Black Hole Information Paradox – Breakthrough Junior Challenge 2017 Europe Regional Champion

Black Hole Information Paradox – Breakthrough Junior Challenge 2017 Europe Regional Champion


You’ve read about Black Holes on the Internet. Came across the unsolvable Information Paradox
that Physicists are still puzzled about after 40 years! Intrigued and now trying to decode Hawking’s
new paper on BMS Supertranslations. Stop! You’re getting way too ahead of yourself,
let’s go back to the drawing board. First off, what really is Information? In the Quantum world, it’s about a particular
description of the states of particles whether that be their spin, momentum, mass or any
other measurable parameter and the probabilities of their interactions with each other. Quantum Physics tells us that information
must be preserved throughout the Universe. That is, if I tossed my cookie in a fire,
it is still retrievable even after it’s been destroyed. The burning of my cookie generated a very
particular arrangement of ashes, heat and light, so in principle, if we could reverse
time, it is possible to reconstruct my cookie atom by atom. This Universal rule must also work if I threw
it into a Black Hole instead, right? Yes, if it were a classical one. A classical black hole is a region of space-time
where its gravitational pull is so strong that not even light can escape after crossing
the point of no return – The Event Horizon. From an outside we can only measure three
properties, which are how heavy it is, its electrical charge and its rotational energy. There is no way to tell whether it was formed
through the collapse of a star that is 30 times the mass of our Sun, or if I had somehow
compressed the entire Earth down to the size of a peanut. All the information about its formation and
my cookie is trapped inside the black hole, in theory, it’s still there, just
hidden behind the horizon. This information now the black hole’s entropy
and is proportional to the area of the event horizon. Voila! information is preserved and there
is no violation of the laws of physics. But in the 70’s when incorporating Quantum
Mechanics into the big picture, it was discovered that black holes emit randomised thermal radiation
which carries away mass, leading to complete evaporation. If a black hole evaporates into nothingness,
we would physically see the area of the event horizon get smaller, until it disappears. Hold on,we just said that entropy is equivalent
to the area of its event horizon. So…Where did all that hidden information
go? Just like I am able to retrieve my cookie
after I threw it in the fire, this information should also be preserved after it falls into
a Black Hole. We now know that Black Holes probably don’t
lose information, due to the Holographic Principle, stating that information is somehow encoded
onto the event horizon in 2-dimensional form, like pixels on your computer screen, which
could potentially affect how the Hawking radiation escapes. There’s an amazing thing about paradoxes like
this: When we figure out the solution, we’ll have discovered something truly fundamental
about the laws that govern our physical reality.