaghettification.
Chances are you’d die long before
you could get anywhere close
to the event horizon.
Eventually, the Earth would be sucked
into a this tiny gravitational monster
until there was nothing left.
Well, maybe a trail of debris
would serve as a reminder
that Earth had existed at all.
But this wouldn't happen in an instant.
In 2013, scientists observed a planet
about 14 to 30 times as massive as Jupiter
being swallowed by a black hole.
The whole process,
from initial disturbance
to total destruction,
took two to three months.
But when it comes to this distant object,
its stable orbit of the Sun
for billions of years is a good sign
that there isn’t much cause for concern.
When we start to see changes
in other planets,
moons and asteroids,
then something dangerous
might be going on.
And maybe Planet Nine
is just another planet in the Solar System.
But that's a story for another WHAT IF.