Chris LaRocco and Blair Rothstein present:
THE BIG BANG:
The Hubble Telescope's deepest view of the universe teaches us about the beginning
We certainly know that our universe exists, however, this knowledge alone has not satisfied mankind's quest for further
understanding. Our curiosity has led us to question our place in this universe and furthermore, the place of the universe
itself. Throughout time we have asked ourselves these questions: How did our universe begin? How old is our universe? How
did matter come to exist? Obviously, these are not simple questions and throughout our brief history on this planet much time
and effort has been spent looking for some clue. Yet, after all this energy has been expended, much of what we know is still
We have, however, come a long way from the mystical beginnings of the study of cosmology and the origins of the universe.
Through the understandings of modern science we have been able to provide firm theories for some of the answers we once called
hypotheses. True to the nature of science, a majority of these answers have only led to more intriguing and complex questions.
It seems to be inherent in our search for knowledge that questions will always continue to exist.
Although in this short chapter it will be impossible to tackle all of the questions concerning the creation of everything
we know as reality, an attempt will be made to address certain fundamental questions of our being. It will be important to
keep in mind that all of this information is constantly being questioned and reevaluated in order to understand the universe
more clearly. For our purposes, through an examination of what is known about the Big Bang itself, the age of the universe,
and the synthesis of the first atoms, we believe that we can begin to answer several of these key questions.
THE BIG BANG
One of the most persistently asked questions has been: How was the universe created? Many once believed that the universe
had no beginning or end and was truly infinite. Through the inception of the Big Bang theory, however,no longer could the
universe be considered infinite. The universe was forced to take on the properties of a finite phenomenon, possessing a history
and a beginning.
About 15 billion years ago a tremendous explosion started the expansion of the universe. This explosion is known as the
Big Bang. At the point of this event all of the matter and energy of space was contained at one point. What exisisted prior
to this event is completely unknown and is a matter of pure speculation. This occurance was not a conventional explosion but
rather an event filling all of space with all of the particles of the embryonic universe rushing away from each other. The
Big Bang actually consisted of an explosion of space within itself unlike an explosion of a bomb were fragments are thrown
outward. The galaxies were not all clumped together, but rather the Big Bang lay the foundations for the universe.
The origin of the Big Bang theory can be credited to Edwin Hubble. Hubble made the observation that the universe is continuously
expanding. He discovered that a galaxys velocity is proportional to its distance. Galaxies that are twice as far from us move
twice as fast. Another consequence is that the universe is expanding in every direction. This observation means that it has
taken every galaxy the same amount of time to move from a common starting position to its current position. Just as the Big
Bang provided for the foundation of the universe, Hubbles observations provided for the foundation of the Big Bang theory.
Since the Big Bang, the universe has been continuously expanding and, thus, there has been more and more distance between
clusters of galaxies. This phenomenon of galaxies moving farther away from each other is known as the red shift. As light
from distant galaxies approach earth there is an increase of space between earth and the galaxy, which leads to wavelengths
In addition to the understanding of the velocity of galaxies emanating from a single point, there is further evidence for
the Big Bang. In 1964, two astronomers, Arno Penzias and Robert Wilson, in an attempt to detect microwaves from outer space,
inadvertently discovered a noise of extraterrestrial origin. The noise did not seem to emanate from one location but instead,
it came from all directions at once. It became obvious that what they heard was radiation from the farthest reaches of the
universe which had been left over from the Big Bang. This discovery of the radioactive aftermath of the initial explosion
lent much credence to the Big Bang theory.
Even more recently, NASAs COBE satellite was able to detect cosmic microwaves eminating from the outer reaches of the universe.
These microwaves were remarkably uniform which illustrated the homogenity of the early stages of the universe. However, the
satillite also discovered that as the universe began to cool and was still expanding, small fluctuations began to exist due
to temperature differences. These flucuatuations verified prior calculations of the possible cooling and development of the
universe just fractions of a second after its creation. These fluctuations in the universe provided a more detailed description
of the first moments after the Big Bang. They also helped to tell the story of the formation of galaxies which will be discussed
in the next chapter.
The Big Bang theory provides a viable solution to one of the most pressing questions of all time. It is important to understand,
however, that the theory itself is constantly being revised. As more observations are made and more research conducted, the
Big Bang theory becomes more complete and our knowledge of the origins of the universe more substantial.
THE FIRST ATOMS
Now that an attempt has been made to grapple with the theory of the Big Bang, the next logical question to ask would be
what happened afterward? In the minuscule fractions of the first second after creation what was once a complete vacuum began
to evolve into what we now know as the universe. In the very beginning there was nothing except for a plasma soup. What is
known of these brief moments in time, at the start of our study of cosmology, is largely conjectural. However, science has
devised some sketch of what probably happened, based on what is known about the universe today.
