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) or 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.
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.
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
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.
http://spacelink.msfc.nasa.gov -
/Educational.Services/Educational.Publications/Educational.Horizons.Newsletter/ 92-01-01.Vol.1.No.1
/NASA.News/NASA.News.Releases /95.Press.Releases/95-06.News.Releases/95-06-12.Primordial.Helium.Detected
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.
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:
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.
NOW WHAT?
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.
GLOSSARY
Baryons-- common particles including photons and neutrinos created at approximately 10^-33 seconds after the Big BangDeuterium-- 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
References:
Literature
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
NASAhttp://spacelink.msfc.nasa.gov -
/Educational.Services/Educational.Publications/Educational.Horizons.Newsletter/ 92-01-01.Vol.1.No.1
/NASA.News/NASA.News.Releases /95.Press.Releases/95-06.News.Releases/95-06-12.Primordial.Helium.Detected
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