What do you think would happen if a black
hole swallowed the Earth?
Your house is gone.
Your puppy's gone.
Your mom's lasagna recipe--just gone, behind
the horizon of the black hole.
If that weren't bad enough, then radiation
leaves the event horizon of the black hole,
stealing the black hole's mass and shrinking
it until--poof--it's gone.
So, what about humanity's legacy?
It's one thing to say that it's just trapped
behind the event horizon of the black hole.
But it's another thing to suppose that the
world is gone altogether, scrambled up in
random particles that are leaving the event
horizon of the black hole.
So here's the question: Is it truly gone forever?
From the evaporated remains of the black hole,
could you ever really reconstruct the knowledge
of humanity?
This is essentially the 40-year-old unsolved
puzzle called the black hole information paradox.
Here are the three leading answers.
Unfortunately, every single one of them breaks
physics as we know it.
So, humanity's legacy--and your mom's lasagna
recipe--are trapped behind the black hole's
event horizon.
And for them to escape the intense pull of
the black hole, they would actually have to
travel faster than the speed of light.
In normal, everyday life, that can't happen;
that's an Einstein no-no.
Because if you could somehow surpass the speed
of light, then your clock would actually start
moving backwards and you could go back in
time...possibly changing the past.
But maybe the physics in a black hole is special.
If things could travel faster than the speed
of light in there, then maybe information
could escape somehow.
What if the Earth never actually fell into
the black hole?
What if there's some wall at the event horizon,
and when the Earth hits the black hole, all
its information goes splat onto that wall?
And when the black hole evaporates from that
event horizon, the Earth's information is
on the outside.
It's right there to evaporate with those particles
that are leaving.
So the problem here is that in relativity,
a black hole is nothing but a point in space,
just a massive dot, surrounded by empty space.
It's warped space, but empty space.
So, having this random wall that soaks up
information--well, that goes against everything
we'd predict in relativity.
Okay, so what if all the information from
humanity is simply, just gone?
Here's the problem with information loss:
When you send information in a phone call
or a text or an email, what are you sending?
You're sending energy.
Energy and information are tied to each other.
Losing information actually means losing energy.
And if there's one rule that holds the universe
together, it's conservation of energy.
If you get rid of that, then things could
just disappear without warning.
So, what would actually happen to our legacy
if a black hole ate the Earth?
Physicists are using the Event Horizon Telescope
to look at the event horizon of the supermassive
black hole at the center of our galaxy.
Observations of gravitational lensing of light
around the event horizon could tell us whether
we have to accept backwards time travel, information
loss, random walls that just steal information,
or something completely new.
In the meantime, what do you think?
If the Earth were swallowed by a black hole,
would the information of humanity be lost
forever?
Or could you get that lasagna recipe back?
Also, you can learn much, much more about
black holes in NOVA's two-hour special, "Black
Hole Apocalypse."
The link is in the description.
