The world lost one of its finest minds earlier this year. Professor Stephen Hawking, one of the leading minds in physics and a major forces in learning how the universe around us really works – passed away in March this year, leaving behind him an incredible legacy, not least his revolutionary work A Brief History of Time. Hawking’s legacy is enormous – perhaps even immeasurable – and moments such as the scientist inviting time travellers to his funeral remain idiosyncratically newsworthy. This week, it has been revealed that Hawking’s final study – as part of a scientific paper released by his Cambridge and Harvard colleagues – revolves around black holes, which the physicist famously theorized about in a number of papers and books previously.
Hawking’s final paper surrounds the concept of the information paradox, which revolves around concerns over what happens to information as a result of items falling into black holes. It all tails back to Albert Einstein, who made predictions about black holes back in 1915 as part of his general relativity thesis – and Hawking built upon this himself in his lifetime, by suggesting that such holes would possess a temperature as well as the ability to spin, its own mass and its ability to charge.
Hawking’s theory with regard to black hole temperature became a life-long concern for the scientist, whose final paper discusses whether or not objects are truly lost when they fall into these holes. If black holes eventually evaporate, what happens to everything that has been consumed by them? Hawking’s paper – Black Hole Entropy and Soft Hair – was co-authored with Professor Malcolm Perry, who discusses whether or not information can ever be retrieved once it has travelled into the mouth of a black hole. “The difficulty is that if you throw something into a black hole, it looks like it disappears,” Prof. Perry observes.
“What this paper does is show that ‘soft hair’ can account for the entropy – it’s telling you that soft hair really is doing the right stuff,” Perry continues, as his paper observes that the entropy of a hole can be recorded by photons around a hole’s event horizon. Perry and Hawking refer to this phenomenon as ‘soft hair’ – which they believe may be the key to information being preserved as it enters into a black hole.
It’s fascinating research – though Perry believes there’s plenty more analysis where that came from. “We don’t know that Hawking entropy accounts for everything you could possibly throw at a black hole, so this is really a step along the way. We think it’s a pretty good step, but there is a lot more work to be done.”