March 17, 2005
CAN'T EXPLAIN IT, BUT I KNOW IT'S FINE-TUNED:
Misconceptions about the Big Bang: Baffled by the expansion of the universe? You're not alone. Even astronomers frequently get it wrong (Charles H. Lineweaver and Tamara M. Davis, 2/21/05, Scientific American)
Forty years ago this July, scientists announced the discovery of definitive evidence for the expansion of the universe from a hotter, denser, primordial state. They had found the cool afterglow of the big bang: the cosmic microwave background radiation. Since this discovery, the expansion and cooling of the universe has been the unifying theme of cosmology, much as Darwinian evolution is the unifying theme of biology. Like Darwinian evolution, cosmic expansion provides the context within which simple structures form and develop over time into complex structures. Without evolution and expansion, modern biology and cosmology make little sense.The expansion of the universe is like Darwinian evolution in another curious way: most scientists think they understand it, but few agree on what it really means. A century and a half after On the Origin of Species, biologists still debate the mechanisms and implications (though not the reality) of Darwinism, while much of the public still flounders in pre-Darwinian cluelessness. Similarly, 75 years after its initial discovery, the expansion of the universe is still widely misunderstood. A prominent cosmologist involved in the interpretation of the cosmic microwave background, James Peebles of Princeton University, wrote in 1993: "The full extent and richness of this picture [the hot big bang model] is not as well understood as I think it ought to be ... even among those making some of the most stimulating contributions to the flow of ideas."
Renowned physicists, authors of astronomy textbooks and prominent popularizers of science have made incorrect, misleading or easily misinterpreted statements about the expansion of the universe. Because expansion is the basis of the big bang model, these misunderstandings are fundamental.
Hard to keep everyone on the same page when you're just making stuff up. Posted by Orrin Judd at March 17, 2005 5:19 PM
Thanks, Orrin.
Posted by: Eugene S. at March 17, 2005 7:11 PMBut their faith is firm. Credit where due.
Posted by: ghostcat at March 17, 2005 7:14 PMIt occurs to me that if you assume that the "Big Bang" starts out larger than a point, the need for "inflation" and the homogeneity problems go away. Of course, then you are stuck explaining why a sphere (or some other shape?) of homogenous "stuff" just suddenly "happened".
Mr. Ortega;
Well, nothing's a point in the real world. There's a distance called the "planck-length" which is the smallest meaningful distance. Shorter than that, quantum effects are so dominant that length and position cease to be relevant.
But even if you start with some fixed, greated than planck-length size, you still have the homogenity problem in the original volume. It would also have to be a very large volume (basically as big as the Universe after inflation in current theories).
As for the people mocking the "faith" of the scientists - are you claiming that the background radition is a matter of opinion? Or is it a physical fact that one might be tempted to explain? What about the measured expansion of the Universe? I understand that there's an awful lot of handwaving going on in cosmology, but you speak of it as if the whole thing was invented ex nihilo, rather than in response to observed properties of reality.
Posted by: Annoying Old Guy at March 18, 2005 12:38 AM"Hard to keep everyone on the same page when you're just making stuff up."
That must be why there are so many religions.
Posted by: Robert Duquette at March 18, 2005 3:18 AMAOG:
Have you read the article? The problem is that they're making it up. Any grapefruit sized space containing the mass of a galaxy would be a black hole. A series of such overlapping regions (which the article discusses) would not be as homogeneous as the background radiation indicates. The "measured" expansion of the universe appears to be accelerating, which has no explanation in general relativity, but instead requires invoking some unvarified concepts from quantum mechanics which are not consistent (i.e., can not be unified) with the theory (i.e., General Relativity) which is used to describe the expansion.
"Just making stuff up" is called a hypothesis. There is nothing wrong with it. Scientists often come up with wild speculations after observations don't fit the previously established theories.
The fact that science now says things are true where before they did not think so, and that science in the future will point out errors in what we believe true today is not proof that science does not work, but proof that science does work.
The difference between science and religion is that the hypothesis must be tested.
Posted by: Chris Durnell at March 18, 2005 12:23 PMcd: religous hypothi are tested all the time; its called life. a badly formed religion will produce observably bad results in its adherents. what do you think the comparative results are between islam and christianity ? knowledge is a continuum; science and religion aren't in conflict, only the people who insist on being partisan about one side or the other.
Posted by: cjm at March 18, 2005 7:06 PM