Detailed Report on Black Holes and Hawking Radiation Theory

This report delves into the intriguing relationship between black holes and Hawking radiation, a theory proposed by Stephen Hawking that combines general relativity and quantum mechanics. It explains how black holes, contrary to initial beliefs, are not entirely black but emit energy known as Hawking radiation. The report traces the development of this theory, starting with Einstein's theory of relativity and the concept of black holes forming from the collapse of massive stars. It further discusses the role of quantum mechanics in understanding the vacuum energy and particle-antiparticle pair production near the event horizon of a black hole, leading to the emission of Hawking radiation. The process describes how black holes slowly evaporate over billions of years, culminating in a final explosion. The report also highlights the significance of Hawking radiation as a step towards unifying general relativity and quantum mechanics into a "Theory of Everything."

Running head: BLACK HOLES AND HAWKING RADIATION
BLACK HOLES AND HAWKING RADIATION
[Author Name(s), First M. Last, Omit Titles and Degrees]
[Institutional Affiliation(s)]

2
BLACK HOLES AND HAWKING RADIATION
Hawking Radiation: Black Hole and its
Fate
While the whole scientific world thought that black holes would stay forever, a talented young
man from England invented a theory in 1974. The theory was dubbed Black Hole Explosion and
was a combination of both Relativity and Quantum Mechanics. The theory of Black Hole
Explosion stated that black holes are not as black as we think but they radiate energy known as
Hawking Radiation.
Hawking presented his idea in 1970 and he was not sure about the method to measure the
entropy of black hole but a young student from Preston University named Jacob Bekenstein
suggested that if the black hole has entropy, the surface area of the black hole which is known as
the event horizon will be the measure of its entropy and if any matter enters the black hole the
size of the event horizon will increase (Blundell, 2015).
Stephen Hawking was one of the brightest and most innovative minds of his time. His limitless
creativity has made tremendous contributions to a plethora of remarkable discoveries that
deserve every ounce of praise despite his body being paralyzed by Amyotrophic Lateral
Sclerosis. His life was an ongoing journey in which he solved many mysteries of the universe.
One of such mysteries was about the strangest objects in the space known as black holes. He did
not do the actual discovery of the black holes but rather was the one who described their
influence on the environment using mathematical approaches (Blundell, 2015).

3
BLACK HOLES AND HAWKING RADIATION
“One of the principal contributions of Hawking to modern physics is taking black hole into
mathematical terms and expressing its influences on the environment,” said Paul Delaney,
Director of the York University Astronomical Observatory and Senior Lecturer, Astronomy and
Space Exploration.
"To understand the concept of Hawking Radiation, we need to understand the stars, black holes
and how Hawking Radiation works in conjunction with some of the most known theories," he
said.
It all goes back to 1915 when Einstein came up with the theory of Relativity, one of the greatest
discoveries ever made in the field of physics. He discovered that gravity is a factor of the space
and massive objects like the star cause distortion in the space (Susskind, 2014). The distortion
caused makes the space around them curve hence bringing about an effect on the motion of the
bodies which are close to them.
A simple example is the sun that is so massive that it makes up to 99.86 percent of the total mass
of our solar systems and the distortion caused by this mass in the space is the reason that all the
planets and the countless asteroids revolve around it (Ong, 2015).
The theory of relativity brought one more idea along with it, the idea that if a star is as heavy as a
mass of ten suns or more, it can collapse under the pull of its own gravity to form a black hole.
“The black hole is formed when the star dies in a supernova explosion under the influence of its
own gravity,” said Professor Delaney.
My story will show that black holes are not as black as we think but they radiate energy known
as Hawking Radiation as will be explained in details in the later stages of this discussion.

4
BLACK HOLES AND HAWKING RADIATION
He farther explains that stars are basically nuclear furnaces composed of hydrogen gas and fuses
two hydrogen atoms into one helium atom and produces a tremendous amount of energy. This
nuclear reaction takes place inside the core and the resulting energy floes out from the core. The
life of the star is determined by the constant struggle between the gravitational pull of its core
and the energy released by the nuclear fusion at its core (Ngampitipan, 2014).
The gravitational force of the black holes is very huge such that they distort the space in such a
way that the escape velocity from their gravitational pull exceeds the speed of light. This means
that not even light can escape it once it goes beyond the event horizon known as the point of no
return.
Most of the scientists believed that objects like this can’t exist in nature for quite a long time
after this prediction (Hawking, 2016). They as well believed that another occurrence will prevent
it from happening but it was, later on, proved over the years by the combined work of Karl
Schwarzschild, John Wheeler besides numerous other astrophysicists that black holes do exist
but still it was a topic of debate. Black holes were still united mysteriously and most of the
scientists still trying to unfold the mystery.
Hawking developed his interest in the theory of relativity and black holes when he started his
Ph.D. at the University of Cambridge despite being diagnosed with ALS, his determination
superseded the disease (Bailyn, 2014).
During his research on black holes, he noticed that the size of black holes can only increase or
remain at the same size but cannot decrease in size since it is obvious that black holes swallow
all any object that comes too close to them. If they swallow more materials or matter, their mass
and entropy increases.

