This document discusses evidence that supports the Big Bang theory of the origin and expansion of the universe. It describes how observations by Hubble, Slipher and others established that galaxies are moving away from each other, indicating an expanding universe. Other evidence mentioned includes the cosmic microwave background radiation, cosmic neutrino background, and use of supernovae as standard candles. The document also explores some philosophical questions raised by concepts like the primordial singularity and infinities in theories of cosmology.

1. First Principles
“Man is equally incapable of seeing the nothingness from which he
emerges and the infinity in which he is engulfed.” – Blaise Pascal
Cosmology is a field where physics and the metaphysical collide. As the
study of everything, it is a area that often threatens to follow esoteric
tangents into the spiritual. Cosmology also has come to a point where
human comprehension is perhaps not enough, yet. The origin of our
universe, and possibly everything to ever exist, was christened the Big
Bang by Fred Hoyle in 1949.
The big bang is a monumentally important concept. Understanding the
conditions in which our very universe formed has deep implications for a
deeper universal understanding, both scientific and spiritual.
Decades of evidence now suggest that the Universe is expanding. Simple
deduction indicates that an expanding universe must be expanding
outwards from something. It is that something it came from, and the
reason why, which poses one of science’s greatest unfolding mysteries.
Einstein’s contribution to expanding universe

2. When the General Theory of Relativity was proposed in 1915, the state of
the observational knowledge was not yet ready to put his theory to the
test.
Soon after it’s completion, Einstein began using these equations to
describe the global properties of the whole Universe. He soon came to a
serious quandary. If, at a given time, all the galaxies in the Universe are
stationary, and provided the Universe was finite in size, mutual
gravitational attraction would cause them to begin to converge inwards;
the universe would collapse in on itself. It could not remain static. To
have the universe remain unchanged would be like a pencil balanced on
its point; possible, but highly unlikely and not liable to last for very long.
One way or another, it would fall.
Einstein found he could ‘fix’ this problem by adding a simple constant
term to the equations. An invisible force to immobilize the universe. This
"cosmological constant" Einstein admitted, was only "a hypothetical
term." It was "not required by the theory as such nor did it seem natural
from a theoretical point of view”(Einstein 2007)
Observational Evidence Arrives..
In the 1910s, Vesto Slipher was the first to observe the shift of spectral
lines of galaxies, making him the discoverer of galactic motion. (Slipher
1913). However, Slipher’s measurements of radial velocities had
effectively reached their limit, his 24-inch refractor at the Lowell
Observatory , unable to penetrate further into space and record spectra
from the numerous fainter nebulae. Enter Edwin Hubble, and his 100 inch
telescope on Mount Wilson..

3. Hubble’s Contribution
"The redshift of distant nebulae has smashed my old construction (the
cosmological constant) like a hammer blow" – Einstein
In 1925 Hubble published an extensive paper, in which he reported his
observations of NGC 6822. Using Cepheid Variables as standard candles
to measure distance he determined a figure of 700 000 light-years and
concluded: “N.G.C. 6822 lies far outside the limits of the galactic
system”(E. P. Hubble 1925)
This was a monumental moment; this was the first system beyond the
Magellanic Clouds to have its distance accurately determined. It instantly
changed our cosmological understanding. The galaxy was no longer the
universe. Who knew how many more galaxies there could be?
By 1929, the work of Hubble had established our present picture of an
expanding universe, consisting of galaxies moving away from one
another. For his dissertation Hubble decided to study a series of nebulae.
In a now famous diagram, he plotted the redshifts (velocities) of the

4. receding galaxies against their distances, and thus Hubble’s Law was
written.
Hubble’s Law:
Galaxies are receding from us at a velocity that is proportional to their
distance from us. Galaxies appear to be moving away from us at speeds
proportional to their distance. This observation supports the expansion of
the universe and is a powerful argument that the universe was once
compacted.
Too much knowledge?
I would compare the implications of expanding space to our discovery
that the world was not flat. Just because it appears one way does not
make it so. In cosmology, intuitive was not enough, and we must once
again acknowledge the possibility that our minds may not be capable of
comprehending the bigger picture.
A common trend throughout history is denial of the truth, if the truth
challenges doctrine or, if it hurts too much. Both Einstein and Hubble had
trouble facing up to the implications of their discoveries.
In 1917 de Sitter produced a set of equations that could describe the

