Post by 1dave on Nov 20, 2020 8:40:28 GMT -7
Olbers' paradox - Main article: Olbers' paradox
The expansion of space summarized by the Big Bang interpretation of Hubble's law is relevant to the old conundrum known as Olbers' paradox: If the universe were infinite in size, static, and filled with a uniform distribution of stars, then every line of sight in the sky would end on a star, and the sky would be as bright as the surface of a star. However, the night sky is largely dark.[43][44]
Since the 17th century, astronomers and other thinkers have proposed many possible ways to resolve this paradox, but the currently accepted resolution depends in part on the Big Bang theory, and in part on the Hubble expansion: In a universe that exists for a finite amount of time, only the light of a finite number of stars has had enough time to reach us, and the paradox is resolved. Additionally, in an expanding universe, distant objects recede from us, which causes the light emanated from them to be redshifted and diminished in brightness by the time we see it.[43][44]
In 1919 Edwin Hubble arrived at Mount Wilson Observatory, California with the completion of the 100-inch (2.5 m) Hooker Telescope, then the world's largest.
At that time, the prevailing view of the cosmos was that the universe consisted entirely of the Milky Way Galaxy.
Using the Hooker Telescope at Mount Wilson, Hubble identified Cepheid variables (a kind of star that is used as a means to determine the distance from the galaxy in several spiral nebulae, including the Andromeda Nebula and Triangulum. His observations, made in 1924, proved conclusively that these nebulae were much too distant to be part of the Milky Way and were, in fact, entire galaxies outside our own. Despite the opposition, Hubble, then a thirty-five-year-old scientist, had his findings first published in The New York Times on November 23, 1924, then presented them to other astronomers at the January 1, 1925 meeting of the American Astronomical Society.
Hubble's findings fundamentally changed the scientific view of the universe.
In 1927, two years before Hubble published his own article, the Belgian priest and astronomer Georges Lemaître was the first to publish research deriving what is now known as Hubble's law. According to the Canadian astronomer Sidney van den Bergh, "the 1927 discovery of the expansion of the universe by Lemaître was published.
Hubble's law, also known as the Hubble–Lemaître law, is the observation in physical cosmology that galaxies are moving away from Earth at speeds proportional to their distance. In other words, the farther they are the faster they are moving away from Earth. The velocity of the galaxies has been determined by their redshift, a shift of the light they emit toward the red end of the visible spectrum.
In December 1941, Hubble reported to the American Association for the Advancement of Science that results from a six-year survey with the Mt. Wilson telescope did not support the expanding universe theory. According to a Los Angeles Times article reporting on Hubble's remarks, "The nebulae could not be uniformly distributed, as the telescope shows they are, and still fit the explosion idea. Explanations which try to get around what the great telescope sees, he said, fail to stand up. The explosion, for example, would have had to start long after the earth was created, and possibly even after the first life appeared here."[40][41] (Hubble's estimate of what we now call the Hubble constant would put the Big Bang only 2 billion years ago.)
Sir Fred Hoyle (24 June 1915 – 20 August 2001) was an English astronomer who formulated the theory of stellar nucleosynthesis. in 1948 he began to argue for the universe as being in a "steady state" and formulated the steady state theory. He coined the term "Big Bang" on BBC radio's Third Program broadcast on 28 March 1949 to challenge what has become the prevailing theory.
en.wikipedia.org/wiki/Big_Bang
The Big Bang theory is the prevailing cosmological model for the universe[1] from the earliest known periods through its subsequent large-scale evolution.[2][3][4] The model describes how the universe expanded from a very high-density and high-temperature state,[5][6] and offers a comprehensive explanation for a broad range of phenomena, including the abundance of light elements, the cosmic microwave background (CMB), large scale structure and Hubble's law.[7]
If the known laws of physics are extrapolated to the highest density regime, the result is a singularity which is typically associated with the Big Bang. Physicists are undecided whether this means the universe began from a singularity, or that current knowledge is insufficient to describe the universe at that time. Detailed measurements of the expansion rate of the universe place the Big Bang at around 13.8 billion years ago, which is thus considered the age of the universe.[8]
The Big Bang theory is the prevailing cosmological model for the universe[1] from the earliest known periods through its subsequent large-scale evolution.[2][3][4] The model describes how the universe expanded from a very high-density and high-temperature state,[5][6] and offers a comprehensive explanation for a broad range of phenomena, including the abundance of light elements, the cosmic microwave background (CMB), large scale structure and Hubble's law.[7]
If the known laws of physics are extrapolated to the highest density regime, the result is a singularity which is typically associated with the Big Bang. Physicists are undecided whether this means the universe began from a singularity, or that current knowledge is insufficient to describe the universe at that time. Detailed measurements of the expansion rate of the universe place the Big Bang at around 13.8 billion years ago, which is thus considered the age of the universe.[8]
The idea that everything came from nothing was unacceptable to me. On learning of "black holes," in 1965 I postulated that our "Big Bang" was the opening of a singularity or black hole in a previous universe.
There was time before our universe began and We are Living in a Black Hole!
en.wikipedia.org/wiki/Big_Bang
A gravitational singularity or spacetime singularity is a location in spacetime where the gravitational field of a celestial body becomes infinite in a way that does not depend on the coordinate system. The quantities used to measure gravitational field strength are the scalar invariant curvatures of spacetime, which includes a measure of the density of matter. Since such quantities become infinite within the singularity, the laws of normal spacetime cannot exist.[1][2]
Gravitational singularities are mainly considered within general relativity, where density apparently becomes infinite at the center of a black hole, and within astrophysics and cosmology as the earliest state of the universe during the Big Bang. Physicists are undecided whether the prediction of singularities means that they actually exist (or existed at the start of the Big Bang), or that current knowledge is insufficient to describe what happens at such extreme densities.
A gravitational singularity or spacetime singularity is a location in spacetime where the gravitational field of a celestial body becomes infinite in a way that does not depend on the coordinate system. The quantities used to measure gravitational field strength are the scalar invariant curvatures of spacetime, which includes a measure of the density of matter. Since such quantities become infinite within the singularity, the laws of normal spacetime cannot exist.[1][2]
Gravitational singularities are mainly considered within general relativity, where density apparently becomes infinite at the center of a black hole, and within astrophysics and cosmology as the earliest state of the universe during the Big Bang. Physicists are undecided whether the prediction of singularities means that they actually exist (or existed at the start of the Big Bang), or that current knowledge is insufficient to describe what happens at such extreme densities.
Now the argument is whether our universe will begin to collapse, or expand forever and dilute into nothing.
I submit that IMO each galaxy came into ours as it's black hole was sucked into ours and testifies that the previous universe ended up in a big crunch - as will ours.
