Stephen Hawking now thinks "there are no black holes"

The physicist, whose pioneering work on black holes in the 1970s made him a household name, has proposed a radical fudge to try and resolve a baffling paradox.

For a scientist whose career was made by his work on black holes, it might seem a little confusing to read that Stephen Hawking now thinks that they don’t exist. But that’s what “Information Preservation and Weather Forecasting for Black Holes”, the study Hawking published last week on arXiv, says: “there are no black holes”.

While this might seem surprising - after all, there’s a huge amount of (indirect) evidence that black holes exist, including a massive one several million times the mass of our Sun at the centre of the Milky Way - it’s really not. It’s Hawking’s latest attempt to solve a paradox that he, and other astrophysicists, have been grappling with for a couple of years.

So what’s he talking about? Here’s the background: black holes are objects which are so massive, with such strong gravity, that even light can’t escape. The distance from the black hole, beyond which nothing gets out, is the event horizon. However, Hawking made his name in the 1970s when he published a paper showing that black holes don’t just suck stuff up, endlessly - they spew out a beam of so-called “Hawking radiation” as they absorb other matter. That means black holes actually lose mass over time, eventually whittling away to nothing.

Black holes are frustrating, though, because their extreme gravity exposes the major inadequacy in our current scientific understanding of the universe - we don’t know how to reconcile quantum mechanics and general relativity. With general relativity, we can make accurate predictions about objects with certainty, but on the tiny scale of quantum mechanics it’s only possible to talk about the behaviour of objects in terms of probability. When we do the maths on what happens to things that fall into black holes, using relativity gives results that break quantum mechanics; the same goes vice versa.

One of the key things about quantum mechanics is that it tells us information can’t be destroyed - that is, if you measure the radiation given off by a black hole, you should be able to build up a picture of what matter fell into the hole to create it. However, if general relativity holds, and nothing can escape from inside the event horizon, then that should apply to that quantum information - any radiation that’s coming out is, Hawking showed, random. It’s the black hole “information paradox”. Either give up quantum mechanics, or accept that information can die.

Hawking was in the “information can die” camp, until 2004, when it became clear - thanks to string theory - that quantum mechanics held up (and there’s an excellent in-depth explanation of this in Nature that explores this story more fully if interested). There was just one problem - nobody could work out *how* information was getting out of black holes, even if it was happening mathematically.

And, just in case this wasn’t all entirely confusing, it turns out that our best post-2004 theory about what’s been going on gives rise to an entirely new paradox - the “firewall”.

It’s to do with quantum entanglement, where two particles are created that are identical on the quantum level. The way it works isn’t exactly clear yet - it could be something to do with string theory and wormholes - but it means that measuring the properties of one particle will give readings that mirror those found on its entangled particle. It might lead to teleportation technology, but scientists aren’t sure yet.

Joseph Polchinski from the Kavli Institute for Theoretical Physics in Santa Barbara, California published a paper in 2012 that worked out the information paradox could be solved if Hawking radiation was quantum entangled with the stuff falling in. But, due to the limitations of entanglement, if this is true, that would mean that at the event horizon a massive amount of energy was given off by particles entering and leaving.

Hence “firewall” - anything crossing the event horizon would be burnt to a crisp. And even though most scientists, including Polchinski, thought this couldn’t possibly be right - it completely contradicts a lot of the stuff underlying general relativity, for example - nobody’s yet managed to disprove it.

The choice for physicists, once again, was to: a) accept the firewall, and throw out general relativity, or b) accept that information dies in black holes, and quantum mechanics is wrong.

Still with me? Here’s where Hawking’s latest paper comes in.

(That title - “Information Preservation and Weather Forecasting for Black Holes” - might make some more sense too, hopefully.)

Hawking’s proposed solution, building on an idea first floated in 2005, is that the event horizon isn’t as defined as we’ve come to imagine it. He instead proposes something called an “apparent horizon”, which light and other stuff can escape from:

"The absence of event horizons mean that there are no black holes - in the sense of regimes from which light can't escape to infinnity. There are however apparent horizons which persist for a period of time."

Black holes should be treated more like massive galactic washing machines. Stuff falls in and starts getting tossed around, mixed up with other stuff in there, and only eventually is allowed to escape out again when ready. This happens because the quantum effects around a black hole, like weather on Earth, churn so violently and unpredictably that it’s just impossible to either predict the position of an event horizon or expect uniform effects for stuff crossing it. While the theoretical basis, that information is preserved, remains, in practice it's so difficult as to be impractical.

It’s a fudge of an idea, which tries to have its general relativity and quantum mechanics cakes, and eat them, too. Possible weaknesses, as Nature points out, are that it could imply that escaping from black holes is easier than it is in reality. It could also be the apparent horizons are just as much of a firewall as the traditional conception of an event horizon. Hawking's peers have yet to have a go at assessing his idea, so we'll have to wait to see whether the idea has merit - or whether it merely gives rise to yet more paradoxes.

Hawking in Cambridge, September 2013. (Photo: Getty)

Ian Steadman is a staff science and technology writer at the New Statesman. He is on Twitter as @iansteadman.

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Connected - to save time, money and lives

Businesses and the public sector in the UK are increasingly exploring new ways they can work with the help of connected technology – and the benefits this will bring.

