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This discussion is a
continuation from here, where is was off-topic.
In the 1990’s two teams announced the results of their investigations that had for aspiration to determine the deceleration parameter, the density parameter omega, and its relation to the geometry of the universe (the ratio of energy density to critical density).
The Supernova Cosmology Project, led by astronomer Saul Perlmutter (et al) of Lawrence Berkeley National Laboratory in California, and the High-z Supernova Search Team headed by Brian Schmidt (et al) of Australia National University, Siding Springs Observatories and Mount Stromolo in Australia, and Robert Kirshner (et al) of Harvard-Smithsonian Center for Astrophysics, studied distant supernovae SNe type Ia in an attempt to determine the value of omega (the ratio of the energy density of the universe to the critical density).
With the help of Hubble Space Telescope (HST) they were able to pin down the locations of supernovae Type Ia that exploded some four to seven billion light-years ago. The outcome of the investigation came as a shock (to say the least) to both teams, and detonated an implosion that shook the rest of the scientific community—within which the unity was already questionable. The 1998 SNe Ia observational data took those fissures and blew them apart, creating a situation of semi-mayhem (exemplified by the media clippings below) with alarming consequences:
Distant supernovae and their host galaxies appear to be receding slower than permitted by Hubble’s Law (the proportionality between redshift and distance). Remarkably, the observations are consistent with an accelerating expansion of the cosmos.
Quote:
Cosmologists Ponder Missing Energy “Cosmologists gather at Fermi National Laboratory in effort to explain compelling new evidence that the universe is expanding at an accelerating rate and to understand what appears to be an unknown form of energy associated with vacuum of space, the so-called ‘missing energy’ of the universe; if both current theory and new observations are correct, this energy must be acting as repulsive force to counteract gravity’s restraining influence and thus speed up cosmic expansion” (New York Times, May 5, 1998 Sec: F Science Desk p. 1). Wary Astronomers Ponder An Accelerating Universe (New York Times, March 3, 1998 Sec: F Science Desk p. 1)
Revolution in Cosmology …something is amiss. At the very least, the expansion is not decelerating as rapidly as once though. Either scientists must reconcile themselves to kooky energy, or they must modify or abandon inflation. (Scientific American, Jan. 1999 Vol. 280, 1
Accelerating the Cosmos “The cosmological constant, also called lambda...is a uniform, background energy permeating all of space. This energy gives space itself a sort of springiness, counteracting gravity on large scales…It came as a shock…the universe appeared to contain twice as much energy in the cosmological constant as it did in matter. POW…Thunderstruck astronomers…particle physicists are studying the structure of space to determine just what lambda might be…funny energy…gravity that bends space…slightly illicit…cosmological constant was mentioned as a possible culprit, but that reasoning still seemed to strange to take seriously…a huge cosmological constant…some form of energy we don’t understand…weird, fluid-like substance called quintessence, a squishy possibility…“This led me to reconsider my theoretical prejudices. I now think it is very reasonable that there should be a cosmological constant” [the latter is a quote from S. Hawking] (Astronomy, Oct. 1999 Vol. 27, 10, p. 44-51)
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It was thought that the SNe survey might pin-down the Hubble constant and carve order out of the general chaos. Now, unintuitively, we have a situation where not only are galaxies undecelerated but the galaxies appear to be accelerated—faster and faster as the radius of the universe tends toward infinity.
Light curves from distant supernovae were raising the peculiar specter that Einstein’s cosmological constant was real. The observations had then to be interpreted in such a way that they would not viscerally oppose the finely tuned expansion of inflation. The possibility that the new greatest blunder might revive some of the anti-big-bang rhetoric of the early 1950's loomed. That is to say, confronted with choice of reintroducing the fudge factor or sacking eight decades of theoretical cosmology, physicists had to scramble fast, and scramble fast they did.
This thread is designed to study the implications of the latest data and differing interpretations of the evidence.
CC
