Think that everything in a black hole gets swallowed up, never to be seen again? Well, you're half right

What happens to the information in a black hole once it disappears? Stephen Hawking thought he knew, betted on it, and lost.

Young people? Nothing but trouble. If you don’t believe the politicians, just look at physicists’ current anguish over the question of what is lost when stuff falls into a black hole. We are now in the middle of a huge crisis of confidence, just because the kids couldn’t keep their ideas to themselves.
If you think that stuff in a black hole just gets swallowed up, never to be seen again, you’re half right. The stuff is indeed gone. Yet the information about the stuff can’t be. In the 1970s, a young Stephen Hawking showed that, due to a quirk of quantum theory, black holes don’t just swallow; they also spit. A trail of particles is emitted from a black hole over its lifetime. As a result, the black hole eventually loses so much energy that it evaporates and disappears from the universe. According to Hawking’s theory, those particles contain no information of any kind, so the original information is lost once the black hole disappears.
However, a fundamental law of physics states that information can’t be destroyed. In 1997, John Preskill of the California Institute of Technology was so confident that Hawking must be wrong that the pair entered into a bet. That year, a young theorist called Juan Maldacena showed that, as stuff fell in, the information could be caught on the “event horizon”, the spherical surface of a black hole. With the information residing on the event horizon, it isn’t erased from the universe and might eventually leak back out.
Maldacena’s work was convincing enough for Hawking to concede. In 2004, he bought Preskill a baseball encyclopaedia (for reasons we won’t go into here) and the bet was considered settled.
Then, in 2010, along came the vibrant young mind of Mark Van Raamsdonk. His work has led to the new debate over the “cosmic firewall”. For information on the event horizon to leak back into the universe, there has to be a layer of ultra-high-energy particles – a firewall – just inside the event horizon. Each particle taking information from the event horizon has what Albert Einstein once termed a “spooky” link with a particle in the firewall. The link is called “entanglement” and it means that you can’t fully describe one of the particles unless you have information that resides in the other.
The problem is, the nature of Hawking’s original result shows that the particle on the outside of the event horizon also has to be entangled with another particle, one that carried away a little information from the black hole some time in the past. And a single particle can’t share that kind of entanglement with two others. So Maldacena’s idea doesn’t work. The best solution anyone can come up with involves another entanglement, this time between the particle inside the firewall and the particle that left the black hole all that time ago. That particular spooky link resolves the problem because those two entangled particles are actually one and the same.
It’s a classic Shakespearean twist. The whole problem has been a case of mistaken identity: the cosmic firewall story is the Twelfth Night of cosmology. However, most physicists don’t like this ending. Resolving all these entanglements stretches credulity too far, they say. The resolution they prefer is to acknowledge that this whole shebang exposes a gaping hole in our understanding of the universe. Maybe, they say, we need to start again.
While they scratch their heads and wonder what to do, Hawking could justifiably ask for his encyclopaedia back. If Preskill has any sense of how to play the foiled schemer, he’ll reluctantly hand it over while muttering something about those pesky kids. 
Michael Brooks’s “The Secret Anarchy of Science” is published by Profile Books (£7.99) 
In 1997 Hakwing made a bet with John Preskill of the California Institute of Technology - and lost. Photograph: Andrew Burman/Evevine/Contrasto.

Michael Brooks holds a PhD in quantum physics. He writes a weekly science column for the New Statesman, and his most recent book is At the Edge of Uncertainty: 11 Discoveries Taking Science by Surprise.

This article first appeared in the 02 September 2013 issue of the New Statesman, Syria: The west humiliated

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You are living in a Black Mirror episode and you don’t care

The Investigatory Powers Bill is likely to become law later this year, but barely anyone is resisting the dystopian surveillance it will bring.

“They’re all about the way we live now – and the way we might be living in 10 minutes’ time if we're clumsy,” explained Charlie Brooker when asked to describe the concept behind his science fiction series Black Mirror. When series three was released on Netflix last week, this sentiment was reiterated over and over. “Omg, it’s just like Instagram!!!!” squealed individuals in their masses after watching episode one, “Nosedive”, set in a world where everyone rates one another out of five after their interactions. The parallel with social media is easy, obvious, and intentional, but it doesn’t teach us much. The real ways in which our world is like a dystopian sci-fi are, in fact, much more boring.

There will be no suspenseful songs or dramatic jump cuts preluding the third reading of the Investigatory Powers Bill in the House of Lords next week. The “snoopers’ charter” is likely to become law after it passed through its House of Commons readings with a few amendments, with 444 MPs voting in favour and 69 against. In short, the Bill will give the government unprecedented surveillance powers, allowing them to intercept and collect your communications, collect a list of the websites you visit and search it without a warrant, and force your internet service provider to help them collect your data.

Even though this is highly comparable to the dark visions of the future offered by Black Mirror, no one cares. Though the Bill faced initial resistance when it was announced in 2015, it has passed through its readings relatively unscathed. Black Mirror should provide a prime opportunity to discuss issues around privacy, but people prefer to compare dystopias to things they already hate. Lord help us all if we take selfies or stare at a device which is simultaneously an encyclopaedia, a newspaper, a book, a map, a bank, a radio, a camera and a telephone for more than ten minutes.

Yet the Investigatory Powers Bill does hold many parallels to the last episode of Black Mirror series three, “Hated in the Nation”. In it, the government use autonomous drones shaped like bees to spy on its people, which are then hacked to murder hated public figures. “Ok! The government’s a c**t, we knew that already,” says DCI Karin Parke, moving on to the real issue – not that the government spies on its citizens, but that the spying device can be hacked by those naughty, naughty citizens themselves.

The hacker – Garrett Scholes – has programmed the bees to kill whoever gets the most votes on Twitter via the hashtag #DeathTo. Then, in a Jon-Ronson-worthy twist, he sets the bees on the people who used the hashtag in the first place. The actual, moral, wake-up-sheeple message of “Hated in the Nation”, then, is that we should be careful who we wish death upon on social media. But it is precisely this freedom that we should be protecting. Under the Investigatory Powers Bill, your emails and search history could be used to argue that you really want to kill Katie Hopkins, rather than were just blowing off steam.

Yet it’s hard to blame anyone for ignoring the Bill, which is off-putting not because it’s not an episode of Black Mirror, but because it is long and confusing. Breaking through the terminology is hard, even in the handy fact sheets provided, and the government can claim transparency while using alienating language and concepts.

“Some of the powers in the Bill are deeply intrusive, and with very little possible justification,” warned former MP Dr Julian Huppert last week, “the cost to all of our privacy is huge.” The good news is that you don’t have to worry about metal bees spying on you, and the bad news is that this is because the government will soon have permission to do it the easy way.


Now listen to a review of the new series of Black Mirror on the NS pop culture podcast, SRSLY:

Amelia Tait is a technology and digital culture writer at the New Statesman.