We live in a world that’s increasingly connected. EE was born three years ago and has spent this time creating one of the fastest and most reliable 4G networks in any country. The effect of this growth means more for the British population as a whole, along with its critical infrastructure and emergency responders, than it does for individuals and consumers.

Why? Mobility, according to analysts CCS Insight, is “the fulcrum of digital transformation”. In the short time that mobile networks have existed – and the even shorter and more profound growth arc of 4G – mobility has moved from being about faster speeds and more services on our phones to a whole new world of possibilities for the way we live and work.

The latest mobile technologies can make small companies look big. And, the experts warn, they can make big companies look unintentionally small.

Over 500,000 businesses in the UK use our network and services to increase productivity and save money. Much of the public sector uses it to save money too – and save lives. We’d like to walk you through the stories emerging from this new world – sharing some examples of what happens when workers, customers and machines become truly connected.

Connected Vehicle

Businesses in the UK have long treated their cars, vans and other vehicles as their mobile offices, workshops or command centres, whether for field engineers, sales reps or dozens of other roles. But it’s not always been easy. 

That’s changing. Take utility Northumbrian Water. It is responsible for 55,000km of pipelines, many in rural parts of the UK. It has found a solution in the Connected Vehicle service from EE that is based on transportgrade equipment. External antennae on a van connect to a ruggedised router that deals with extreme temperatures and can handle vibrations from road surfaces. 4G becomes a shared WiFi connection for workers and devices out in the field, increasing their efficiency significantly as workers can stay connected on site, rather than having to travel back to the office.

And is it effective?

“The business case writes itself,” said Alan Sherwen, head of IS service and operations at Northumbrian Water, which is now looking at a wider rollout.

Beyond the private sector, the public sector is throwing off its image as a technology laggard. Blue-light fire, police and ambulance services are doing more than just seeing the potential.

East Midlands Ambulance Service’s head of IM&T, Steve Bowyer, describes his experience with 4G’s “reliable, consistently fast data connections” as “quite transformational”.

The ambulance service knows that every second counts, especially when accidents occur in remote locations.

Bowyer calls the use of 4G-connected vehicles “an extension of our control room” – for example, 4G-equipped ambulances allow paramedics to send vital information to hospitals ahead of arrival.

And it’s a similar story with the police. Officers collect and submit evidence from the scenes of crimes and accidents. Staffordshire Police has started to use connected vehicles and more broadly estimates its 4G devices provide the equivalent of 250,000 additional hours of policing time on the beat each year. That’s the equivalent of 100 extra officers.

Rapid Site

The technology we’re talking about – fast, robust, often rural connectivity – isn’t always about being on the move. Industries such as construction that occupy a location sometimes for a matter of months are also employing high-speed, managed services to serve those on site.

Jackson Civil Engineering used to have to wait three months to get a line installed. It was holding back the business.

“The challenges I face are making sure the guys on site get connectivity and transmit information from laptops, mobile phones and tablets,” said Justin Corneby, the company’s IT manager. “If there’s no connectivity for our guys on the ground it almost stops them working completely.” Now setup at a new location takes under three days, and speeds tend to be up to 60Mbps where, before, a fixed line gave the company 8Mbps.

Housing association Green Square faces a similar challenge in its efforts to supply about 400 homes every year in the west of England.

Mark Gingell, ICT service manager at Green Square, said: “[We have] some challenges about how do we get our staff access to the internet. What we want is a seamless process for them to be able to log on and have the information at hand. The ultimate goal is to make great places where people can live.”

Public WiFi – in a box

Other types of business are on this connected journey too. Richardson’s operates 310 holiday boats on the Norfolk Broads and 4G Public WiFi from EE means not only coverage and simplicity for customers wanting internet access but knowing that compliance and online safety for families, through web filtering, is taken care of. In fact a whole range of businesses are now possible, many employing mobile payments systems which through their security and 4G connections open up a world of pop-up possibilities to businesses big and small.

Connected Health 

And lastly, the NHS is showing us that innovation can be built on even relatively simple technology. ‘Did not attend’ – or DNAs – cost the health service around £900m every year. That breaks down as £137 for every missed hospital appointment, £45 for each at a GP’s surgery. 

Intelligent messaging from EE means patients get a text message and simply reply to cancel or confirm an appointment. DNAs have been reduced by 67 per cent in one case, freeing up slots for others. That means there is the potential to save the NHS over £500m annually, just by improving the booking and scheduling service for patients with intelligent messaging. Meanwhile healthcare professionals get to target groups by demographics – for example, elderly people when it’s flu jab season. In short, this approach saves time, saves money and even saves lives.

Now you can

When we were the first to launch 4G in the UK, we had a simple message: Now you can. Most people took that to mean simply that smartphones, tablets, laptops and upcoming smart devices could get a faster network connection. But it’s been about much more than that.

Today, being connected in this way is a vital component for business and Britain’s vital public services. Our recent research of 1,000 UK businesses shows that 50 per cent of customers say 4G is critical to their business success. They report a 10 per cent uptick in productivity when adopting 4G – and gains can be greater in the public sector.

And we’re nowhere near finished. Now any organisation in the private or public sector can share in this connected story, employing new technology and innovative approaches as a managed service or in any way that best works for them. We are just as excited about the next three years as the last three.