This star is about to transform
into a black hole.
And we're about to travel
inside it to see what's on the other side.
The only problem
is that we'll never be able
to report our findings back to Earth.
Because once you go inside a black hole,
there's no coming back.
So maybe there's a better way
to find out what's on the other side.
Everything that we can see
in the world around us
is based on light entering our eyes.
If an object doesn't emit or reflect light,
then our eyes can't see it.
So how are we supposed to see through
to the other side of a black hole?
It's like the darkest thing we've ever discovered.
Not only does it not emit its own light,
it also sucks up any light that comes near it.
But, according to planetary scientist
Joshua Colwell,
seeing through a black hole is not impossible.
In fact, we've already done it.
And all it took was
a little bending of space and time.
Let's take a look
at the first real image of a black hole.
Even in this low-quality picture,
you can see through to the other side
if you look close enough.
Let's enhance.
If you want to see what's going on
on the other side of a black hole,
the most crucial place to look
at is this thin ring at its center.
This is called the photon orbit.
It's a ring made up of light particles
called photons that have
orbited the black hole two, three,
or even more times before escaping.
Photons can come closer to the black hole
than ordinary matter because they're massless.
And the crazy thing is that
the photons we see in this ring
don't just come from the sides
of the black hole.
They also come from behind it.
This is because the black hole
can warp space and time to such a degree
that some of the light orbits the black hole
in a full circle.
Let me explain.
Imagine a star in space that,
from our perspective,
is obscured by a black hole.
The star sends out light in all directions.
Some of this light would
usually reach our eyes on Earth,
and some would just disappear
in other directions.
But in this case,
the light that is headed straight for us
would get sucked in by the black hole
and disappear forever.
and some of the light that
normally wouldn't have reached us
will get redirected by the black hole.
This light would become
a part of the photon orbit and eventually,
make its way to our eyes on Earth.
The light appears to come from
the gaseous rim around the black hole,
but it's coming from behind it.
Now, I know this isn't exactly
what you were hoping for
when you imagined seeing through a black hole.
You want to know what it looks like inside,
right?
Well, to do that,
we would need to travel past the event horizon,
which is essentially the edge of a black hole.
It's the point from which nothing can escape,
not matter or light.
So yeah we won't be able to report
our findings back to Earth,
but maybe we just want to see it
for ourselves anyway.
After we pass the event horizon,
we'll arrive at something called a singularity.
It can be described as a point in space
where mass has infinite density.
Everything that goes into a black hole
will end up here,
including all the light it's sucked up.
Because you'll be inside the black hole
with the light, you will be able to see it,
but its direction will be all mixed up.
You would probably just see a uniform glow
if you looked away from the singularity
and darkness if you look towards it.
And, in true "What If" fashion,
that would be the last thing you'd ever see.
So if you don't want to make that sacrifice,
but you still want to learn more
about the inside of a black hole,
then check out this week's
"What If Discussed" podcast.
We'll be talking to Professor Clifford Johnson
about transparent black holes
and new age telescopes that will allow us
to see further into space than ever before.