5. universe as expanding. An expanding universe implied a beginning,
which Einstein did not appreciate. In correspondence with him, Einstein
stated frankly of a non-static universe; “To admit such possibilities seems
senseless.”(Edwards 2001, p.19) This would not be the first time that
Einstein’s humanity clashed with the science he was developing.
Hubble was a cautious man and determined to leave a ‘perfect’ scientific
legacy by making no predictions that could later be mistaken.
Lick Observatory astronomer C Donald Shane later revealed "Hubble
had a desire to show that the red shift was not actually expansion,
because he seemed always to be seeking some other explanation for
it"(Bartusiak 2009)
In his Rose Memorial Lectures on Hubble said of redshifts: "Their
significance is still uncertain" – and described the expanding universe as
a "dubious world"(Edwin Hubble 1937)
Despite Hubble’s own personal reservations with his discovery, redshifts
brought about big changes.
A contemporary scientific theory was Fred Hoyle’s steady state Universe.
An old astronomical paradigm of an eternal unchanging universe, it all
but had its foundations pulled out from underneath it by Hubble’s
observations. However, galactic motion’s implications were to go far
deeper…
The Plurality Of Worlds, Continued..
Hubble’s evidence of an expanding universe disrupted both religious and
scientific beliefs.
His observations contributed to an increasingly larger cosmos, and
perhaps by comparison, an increasingly small place in this universe for
humanity. In 1543 Copernicus’ De Revolutionibus smashed the belief that
the earth was the centre of the universe. Hubble had now showed that this
universe was much, much larger than we thought. It was becoming
evident that we were not particularly unique in the cosmos (at least not in
a cosmological sense).
Expanding from what?
"The actual point of creation lies outside the scope of presently known
laws of physics" - Stephen Hawking
"The instant of creation remains unexplained." - Alan Guth

6. In 1922, Alexander Friedman corrected an error in Einstein’s field
equations. His solutions of an open or closed universe argued strongly for
a universe in motion. (Friedman 1922)
Then, in 1927 Lemaître proposed his 'hypothesis of the primeval atom'
(Milne 1949). He had independently derived the same expanding
mathematics that Friedman had. Their calculations would later be
combined in the FLRW metric. This standard model of cosmology
describes an expanding or contracting universe.
Mathematical and observational evidence was mounting. An awkward
question started to rear its head. If the universe was in motion, it is
changing, and furthermore if expanding, what was it moving away from?
Einstein’s response to the idea of an expanding universe was essentially
the same to both men’s mathematics: he found no errors in the
mathematics of the theory, yet he was convinced that from the physical
point of view it was “tout à fait abominable”’(Kragh 2007, p.56).
However, physical law does not care for human sensitivity. Decades later,
Hawking and Penrose mathematically demonstrated that every solution to
the general relativity’s equations guarantees the existence of a singular
boundary for space and time in the past. This is now known as the
"singularity theorem"(Hawking 1976). The ‘primeval atom’ now existed
in a strong mathematic framework.
Questions Posed By The Origin – Nothing and Infinites?
The singularity presents ideas that are extremely hard to comprehend.
Areas that take us into a domain of philosophy and questions that are hard
to answer with science.
Some believe that space didn’t exist before the big bang. This in itself is
a perceptual and philosophical challenge to human instinct. What is
nothing? I do not think we can comprehend it. The closest to nothing I
can imagine is blackness. But blackness can be defined, it is a colour, or
an absence of light.
In wrestling with the nature of nothing Descartes stated; I think therefore
I am; postulating that the foundations of knowing reality to be true are
that we can think about them. Extending this idea further, perhaps the fact
that we think there could have been something at origin, means that
perhaps it exists at least as a perception of collective human belief, but

7. maybe not in a physical reality?
Can nothing exist? Surely in existing it is something, it exists as nothing,
and therefore is. Therefore there must have been something, even if
defined as nothing. These are rhetorical arguments which do not offer
anything in the way of an explanation, but may be important in a more
philosophical sense, helping humans deal with the great uncertainties
inherent in facing oblivion, and using semantics to challenge and expand
our comprehension.
Infinites..
If something grows in size, by definition it takes forever to become
infinite. Therefore, if our Universe is infinite in size today then it must
also have been infinite in the past. Furthermore, it must already have
been infinite in size at the moment of the Big Bang.
Though the primordial singularity is described an infinitely small, at this
point it may have been everything. This introduces the philosophical
concept of differing infinites, which at the very least utterly
counterintuitive to human comprehension.
Time
Our definition of time is another victim of the big bang. Can we say that
the Big Bang ‘happened’ at some definite moment in time? The problem
is in General Relativity, time itself is hypothesized to have began at the
Big Bang. Furthermore, in an area of infinite mass (such as the primordial
singularity), relativity demands that gravitational time dilation would
essentially cause time stand still.
The Big Bang cannot even be considered as the ‘first event’ since that
would require it to have happened within time. If time was essentially
static at this point (essentially moving infinitely slow), ‘when’ did the big
bang happen?
Einstein himself held unusual views about time. He believed the flow of
time to be illusory and even expressed it when consoling the bereaved
widow of a close friend. He told her that she should take comfort
knowing that the present moment is no more special than any other in the
past or the future; all times exist together.
This however doesn’t make it any easier for the layman to grasp.

