steadystate
Registered Member
Here is an excerpt from: http://www-cfa.harvard.edu/seuforum/explore/bigbang/bigbang.htm
SteadyState
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DID THE UNIVERSE HAVE A BEGINNING?
The ancient stories of many cultures describe a universe that was created. Other cultures speak of a universe that always existed. St. Augustine wondered, "How can there be a time when there was no time?" Was time created along with the universe? Medieval scholars reasoned that the universe MUST have been created a finite time ago: For if the universe were infinitely old, an INFINITE amount of time would have had to pass to get to our own present day, and so, they reasoned, the universe could never get to the present!
Contrary to popular belief, the Big Bang scenario is NOT a theory of the origin of the universe. In fact, it is completely silent about how space, time, and energy came into existence. Even Einstein, in his early essays, spoke of the "origin of the expansion," not the origin of the universe.
What Do We Need to Know?
There are many theories of what might have preceded the Big Bang. Perhaps the most important of these is a theory called the "inflationary universe," created in 1980 by the physicist Alan Guth, and developed by many other scientists since then.
The inflationary scenario builds on the Big Bang, but raises the possibility that space and time existed long before the Big Bang. In fact, the theory has led to possibility that our own observable universe was spawned by a much larger, older "mother" universe.
Of course, that would only extend the question back in time: How did the "mother" universe come into existence? But inflation raises, for the first time, the possibility that the universe always existed. (In the works: A Forum pop-up tutorial explores the "inflationary universe" scenario.)
What's the Best Current "Answer"?
It is likely that the universe existed before the Big Bang, and possible that the universe has always existed. That tentative conclusion is based on two things:
First, the inflationary scenario is the best current theory of the universe, in that it can describe all the current observations of the structure of the universe. It has met four critical observational tests, which will be described further at this Forum site.
Second, in the last few years it has appeared that the "mother" universe seems to be an inevitable feature of inflationary theories -- that is, different versions of the inflationary scenario still predict that space and time existed before the Big Bang.
However, the inflationary universe theory is still controversial, because key parts of the theory have not yet been able to be tested by experiment or observation.
What are Scientists Looking For?
A very exciting forthcoming space mission will help to test the inflationary universe scenario. Called the Microwave Anisotropy Probe, it is designed to look in exquisite detail at the faint light left over from the Big Bang. This light contains subtle patterns that are a clue to what happened during the earliest moments of our universe, and possibly even before. The results from the mission will help us choose between competing theories, and possibly even help answer the question, Did the universe have a beginning?
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I'm becoming more enlightened about current ideas about the universe.
SteadyState
SteadyState
---------------------------------------------
DID THE UNIVERSE HAVE A BEGINNING?
The ancient stories of many cultures describe a universe that was created. Other cultures speak of a universe that always existed. St. Augustine wondered, "How can there be a time when there was no time?" Was time created along with the universe? Medieval scholars reasoned that the universe MUST have been created a finite time ago: For if the universe were infinitely old, an INFINITE amount of time would have had to pass to get to our own present day, and so, they reasoned, the universe could never get to the present!
Contrary to popular belief, the Big Bang scenario is NOT a theory of the origin of the universe. In fact, it is completely silent about how space, time, and energy came into existence. Even Einstein, in his early essays, spoke of the "origin of the expansion," not the origin of the universe.
What Do We Need to Know?
There are many theories of what might have preceded the Big Bang. Perhaps the most important of these is a theory called the "inflationary universe," created in 1980 by the physicist Alan Guth, and developed by many other scientists since then.
The inflationary scenario builds on the Big Bang, but raises the possibility that space and time existed long before the Big Bang. In fact, the theory has led to possibility that our own observable universe was spawned by a much larger, older "mother" universe.
Of course, that would only extend the question back in time: How did the "mother" universe come into existence? But inflation raises, for the first time, the possibility that the universe always existed. (In the works: A Forum pop-up tutorial explores the "inflationary universe" scenario.)
What's the Best Current "Answer"?
It is likely that the universe existed before the Big Bang, and possible that the universe has always existed. That tentative conclusion is based on two things:
First, the inflationary scenario is the best current theory of the universe, in that it can describe all the current observations of the structure of the universe. It has met four critical observational tests, which will be described further at this Forum site.
Second, in the last few years it has appeared that the "mother" universe seems to be an inevitable feature of inflationary theories -- that is, different versions of the inflationary scenario still predict that space and time existed before the Big Bang.
However, the inflationary universe theory is still controversial, because key parts of the theory have not yet been able to be tested by experiment or observation.
What are Scientists Looking For?
A very exciting forthcoming space mission will help to test the inflationary universe scenario. Called the Microwave Anisotropy Probe, it is designed to look in exquisite detail at the faint light left over from the Big Bang. This light contains subtle patterns that are a clue to what happened during the earliest moments of our universe, and possibly even before. The results from the mission will help us choose between competing theories, and possibly even help answer the question, Did the universe have a beginning?
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I'm becoming more enlightened about current ideas about the universe.
SteadyState
