Media, Entertainment and Sport

Stephen Hawking’s final theory on black holes has been published, and you can read it for free

This artist’s concept released October 30, 2017 shows a black hole with an accretion disk - a flat structure of material orbiting the black hole - and a jet of hot gas, called plasma. NASA/JPL-Caltech/Handout via REUTERS   ATTENTION EDITORS - THIS IMAGE WAS PROVIDED BY A THIRD PARTY - RC1808FDC440

The new research explains how at least some information could be preserved once a black hole disappears Image: REUTERS

Johnny Wood
Writer, Forum Agenda
Our Impact
What's the World Economic Forum doing to accelerate action on Media, Entertainment and Sport?
The Big Picture
Explore and monitor how Media, Entertainment and Sport is affecting economies, industries and global issues
A hand holding a looking glass by a lake
Crowdsource Innovation
Get involved with our crowdsourced digital platform to deliver impact at scale
Stay up to date:

Media, Entertainment and Sport

Professor Stephen Hawking dedicated much of his career to unravelling the mysteries of black holes, and now the final chapter of his research on the “information paradox” is online.

Days before his death in March, aged 76, the renowned physicist and cosmologist completed work with colleagues at Cambridge and Harvard universities on a theory of what happens to the information in objects that fall into black holes.

Malcolm Perry, a professor of theoretical physics at the University of Cambridge and a co-author on the paper, Black Hole Entropy and Soft Hair, said in the Guardian that the information paradox was “at the centre of Hawking’s life” for more than 40 years.

 Stephen Hawking’s inspirational work explaining the mysteries of the universe lives on.
Image: REUTERS/Lucas Jackson

The ‘information paradox’

Building on the foundations laid by Albert Einstein in his groundbreaking theory of relativity, Hawking used quantum theory to contend that in the cold depths of space black holes emit heat and slowly contract until they no longer exist.

Hawking’s theory suggested that the information in objects entering a black hole would disappear and be lost forever. This contradicted a basic law of quantum mechanics, which demands that information relating to an object is never lost, and gave rise to “the information paradox”.

The new research explains how at least some information could be preserved once a black hole disappears. As an object enters a black hole, the temperature increases and raises the entropy level – a measure of an object’s internal disorder.

A sheen of photons surrounding a black hole’s event horizon – the point at which light cannot escape the extreme gravitational pull – may record the hole’s entropy. The research centres on how the protons, known as “soft hair”, store information associated with entropy.

The paper represents a step towards solving the information paradox, but there is still work to be done. Physicists must now determine how information associated with entropy is stored in soft hair and how the information escapes a black hole when it evaporates.

“Understanding the microscopic origin of this entropy – what are the underlying quantum states that the entropy counts? – has been one of the great challenges of the last 40 years,” Marika Taylor, professor of theoretical physics at Southampton University in the UK, who studied under Hawking, told the Guardian.

Have you read?

“This paper proposes a way to understand entropy for astrophysical black holes based on symmetries of the event horizon. The authors have to make several non-trivial assumptions so the next steps will be to show that these assumptions are valid.”

Shedding light on the universe

Hawking found fame with the release of his 1988 bestseller A Brief History of Time, which made complex topics such as the big bang and black holes accessible. However, long before he caught the attention of the public, he had been celebrated by the scientific community for his contributions to their understanding of the universe.

Aged 21, he was diagnosed with motor neurone disease, or amyotrophic lateral sclerosis (ALS), and given just two years to live. He confounded the prognosis, with a life and career spanning many decades, although the degenerative condition severely impacted his life.

Following undergraduate studies at the University of Oxford, the young scientist moved to Cambridge where he lived until his death on 14 March 2018.

Early in his career, an ambitious Hawking set himself extraordinarily high standards, declaring: “My goal is simple. It is a complete understanding of the universe, why it is as it is and why it exists at all.”

Don't miss any update on this topic

Create a free account and access your personalized content collection with our latest publications and analyses.

Sign up for free

License and Republishing

World Economic Forum articles may be republished in accordance with the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Public License, and in accordance with our Terms of Use.

The views expressed in this article are those of the author alone and not the World Economic Forum.

World Economic Forum logo
Global Agenda

The Agenda Weekly

A weekly update of the most important issues driving the global agenda

Subscribe today

You can unsubscribe at any time using the link in our emails. For more details, review our privacy policy.

Social media in the crossfire: This is how you establish 'digital trust'

Kate Whiting

February 20, 2024

About Us



Partners & Members

  • Join Us

Language Editions

Privacy Policy & Terms of Service

© 2024 World Economic Forum