5
BLACK HOLES AND HAWKING RADIATION
The search was similar to the second law of thermodynamics which starts that the entropy of an
isolated system can never decrease but instead will stay either constant or increase. Entropy is
defined as the amount of disorganization of something or the degree of disorder in any system.
The entropy of things tends to be lower if they are nicely packed together and increase when the
things are loosely packed (Xavier, 2014).
Jacob Bekenstein also raised one question as he said that according to second law of
thermodynamics, if the black hole has an entropy, it must also have a temperature and it has a
temperature then it must radiate the heat to the environment, but if nothing can escape from the
black hole then how will heat be radiated and if it does not radiate, t violates the second law of
thermodynamics.
This statement from a young student was a challenge to the idea of Hawking and in the efforts to
prove him wrong, Hawking started searching for entropy. He even embraces the advice from
other scientists but every one of them stated that if a black hole has entropy it must radiate
energy.
Hawking realized there is another concept in physic called quantum mechanics which tells about
the working principles of vacuum (Susskind, 2014). According to quantum physics, space is
never empty, particles are being regularly created and destroyed in the vacuum and the particles
do this on the basis of Heisenberg’s uncertainty principle.
The empty space is not really empty but it contained virtual particles known as matter and
antimatter. These pair of particles came into existence for a very small during of time and
annihilates each other very quickly (Blundell, 2015).

6
BLACK HOLES AND HAWKING RADIATION
Hawking realized that if the same phenomenon occurs near the event horizon, it is possible that
one of the virtual particles will fall into the black hole and the others will escape becoming a real
particle and therefore black hole will lose its energy.
Delaney further explained that these particles which form simultaneously in the vacuum can be
assumed as electrons and photons. If they make contact with each other they disappear giving
away little energy but near the event horizon of a black hole one of the particles zips off into
space and the other gets drawn inside the black hole. The particle that zips away to the universe
carries away a little energy (Ngampitipan, 2014).
“In the process a black hole is actually sort of radiating away a little bit of energy in this pair
production process, meaning that it is quietly and steadily evaporating but it takes billions of year
for a black hole to completely disappear,” Professor Delaney said.
While starting, this process occurs extremely slowly but as a black hole gets smaller and smaller,
the process starts to gain the speed because the temperature of smaller holes is much high than
that of massive black holes and if the temperature is high its radiation emission is also high
(Calmet, 2013).
“it is believed that when a black hole becomes very small and enters the last stage of its life, it
dies with a huge explosion which radiates the energy equal to the billions of nuclear bombs and
this marks the death of a black hole,” said Professor Peet.
This theory was of importance from the point of view of fundamental physics because for the
first time the idea of Quantum Mechanics was joined with the Theory of General Relativity and
it is one of the greatest unsolved problems in physics that helps to bring the theory of gravity into

7
BLACK HOLES AND HAWKING RADIATION
an overall understanding of Quantum Mechanics and it was one of the steps toward the “Theory
of Everything”.
“I think that 20th century had two principal scientists, Stephen Hawking and Einstein," said
Professor Delaney. "The two of them were able to make a great deal of sense of the universe
which is quite confusing for most of us. They were able to check observation, theories and marry
them together in ways that few scientists were able to do (Bailyn, 2014). Stephen achieved this
with the added disadvantage of his illness and that what makes his ability to do the things that he
did even more astonishing,” he added.
The material to be added, I will add some more scientific statements from Hawking. He will be
elaborating more on black holes. Apart from that, I wish to do more elaborate and extensive
research on black holes from sources that are different from those authored by Hawking.

8
BLACK HOLES AND HAWKING RADIATION
References
Bailyn, C. D. (2014). What Does a Black Hole Look Like? New York: Princeton University
Press.
Blundell, K. (2015). Black Holes: A Very Short Introduction. Oxford: Oxford University Press.
Calmet, X. (2013). Quantum Black Holes. Kansas: Springer Science & Business Media.
Hawking, S. (2016). Black Holes. New York: Random House Publishing Group.
Ngampitipan, T. (2014). Rigorous Bounds on Greybody Factors for Various Types of Black
Holes. Salt Lake: Chulalongkorn University.
Ong, Y. C. (2015). Evolution of Black Holes in Anti-de Sitter Spacetime and the Firewall
Controversy. Beijing: Springer.
Susskind, L. (2014). The Black Hole War: My Battle with Stephen Hawking to Make the World
Safe for Quantum Mechanic. London: Little, Brown.
Xavier, C. (2014). Quantum Aspects of Black Holes. Salt Lake: Springer.