Posted on 04/25/2002 2:34:20 PM PDT by Bloody Sam Roberts
How did the universe begin, and how will it end? Among cosmologists, the mainstream belief is that the universe began with a bang billions of years ago, and will fizzle out billions of years from now. But two theorists have just fired their latest volley at that belief, saying there could be a timeless cycle of expansion and contraction. Its an idea as old as Hinduism, updated for the 21st century.
THE CYCLIC MODEL, developed by Princeton Universitys Paul Steinhardt and Cambridge Universitys Neil Turok, made its highest-profile appearance yet Thursday on Science Express, the Web site for the journal Science. But past incarnations of the idea have been hotly debated within the cosmological community for the past year and Steinhardt acknowledges that he has an uphill battle on his hands.
It will take people a while to get used to it, he told MSNBC.com. This introduces a number of concepts that are quite unfamiliar, even to a cosmologist.
TINKERING WITH THE COSMOS
Years ago, Steinhardt played a prominent role in formulating what is now the most widely accepted scientific picture of the universes beginnings, known as inflationary Big Bang theory: that a vanishingly small quantum fluctuation gave rise in an instant to an inflated region of space-time, kicking off an expansion that is now picking up speed.
The model has weathered repeated experimental tests, including studies of patterns in the microwave afterglow of the Big Bang.
All the competing models were knocked off, Steinhardt said. So we had a situation where it looked as if we had converged on a single idea. But I was always disturbed by the idea that there were no competitors around.
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Time does not exist for mathematics. That "meaning" is imposed upon the mathematical construct.
Intriguing thought! I'm curious...If inflationary cosmology proves correct, then do you think that it might explain ANOMALOUS GRAVITATIONAL FORCE?
A discussion of this phenomenon appears in the 4 October 1999 issue of Newsweek magazine (See also the December 1998 issue of Scientific American.) The mystery of the tiny unexplained acceleration towards the sun in the motion of the Pioneer 10, Pioneer 11 and Ulysses spacecraft remains unexplained. A team of planetary scientists and physicists led by John Anderson (Pioneer 10 Principal Investigator for Celestial Mechanics) has identified a tiny unexplained acceleration towards the sun in the motion of the Pioneer 10, Pioneer 11, and Ulysses spacecraft. The anomalous acceleration - about 10 billion times smaller than the acceleration we feel from Earth's gravitational pull - was identified after detailed analyses of radio data from the spacecraft. A variety of possible causes were considered including: perturbations from the gravitational attraction of planets and smaller bodies in the solar system; radiation pressure, the tiny transfer of momentum when photons impact the spacecraft; general relativity; interactions between the solar wind and the spacecraft; possible corruption to the radio Doppler data; wobbles and other changes in Earth's rotation; outgassing or thermal radiation from the spacecraft; and the possible influence of non-ordinary or dark matter. After exhausting the list of explanations deemed most plausible, the researchers examined possible modification to the force of gravity as explained by Newton's law with the sun being the dominant gravitational force. "Clearly, more analysis, observation, and theoretical work are called for," the researchers concluded. The scientists expect the explanation when found will involve conventional physics.
No, it definitely does not. (I think that the explanation there has to do with good old-fashioned electromagnetism.) Inflation is a runaway process, and it requires a stable high vacuum energy state called a "false vacuum" that does not exist in today's universe.
I've posted the following on several threads, usually when the question comes up, "what happened before the big bang". I hope it helps a bit.
The question, "what happened before Archduke Ferdinand was shot" is a well-formed question, as is, "what is south of Topeka, Kansas." The question, "what happened before the big bang" is an ill-formed question, as is, "what lies south of the south pole."
Imagine you are travelling south, down to the south pole. As you get closer to the pole, the east-west direction does a curious thing: it curls back upon itself in an ever-tightening circle, disappearing completely as you reach the point of the pole itself. At that place, the ground is as smoothly two-dimensional as anywhere else on Earth, but every possible direction points north, even directions that lie at right angles to each other.
Imagine that you can go backwards in time, back to the big bang. As you get closer to the big bang, space does a curious thing: the spatial dimensions curl back upon themselves in an ever-tightening circle, disappearing completely as you reach the singularity itself. At that event, spacetime is as smoothly four-dimensional as at any other event in history, but every possible direction points towards the future, even directions that lie at right angles to each other.
I stress that what I have laid before you is not an analogy, but two separate examples of the same phenomenon.
There may exist events that are external to the space and time dimensions of our universe, but none of them can be said to come before or after any events of our universe; they cannot be included in any causal framework such as history. Time itself is strictly internal to our universe. If we want to use words like "cause" and "before", we must needs keep our game pieces on the board.
Okay make your perpetual motion machine.
So... "Once upon a time, there was nothing...
... then it EXPLODED!!!"
So that you can exist and ask the questions.
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