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9 Billion-Year-Old "Dark Energy" Reported
loid_void writes to mention a New York Times article about the discovery that dark energy, or antigravity, was present at the formation of the universe. A team of 'dark energy prospectors' at the Space Telescope Science Institute theorizes that this may have directed the evolution of the cosmos. By observing supernova activity almost 8 billion years in the past, the team was able to study whether or not dark energy has changed over the millennia. From the article: "The data suggest that, in fact, dark energy has changed little, if at all, over the course of cosmic history. Though hardly conclusive, that finding lends more support to what has become the conventional theory, that the source of cosmic antigravity is the cosmological constant, a sort of fudge factor that Einstein inserted into his cosmological equations in 1917 to represent a cosmic repulsion embedded in space. Although Einstein later abandoned the cosmological constant, calling it a blunder, it would not go away. It is the one theorized form of dark energy that does not change with time. Sean Carroll, a cosmologist at the California Institute of Technology who was not on the team, said: 'Had they found the evolution was not constant, that would have been an incredibly earthshaking discovery. They looked where no one had been able to look before.'"
Sean Carroll (and some other notable physicists) have a blog which covered this in more detail. See http://cosmicvariance.com/2006/11/16/dark-energy-h as-long-been-dark-energy-like/
He provides a great explanation for the reader without familiarity with advanced physics, but at a level which is still interesting to the technical reader.
Honestly, there are real alternatives to the big bang theory. One of them is the idea that our "universe" is at the center of a black hole, which effectively places the same limits (you can't get out, and neither can light) on the boundary.
5 4.pdfk s/Rudmin/POSTER0H.PDF
If that's the case, the "big bang" turns into the initial collapse; and the "dark energy" that drives expansion becomes the space-energy expansion inside the schwarzschild radius that is needed for conservation of energy.
I have a relative who is working on some of this...
http://absimage.aps.org/image/MWS_SES06-2006-0000
http://physics.fau.edu/Events/Gulf_Coast_2006/Tal