Imagine you're floating in space.
It's quiet and cold, serene and slightly terrifying.
Suddenly you feel a tug. It's faint at
first, but it gets stronger, pulling you
towards an empty region of the sky.
Before you know it, you've fallen into a black hole.
Could you survive? Maybe, but it's going to get a bit weird.
Black holes are objects so massive and
dense that not even beams of light,
the fastest things in the universe, can
escape their gravitational pull.
Essentially, any objects sufficiently
compressed can form a black hole.
So if an evil alien empire decided to
squash Earth down, it would form a black hole
about the size of a peanut.
Making a black hole is hard work.
The existence of black holes was
predicted by Einstein's theory of
general relativity, which states that
matter warps space and time creating
what we call gravity.
The theory also predicts that when two
black holes collide, they send out
ripples through the fabric of space-time
called gravitational waves. These ripples
were first detected in 2015
by an incredibly sensitive experiment
called LIGO, proving Einstein right.
Then in 2019, we managed to photograph a
black hole for the first time.
On the picture we can see a bright ring
of material circling the black hole
itself, which is silhouetted in the center.
Pretty amazing huh? And there's even more
exciting research going on all the time.
In New Scientist you can read loads
more amazing stories from the world of physics.
Subscribe now and save 20% by hitting the
link on the screen and using the code SAM20.
If you are unfortunate enough to get
sucked into a black hole it would be
devastating but also pretty spectacular.
As you circle the drain of this cosmic
plughole, all the photons being pulled
alongside you would create a stream of
blinding light and the stars would begin
to distort and bend.
Then a looming darkness would wash over
you, any further and you'll cross the event horizon,
the line where the gravity of the black
hole is too strong to resist.
You wouldn't just be crushed but your
body would be pulled apart at different speeds
resulting in, what physicists delightfully call, spaghettification.
Once you're inside the black hole it
gets a bit harder to work out what happens.
General relativity's equations fail
catastrophically at the center of the black hole
called the singularity. This is where
quantum theory comes into play.
But quantum theory and general
relativity don't really get along.
General relativity says when matter falls
into a black hole information is
destroyed but quantum mechanics says
that can't happen.
We need a unified theory to reconcile the two.
One way to do that is with string theory
which says that matter isn't composed of
fundamental particles after all,
it's actually made of tiny strings.
If that's the case
then black holes aren't really black
holes at all, they're just fuzzy balls of
tangled string.
You'd still die a pretty terrible death
if you fell into one of these fuzzballs
but instead of becoming part of nothing,
you would become part of this tangled
ball of string.
Still that's not much of a consolation.
Is there a way you could survive?
Well, sort of. Black holes come in a range
of sizes,
from as small as a single atom to a
million times the mass of the sun or more.
If you have a choice, your best bet is to
fall into a larger one.
Although the gravity is bigger, the
stretching tidal force is less, meaning
you might just live to tell the tale.
Unfortunately, you wouldn't be able to
escape and tell anyone what you'd seen.
Or could you? There is one possible way
you could make it out again through a
hypothetical object called a white hole.
Just as black holes don't allow anything
to escape, white holes can't keep
anything together.
One idea is that every black hole is
connected to a white one through an
interdimensional tunnel called a wormhole.
Fall into one and you'll eventually get
thrown out the other end where spacetime
bounces back out,
vomiting you up with it. Alternatively,
you could wait for a black hole to turn
into a white one.
To an outside observer this would take
billions of years, but inside, thanks to
the strong gravitational pull,
time would be speeded up, taking you mere milliseconds.
So maybe there is a way you can fall
into a black hole and survive,
but I don't fancy the risk myself.
Spaghettification just doesn't sound
very nice.
What about you? Tell us in the comments
and don't forget to like and subscribe
for more Science with Sam.
