Curvity and Guth's Inflation
Alan Guth wrote a book called "The Inflationary Universe" about a theory called "Inflation" discovered by Alan Guth in 1979. Up until that time a number of problems existed with the Big Bang theory that had yet to be solved.
One of them was called the "Horizon problem" which is related to the uniformity of the observed universe - How can the large-scale universe look the same in all directions if the universe formed over a finite period of time? The problem was put in more exact terms when the cosmic microwave background (CMB) radiation was discovered and it showed that the background temperature of the universe was the same in all directions to an accuracy of one part in 100,000. But if everything started in one Big Bang that happened 14 billion years ago, then how can two sources of radiation that are now 28 billion light years apart in opposite directions in our sky have almost the exact same temperature? In other words, given that radiation cannot travel faster then the speed of light, there was no way for the background temperature in one part of our sky to equal that in another because they could not interact.
Dr. Guth's insight was to suggest that in the initial phases of the Big Bang, there existed a period much shorter then a second during which everything expanded from the very small to the very large at an exponential rate. That period called "Inflation" was then able to solve the "Horizon problem" because during the exponential expansion, any disturbances that existed previously would have been completely stretched out. A simple analogy is to take a cloth with a large number of many colored pockadots which is infinitely elastic and stretch it to the width and breath of the universe. If you then looked at the cloth, you would find that all you could see was one very small part of one pockadot. From your perspective in the middle on the stretched pockadot, all you would see in any direction is more of the same pockadot, all one color.
What makes Inflation theory astonishing, is that to explain what caused the exponential expansion, Guth says it was caused by "a strong gravitational repulsion" and that the gravitational repulsion is "identical to the effect of Einstein's cosmological constant" . Guth points out that the source of this "repulsive gravity" is a "false vacuum" which is "an ephemeral state that exerts its influence for only a brief moment in the early history of the universe."  quite unlike the cosmological constant.
However, from Daniel's chapter of gravity, Alan says
"Some of your cosmic theorists have proposed that at one time all of the matter in the Universe was contained in a single tremendous star or 'atom'. For some reason, which is not given, this atom exploded hurling outward the matter, which has become the star clusters and imparting to them the motion which we now observe several billions of years later."
And then goes on to say:
Through the concept of the curvature of physical law, however we see that the addition of mass to an existing body does not, necessarily increase the force of attraction between its parts, but may, under certain conditions, cause the field to become negative and the attraction to become a repulsion. ... This also explains why matter, although rather evenly distributed throughout the known Universe, is not distributed uniformly but is found in quite similar concentrations at comparatively regular distances.
In other words, the physics in Daniel's books, Curvity, had suggested that negative gravity could solve the Horizon problem 30 years before Inflation. What Dr. Alan Guth's Inflation theory does is show how negative gravity solves the problem. Another interesting point about Inflation is that the source of the negative gravity, the "GUT" theories are still being worked on.
If Curvity is true, then physics should be converging on it and Inflation certainly suggests that possibility.
- "The Inflationary Universe: The Quest for a New Theory of Cosmic Origins", Alan Guth, Perseus Books Group, 1998
- Page 173