How Big is the Universe? How Old is it?
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- rodstradamus
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Faster Than Light: Part One
Dec 15, 2009
How big is the Universe? How old is it?
Today, cosmology is dominated by the Big Bang theory. The theory's major premise is that there was once a void containing no matter, no space, and no time. For some reason not explained by the scientists who support the theory, an irruption of energy from another realm of existence replaced the void with what eventually became the present Universe.
The Big Bang theory was postulated because the astronomer Edwin Hubble, using the 100-inch telescope at Mt. Wilson observatory, believed that he had observed remote galaxies receding from the Milky Way. The most surprising piece of his recorded data was not the recession itself, but the high velocities associated with his measurements. According to his calculations, some galaxies were traveling away from his observatory at thousands of kilometers per second.
Hubble arrived at his conclusion because of what was later to be called the "redshift" of light frequencies in spectrograms from his galactic images. Adapting the Doppler effect (named for the Austrian physicist Christian Doppler, who came up with the idea in 1842) to the spectra of various galaxies, Hubble thought that the change in location of particular elemental signatures called Fraunhofer lines (for the German physicist Joseph von Fraunhofer) indicated that the lightwaves had been shifted toward the red end of the spectrum by an apparent recessional velocity.
Fraunhofer lines are supposed to occur at specific frequencies identified in the spectrum by the kind of element that is absorbing the light. If they are in a different location, then they have been Doppler-shifted because of the element's acceleration. This forms the backbone of galactic-scale distance calculations and the supposed speed of recession that the galaxies display. Using this system of "redshift" some galaxies are measured to be moving away from Earth at an unbelievable 90 percent of light-speed.
All that we see and experience is supposed to have been born in the Big Bang explosion, so the original inertia imparted to the Universe came from that preternatural event. Since the distances and the recessional velocities of objects are correlated with a time-scale, something like a galaxy or a quasi-stellar object (QSO) that is 10 billion light-years away is also thought to be as it was 10 billion years ago. Astronomers are seeing ancient light that has been traveling through space for 10 billion years before finally impinging on their detectors.
The current estimate for the age of the Universe is 13.7 billion years, based on data from powerful telescopes that are supposed to be capable of detecting galaxies that approach that distance from Earth. As mentioned, distance and time are thought to be related to each other because of redshift, so as far as we can see into the Universe provides information that determines how old we perceive it to be. In other words, the diameter of the observable Universe should be approximately 27.4 billion light-years.
There is a conundrum associated with that figure, however. According to a current press release, the Universe is thought to be 156 billion light-years in diameter and not 27.4 billion! How can this be? The answer, according to theoretical physicists, is inflation.
Astrophysicists of the recent past were dismayed when their observations seemed to indicate greater complexity in the early Universe than should exist. As the principle of inflation states, though, it is not merely the acceleration from the Big Bang that is affecting the spectra of remote galaxies and QSOs, but that the space in which they are embedded is expanding.
If it requires X amount of time for a galaxy to form and the Universe is Y years old, then a galaxy should not exist at time-distances less than Y minus X. When such formations were seen, as far as the relevant theories are concerned, some other explanatio
Dec 15, 2009
How big is the Universe? How old is it?
Today, cosmology is dominated by the Big Bang theory. The theory's major premise is that there was once a void containing no matter, no space, and no time. For some reason not explained by the scientists who support the theory, an irruption of energy from another realm of existence replaced the void with what eventually became the present Universe.
The Big Bang theory was postulated because the astronomer Edwin Hubble, using the 100-inch telescope at Mt. Wilson observatory, believed that he had observed remote galaxies receding from the Milky Way. The most surprising piece of his recorded data was not the recession itself, but the high velocities associated with his measurements. According to his calculations, some galaxies were traveling away from his observatory at thousands of kilometers per second.
Hubble arrived at his conclusion because of what was later to be called the "redshift" of light frequencies in spectrograms from his galactic images. Adapting the Doppler effect (named for the Austrian physicist Christian Doppler, who came up with the idea in 1842) to the spectra of various galaxies, Hubble thought that the change in location of particular elemental signatures called Fraunhofer lines (for the German physicist Joseph von Fraunhofer) indicated that the lightwaves had been shifted toward the red end of the spectrum by an apparent recessional velocity.
Fraunhofer lines are supposed to occur at specific frequencies identified in the spectrum by the kind of element that is absorbing the light. If they are in a different location, then they have been Doppler-shifted because of the element's acceleration. This forms the backbone of galactic-scale distance calculations and the supposed speed of recession that the galaxies display. Using this system of "redshift" some galaxies are measured to be moving away from Earth at an unbelievable 90 percent of light-speed.
All that we see and experience is supposed to have been born in the Big Bang explosion, so the original inertia imparted to the Universe came from that preternatural event. Since the distances and the recessional velocities of objects are correlated with a time-scale, something like a galaxy or a quasi-stellar object (QSO) that is 10 billion light-years away is also thought to be as it was 10 billion years ago. Astronomers are seeing ancient light that has been traveling through space for 10 billion years before finally impinging on their detectors.
The current estimate for the age of the Universe is 13.7 billion years, based on data from powerful telescopes that are supposed to be capable of detecting galaxies that approach that distance from Earth. As mentioned, distance and time are thought to be related to each other because of redshift, so as far as we can see into the Universe provides information that determines how old we perceive it to be. In other words, the diameter of the observable Universe should be approximately 27.4 billion light-years.
There is a conundrum associated with that figure, however. According to a current press release, the Universe is thought to be 156 billion light-years in diameter and not 27.4 billion! How can this be? The answer, according to theoretical physicists, is inflation.
Astrophysicists of the recent past were dismayed when their observations seemed to indicate greater complexity in the early Universe than should exist. As the principle of inflation states, though, it is not merely the acceleration from the Big Bang that is affecting the spectra of remote galaxies and QSOs, but that the space in which they are embedded is expanding.
If it requires X amount of time for a galaxy to form and the Universe is Y years old, then a galaxy should not exist at time-distances less than Y minus X. When such formations were seen, as far as the relevant theories are concerned, some other explanatio
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