Stephen Hawking Misled us on Hawking Radiation

Here's the Reality...Hawking Radiation: The Oversimplified Picture vs. The Reality...Hawking radiation suggested that black holes are not completely black, but in fact, emit faint radiation, and decay over time. But Hawkings lied about how it works in his own book. In this video, I show you how Hawking Radiation actually works.

The basic idea is that empty space is not actually empty. Instead, it's teeming with a sea of virtual particles. These are fluctuations in the quantum fields, where particles and antiparticles spontaneously appear and disappear, annihilating each other constantly. This happens everywhere in spacetime. You can’t see it because these are virtual particles that appear and disappear so quickly that they are not measurable.

Hawking explained, in his popular 1988 book, “A brief history of time” that when a pair of virtual particles forms at the very edge or the event horizon of a black hole, before they can annihilate each other, one of them falls into the black hole while the other escapes. The one that falls into the black hole, carries negative energy, decreasing the mass of the black hole a tiny amount. The one that escapes carries away positive energy, and that’s the Hawking radiation that we observe. This description is incorrect. It is not the explanation in his 1974 paper.

Virtual particles are formed due to the Heisenberg Uncertainty principle, formulated by Werner Heisenberg in 1927. One way to express this principle is in terms of energy and time. The uncertainty in energy times the uncertainty in time has to be greater than or equal to a constant, which is Planck’s constant, h, divided four pi. All measurable real particles obey this uncertainty. But what this also means is that unmeasurable virtual particles can exist below this inequality. In other words, a particle with a low enough energy that exist for a small enough time can exist as long as the product of their uncertainties is LESS than h over 4 pi.

To any observer located anywhere in the Universe, the zero point energy will appear to have the same value no matter where they are located. But, relativity tells us that different observers perceive different realities. The clock of an observer in a gravitational well due to curvature of spacetime, will tick more slowly compared to an observer standing far away in flat spacetime.

If we look at this uncertainty equation in the context of an observer standing near the highly curved gravity well near a black hole’s event horizon vs an observer standing infinitely far away in flat spacetime. The flow of time will be different for them. To the local observer near the black hole, he will not be able to detect any particles because they will all be virtual. But for someone observing the black hole from far away. He will detect those same virtual particles as real particles because the product of time and energy will be different for him.

So the bottom line is that the observer far from the black hole, who is unaffected by the extreme curvature of spacetime near the event horizon, will interpret the quantum field as being filled with real particles, which we observe as Hawking radiation.

And this is what Hawking also described in his original paper.As the black hole emits Hawking radiation, it loses energy (or mass) over time. 

The simplified incorrect picture that Hawking presented in his book has led to some common misconceptions. For example, his description made people believe that the radiation is created at the event horizon. In reality it is mostly created relatively far away, around 10-20 times the radius of the event horizon. This makes sense when we stop thinking about Hawking radiation happening due to the event horizon, but rather due to the extreme curvature near the black hole itself. Also, the radiation would occur not only in black holes but also from other very dense objects with high spacetime curvature such as white dwarfs and neutron stars.

00:00 - Hawking's misleading explanation

01:25 - Empty space is not empty

03:20 - How virtual particles arise

05:18 - How Relativity plays a role in Hawking Radiation

06:40 - How Hawking radiation really arises

08:47 - What is the temperature of Hawking radiation

09:50 - Misunderstandings of Hawking radiation