8. More Big Bang Questions
Apart from a string of existential headaches, the origins of the big bang
have been the catalyst for an explosion of new physical theories. The
questions asked by an expanding universe have produced many wildly
disparate, tentative answers at the cutting edge of science.
One theory says the universe began as the result of the motion of a
particle falling towards a black hole singularity, and that our universe
exists locked inside an Einstein-Rosen black hole.(Poplawski 2009)
Another argues the big bang was the result of a collision between two
membranes floating in higher-dimensional space; an idea dubbed the
Ekpyrotic Universe. (Khoury et al. 2001)
Yet Another says that our universe was created as a bubble in energy
fluctuations, in the seething quantum foam of a different, parent universe.
This multiverse has no beginning or ending, and the theory is known as
the Chaotic Inflation.(Linde 1986)
Asides from the three mentioned above there are many, many more
theories dealing with origin.
Evidence supporting the big bang
As optical technology and mathematical tools have evolved, the
expanding universe has been strengthened by observational evidence.
Redshift
The first piece of evidence comes from Hubble’ Law.
When a large number of galaxies are studied, it might be expected that
roughly half would be blue-shifted and half red-shifted. This would be if
the overall universe were static and the galaxies were moving randomly.
This however, is not the case. On a smaller scale, galaxies close to the
milky-way are converging with mutual gravitational attraction (Courteau
2000), but the majority of galactic observations see them moving away in
accordance with Hubble’s law(Collins et al. 1986)
The ratio of the velocity and a galaxy’s distance is now established at a
constant, termed the Hubble parameter. Its value is now estimated to be
around seventy kilometers per second per megaparsec, where a
megaparsec is the distance light travels in about three million years.

9. Cosmic background radiation
Secondly if the universe was initially extremely hot, as the singularity
suggests, we should notice some remnant of this heat.
In 1948 George Gamow predicted that if the Big Bang had occurred, the
radiation from it should be observable in the microwave portion of the
spectrum(Alpher et al. 1948). However, the technology for observing at
these wavelengths did not yet exist to test his theory.
In 1965, Radioastronomers Arno Penzias and Robert Wilson accidentally
discovered a 2.725 degree Kelvin Cosmic Microwave Background
radiation (CMB) throughout the entire universe. This is thought to be the
energy that Gamow predicted. Penzias and Wilson shared in the 1978
Nobel Prize for Physics for their discovery.
Later observations of cyanogen excitation in molecular clouds provide
further support for the CMB. Cyanogen is a gas which responds to
photons emitted from the CMB. The observed level of cyanogen
excitation is consistent with direct satellite measurements of the cosmic
microwave background radiation (Roth & Meyer 1995), and also agrees
remarkably well with the Cosmic Background Explorer Satellite’s
(COBE) measurements.

10. Spectrum of the Cosmic Microwave Background Radiation as measured
by the COBE satellite. Within the quoted errors, the spectrum is precisely
that of a perfect black-body at radiation temperature T = 2.728 ± 0.002
K(Fixsen & Mather 2002)
Although we are unable to ‘see’ it, all of this is the footprint for our
primordial fireball (a black body object) and strong evidence for the hot
big bang hypothesis.
Cosmic Neutrino Background
Additional evidence comes from the existence of ripples of primordial
origin in the Cosmic Neutrino Background (Trotta & Melchiorri 2005).
Measurement of these ripples was made by combining data produced by
the NASA WMAP (Wilkinson Microwave Anisotropy Probe) satellite
and the Sloan Digital Sky Survey. These neutrinos are thought to have
decoupled from the singularity when the universe was around 1-2
seconds old. It is estimated that today the CNB has a temperature of
roughly 1.95K