Immediately after the Big Bang, as one might imagine, the universe was tremendously hot as a result of particles of both
matter and antimatter rushing apart in all directions. As it began to cool, at around 10^-43 seconds after creation, there
existed an almost equal yet asymmetrical amount of matter and antimatter. As these two materials are created together, they
collide and destroy one another creating pure energy. Fortunately for us, there was an asymmetry in favor of matter. As a
direct result of an excess of about one part per billion, the universe was able to mature in a way favorable for matter to
persist. As the universe first began to expand, this discrepancy grew larger. The particles which began to dominate were those
of matter. They were created and they decayed without the accompaniment of an equal creation or decay of an antiparticle.
As the universe expanded further, and thus cooled, common particles began to form. These particles are called baryons and
include photons, neutrinos, electrons and quarks would become the building blocks of matter and life as we know it. During
the baryon genesis period there were no recognizable heavy particles such as protons or neutrons because of the still intense
heat. At this moment, there was only a quark soup. As the universe began to cool and expand even more, we begin to understand
more clearly what exactly happened.
After the universe had cooled to about 3000 billion degrees Kelvin, a radical transition began which has been likened to
the phase transition of water turning to ice. Composite particles such as protons and neutrons, called hadrons, became the
common state of matter after this transition. Still, no matter more complex could form at these temperatures. Although lighter
particles, called leptons, also existed, they were prohibited from reacting with the hadrons to form more complex states of
matter. These leptons, which include electrons, neutrinos and photons, would soon be able to join their hadron kin in a union
that would define present-day common matter.
After about one to three minutes had passed since the creation of the universe, protons and neutrons began to react with
each other to form deuterium, an isotope of hydrogen. Deuterium, or heavy hydrogen, soon collected another neutron to form
tritium. Rapidly following this reaction was the addition of another proton which produced a helium nucleus. Scientists believe
that there was one helium nucleus for every ten protons within the first three minutes of the universe. After further cooling,
these excess protons would be able to capture an electron to create common hydrogen. Consequently, the universe today is observed
to contain one helium atom for every ten or eleven atoms of hydrogen.
While it is true that much of this information is speculative, as the universe ages we are able to become increasingly
confident in our knowledge of its history. By studying the way in which the universe exists today it is possible to learn
a great deal about its past. Much effort has gone into understanding the formation and number of baryons present today. Through
finding answers to these modern questions, it is possible to trace their role in the universe back to the Big Bang. Subsequently,
by studying the formation of simple atoms in the laboratory we can make some educated guesses as to how they formed originally.
Only through further research and discovery will it be possible to completely understand the creation of the universe and
its first atomic structures, however, maybe we will never know for sure.
AGE OF THE UNIVERSE
We now have something of a handle on two of the most important quandaries concerning the universe; however, one major question
remains. If the universe is indeed finite, how long has it been in existence? Again, science has been able to expand upon
what it knows about the universe today and extrapolate a theory as to its age. By applying the common physical equation of
distance over velocity equaling time, which again uses Hubbles observations, a fairly accurate approximation can be made.
The two primary measurements needed are the distance of a galaxy moving away from us and that galaxys red shift. An unsuccessful
first attempt was made to find these distances through trigonometry. Scientists were able to calculate the diameter of the
Earths orbit around the sun which was augmented through the calculation of the Suns motion through our own galaxy. Unfortunately,
this calculation could not be used alone to determine the enormous distance between our galaxy and those which would enable
us to estimate the age of the universe because of the significant errors involved.
The next step was an understanding of the pulsation of stars. It had been observed that stars of the same luminosity blinked
at the same rate, much like a lighthouse could work where all lighthouses with 150,000 watt light bulbs would rotate every
thirty seconds and those with 250,000 watt light bulbs would rotate every minute. With this knowledge, scientists assumed
that stars in our galaxy that blinked at the same rate as stars in distant galaxies must have the same intensity. Using trigonometry,
they were able to calculate the distance to the star in our galaxy. Therefore, the distance of the distant star could be calculated
by studying the difference in their intensities much like determining the distance of two cars in the night. Assuming the
two cars headights had the same intensity, it would be possible to infer that the car whose headlights appeared dimmer was
farther away from the observer than the other car whose headlights would seem brighter. Again, this theory could not be used
alone to calculate distance of the most far-away galaxies. After a certain distance it becomes impossible to distinguish individual
stars from the galaxies in which they exist. Because of the large red shifts in these galaxies a method had to be devised
to find distance using entire galaxy clusters rather than stars alone.
