Running Head: STEPHEN HAWKING
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Stephen Hawking
Charles L. Despain
Salt Lake Community College
STEPHEN HAWKING
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Abstract
This paper will be discussing the life and scientific contributions to the history of physics by
Stephen Hawking. He is a British theoretical physicist, cosmologist, and an author. He is
currently the Director of Research at the Centre for Theoretical Cosmology at The University of
Cambridge. Although he was diagnosed with Amyotrophic Lateral Sclerosis (ALS), or Lou
Gehrig’s Disease, he has influenced many of the scientific fields. Physics would not be where it
is today without the intellectual contributions of Hawking. Some of his breakthrough
contributions to the history of physics include his properties of expanding universes, Hawking
Radiation, the Penrose-Hawking Theorems, and his theories of the Hartle-Hawking State.
STEPHEN HAWKING
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Stephen Hawking
Stephen Hawking is a British theoretical physicist, cosmologist, and an author. He was
diagnosed with Amyotrophic Lateral Sclerosis (ALS), or Lou Gehrig’s disease, at a young age.
Despite the hardships of this disease as it has gradually paralyzed him, Hawking has
accomplished many great things, as physics would not be where it is today without the
intellectual contributions of Stephen Hawking. Hawking is responsible for the Properties of
Expanding Universes, Hawking Radiation, the Penrose-Hawking Theorems, and the HartleHawking State.
In 1965, when he was only twenty-three years old, Hawking released a thesis on
Properties of Expanding Universes. A few years before, microwaves were discovered coming
from space. Scientists concluded that this was the remnants of a very hot and dense early
universe, which had cooled as it had expanded leaving only these small microwaves. It was then
that the Penrose-Hawking Theorems were developed. These theorems stated that the universe did
have a beginning, and that the universe was a singularity. These theorems meant that Einstein’s
General Theory of Relativity brake down at the singularity or, more widely believed by
scientists, that Einstein’s theorems brake down in the strong gravitational fields of the early
universe. It was not until 1970 that Penrose and Hawking published a proof that the universe had
begun as a singularity. If the universe fits the models of physical cosmology according to
Alexander Friedmann and obeys the general theory of relativity, then the universe must have
begun as a singularity.
In 1975, Hawking published a theory of black body radiation probably produced by black
holes, or Hawking Radiation. This theory states that black holes produce a radiation of particles
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in proportion to their size. The bigger the black hole, the less radiation produced. The smaller the
black hole, the more radiation produced. This theory also predicts that as a black hole gives off
radiation, it is slowly deteriorating. This means that the smaller the black hole, the faster the
deterioration. Something else to take into consideration is the bigger the black hole, the faster it
can “suck” particles in and the less chance that particulate radiation can escape. It is theorized
that at the horizon of the hole, particles are produced in pairs of particles and anti-particles.
These pairs instantly consume each other, however sometimes one of the particles can escape
before it is consumed by its pair. Many scientists debate this as it cannot yet be proven and a
small black hole that is quickly deteriorating has not yet been found to survey and study.
The Hurtle-Hawking proposals of No-Boundary and the Hurtle-Hawking State arose in
1983. In a fashion similar to quantum mechanics, Hurtle and Hawking computed the
probabilities and made a wave-function for all the possible universes. The wave-function shows
a high value, or high probability, for our universe and other low values, or low probabilities for
other possible and parallel universes. The other universes are expected to have different physical
constants, and to be lifeless. The Hurtle-Hawking State is the proposal that because a beginning
has to do with time, and time theoretically did not exist until after the big bang, the universe has
no beginning, or at least a beginning which we cannot understand. The universe was a singularity
in space and time until the big bang. The controversial point of this proposal was that it claims
the universe is closed. If the universe was closed, then how is the universe expanding as it has
been proven? The concept of a closed universe expanding can be compared to a balloon.
However a closed universe would eventually stop expanding, and collapse upon itself. It also
should be noted that the further the universe expands, the faster the expansion is happening.
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Although many of Hawking’s hypotheses and theories are being debated, many of which
have been proven and are being used to further develop fields such as general relativity and
quantum gravity. Even Hawking’s controversial ideas have been extremely helpful to the
industry as his ideas were very unique and opened many doors of thought for different
possibilities of the universe. The strides made by physics today, specifically quantum physics, is
reliant on Hawking’s principals.
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References
Baez, John. 1994. (Modified by Schmelzer, Ilja, 1997)
University of California, Riverside. Hawking Radiation,
math.ucr.edu/home/baez/physics/Relativity/Blackholes/hawking.html
Hawking, Stephen. Lecture.
The Origin of the Universe
www.hawking.org.uk
Hawking, Stephen. Lecture.
The Beginning of Time
www.hawking.org.uk/the-beginning-of-time.html
University of Victoria
Hartle-Hawking
web.uvic.ca/̴ jtwong/Hartle-Hawking.html
Wall, Aron.
Did the Universe Begin II: Singularity Theorems
www.wall.org/ ̴ aron/