11. Standard Candles In Distant Galaxies
All type 1a supernovas are believed to shine with approximately the same
absolute magnitude of brightness. The absolute magnitude for the Type
Ia supernovae has been calibrated to be
M = -19.33 0.25 (Universe Review n.d.)
Suppose one observes 2 such supernova, and one appears to be 4 times
brighter than the other. If the expansion of space were constant, the
redshift of the dimmer supernova would be twice the redshift of the
brighter one.
Graphing redshift vs. brightness would yield a straight line, and if the
expansion were decelerating, the line would curve downward.
Studies of these supernova show an upward trend (an accelerating
universe) (Phillips 1993). Because of this, scientists tentatively conclude
that the expansion is accelerating. However, there is significant variation
in the brightness of the supernovas; the intrinsic colours of Type Ia
supernovae at maximum light are not identical, and the curve of the
graph is very close to a straight line. More measurements at greater
distances are required before we can be completely certain of the results.
Olber’s Paradox
If the galaxies were distributed according to the inverse square law in
space, it is calculated that the light flux in the night sky would be at least
as bright as the average star. ‘Dark’ background space would glow with
the light from an infinite field of stars (Wesson 1991).
However, the expansion of the universe ensures that the flux is constantly
reduced as the universe expands, the light has further to travel,
consequentially it is made fainter.
Thus, the Visible Universe (our tiny corner of space) does have an
observable edge (a limit on how much light gets to us) even if the
Universe as a whole does not. This is caused by expansion.
Finally, we can turn Olbers’ paradox on its head and make the
statement the real proof that the Big Bang happened is that it gets
dark at night. (Al-Khalili 1999)
Conclusion
Today ample evidence outweighs challenges to the expanding universe

12. hypothesis. The big bang and expanding universe are arguably the new
cosmic paradigm. However, the scenario poses more questions than it has
answered. Mainly in what caused the event, and what could have
happened before it. In this way, these theories are the stepping stones for
more scientific understanding to come. Understanding conditions at
origin could be very important in formulating a Grand Unified Theory
which could very possibly unite all the fundamental interactions in
physics.
Though we still have ample questions to answer, the relentless march of
science has contributed to less and less uncertainty in understanding the
Universe’s origins. Religious fundamentalists may be unwilling to
confront this directly, but as extent of the known Universe expands, the
God of The Gaps shrinks. With a coherent understanding of the
beginning of the universe, Religion’s place may be confined purely to
dealing with the end of the universe and the death of physical
consciousness (if such a thing is true). And Perhaps one day science will
get to that as well?
Whatever Happens, Everything Ends.
Cosmology is a purely observational science, it is very hard for us to
create physical experiments which simulate the early universe. This is
because we cannot observe past the point that photons were energetically
bound in the early universe (the cosmic dark age), regardless of how good

13. our optics become. Nor can we properly simulate the bizarre conditions
in which the universe began, as we may never know what they are.
However, technology such as particle accelerators may allow us to peak
into the fundamental building blocks of matter by smashing hadrons into
the quark gluon plasma which is thought to have permeated the universe
at origin (Masera & Alice Collaboration Project 2003). This may help us
answer questions associated with the singularity; such as the origin of
mass, where missing antimatter may have gone, and perhaps allow us a
peak at extra dimensions.(CERN 2008)
Finally, an expanding universe also deals with issue of mortality (by
making it unavoidable, on a cosmic scale!). At this point, there are 3 main
scenarios for the end. A Big Crunch in which we are annihilated in a
contracting, superheated, superdense universe. A Big Rip in which a
repulsive force in accelerating universe eventually overcomes all the
other forces, and literally tears matter and all it’s constituents apart.
Finally there is Heat Death, in which eventual entropy conquers
everything, and we are left with a cold ‘dead’ universe where even
fundamental particles have decayed. The full transition of mass to energy
is made complete.
Many physicists, such as Hawking; see time as a measurement of
entropy. The universe, in its current expanding direction, is becoming
more and more disordered- entropy is increases and has been doing so
since the inception of the universe, Like a sun that cools into cosmic
darkness, a building that surrenders to gravity, or a person who succumbs
to age, as time progresses, the ultimate movement is always towards
disorder.
Perhaps it isn’t elegant, perhaps it’s hard to deal with, but who said the
universe had to be fair? An universe in motion may be an easy concept to
grasp intellectually, but it’s eschatological implications could be
terrifying to the human mind that cannot properly comprehend infinites
or the void.
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