By studying the sizes of galaxy cluster that are near to us, scientists can gain an idea of what the sizes of other clusters
might be. Consequently, a prediction can be made about their distance from the Milky Way much in the same way the distance
of stars was learned. Though a calculation involving the supposed distance of the far-off cluster and its red shift, a final
estimation can be made as to how long the galaxy has been moving away from us. In turn, this number can be used inversely
to turn back the clock to a point when the two galaxies were in the same place at the same time, or, the moment of the Big
Bang. The equation generally used to show the age of the universe is shown here:
(distance of a particular galaxy) / (that galaxys velocity) = (time)
4.6 x 10^26 cm / 1 x 10^9 cm/sec = 4.6 x 10^17 sec
This equation, equaling 4.6 x 10^17 seconds, comes out to be approximately fifteen billion years. This calculation is almost
exactly the same for every galaxy that can be studied. However, because of the uncertainties of the measurements produced
by these equations, only a rough estimate of the true age of the universe can be fashioned. While finding the age of the universe
is a complicated process, the achievement of this knowledge represents a critical step in our understanding.
In summary, we have made a first attempt at explaining the answers that science has revealed about our universe. Our understanding
of the Big Bang, the first atoms and the age of the universe is obviously incomplete. As time wears on, more discoveries are
made, leading to infinite questions which require yet more answers. Unsatisfied with our base of knowledge research is being
conducted around the world at this very moment to further our minimal understanding of the unimaginably complex universe.
Since its conception, the theory of the Big Bang has been constantly challenged. These challenges have led those who believe
in the theory to search for more concrete evidence which would prove them correct. From the point at which this chapter leaves
off, many have tried to go further and several discoveries have been made that paint a more complete picture of the creation
of the universe.
Recently, NASA has made some astounding discoveries which lend themselves to the proof of the Big Bang theory. Most importantly,
astronomers using the Astro-2 observatory were able to confirm one of the requirements for the foundation of the universe
through the Big Bang. In June, 1995, scientists were able to detect primordial helium, such as deuterium, in the far reaches
of the universe. These findings are consistent with an important aspect of the Big Bang theory that a mixture of hydrogen
and helium was created at the beginning of the universe.
In addition, the Hubble telescope, named after the father of Big Bang theory, has provided certain clues as to what elements
were present following creation. Astronomers using Hubble have found the element boron in extremely ancient stars. They postulate
that its presence could be either a remnant of energetic events at the birth of galaxies or it could indicate that boron is
even older, dating back to the Big Bang itself. If the latter is true, scientists will be forced once again to modify their
theory for the birth of the universe and events immediately afterward because, according to the present theory, such a heavy
and complex atom could not have existed.
In this manner we can see that the research will never be truly complete. Our hunger for knowledge will never be satiated.
So to answer the question, what now, is an impossibility. The path we take from here will only be determined by our own discoveries
and questions. We are engaged in a never-ending cycle of questions and answers where one will inevitably lead to the other.
COBE continues to search the outer reaches of the universe
It is extremely difficult to separate this subject of science from daily existential pondering. Everyone at some point
in time has grappled with the question of why we are here? Some have found refuge in the sheer philosophic nature of this
question while others have taken a more scientific approach. These particular wanderers have taken the question to a higher
level, concentrating not only on human existence but the existence of everything we know as real.
If you sit and try to imagine the whole of the entire universe it would be mind-boggling. However, science has now told
us that the universe is, in fact, finite, with a beginning, a middle, and a future. It is easy to get caught up in the large
scale of the issue in discussing years by the billions, yet, this time still passes. As we travel through our own lives here
on Earth, we also travel through the life of our universe.
In this chapter, we have made some attempts to explain this journey. It is odd that we will never truly know how it began.
We can only speculate and give our best guess. Through our own devices we have been able to produce evidence that these guesses
are close to the truth. But centuries from now, will the human race compare us to those who once thought of the Earth as the
center of the universe?
Baryons-- common particles including photons and neutrinos created at approximately 10^-33 seconds after the Big
Deuterium-- a heavy isotope of hyrogen containing on proton and one neutron
Hadrons-- composite particles such as protons and neutrons forming after the temperature drops to 300 MeV
Leptons-- light particles existing with hadros including electrons, neutrinos and photons
Red Shift-- shift toward the red in the spectra of light reaching us from the stars in distant galaxies
Tritium-- transitional element between deuterium and the formation of a helium nucleus
Kaufmann, William J., III. Galaxies and Quasars. San Fransisco: W.H. Freeman and Company, 1979.
Silk, Joseph. A Short History of the Universe. New York: Scientific American Library, 1994.
Taylor, John. When the Clock Struck Zero. New York: St. Martins Press, 1993.
Trinh, Xuan Thuan. The Birth of the Universe: The Big Bang and After. New York: Harry N. Abrams, Inc., 1993.
World Wide Web
Publications/Educational.Horizons.Newsletter/ 92-01-01.Vol.1.No.1 (not online available anymore)
/NASA.News/NASA.News.Releases /95.Press.Releases/95-06.News.Releases/95-06-12.Primordial.Helium.Detected outdated, moved to
ASTRO-2 PROVIDES FIRST DEFINITIVE DETECTION OF PRIMORDIAL HELIUM
Regrettably, NASA Spacelink has moved to http://www.nasa.gov/, for this reason the links included in the above article are outdated.
For more information see
NASA search: Big Bang
NASA search: Hubble