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Puzzles and Progress

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  • Puzzles and Progress

    THE FABRIC of the COSMOS, Brian Greene, 2004
    ```(annotated and with added bold highlights by Epsilon=One)
    Chapter 10 - Deconstructing the Bang
    Puzzles and Progress
    With these discoveries, it thus seemed manifest that the pieces of the cosmological puzzle were falling into place. Questions left unanswered by the standard big bang theory — What ignited the outward swelling of space? Why is the temperature of the microwave background radiation so uniform? Why does space seem to have a flat shape? — were addressed by the inflationary theory. Even so, thorny issues regarding fundamental origins have continued to mount: Was there an era before the inflationary burst, and if so, what was it like? What introduced an inflaton field displaced from its lowest-energy configuration to initiate the inflationary expansion? And, the newest question of all, why is the universe apparently composed of such a mishmash of ingredients — 5 percent familiar matter, 25 percent dark matter, 70 percent dark energy? Despite the immensely pleasing fact that this cosmic recipe agrees with inflation's prediction that the universe should have 100 percent of the critical density, and although it simultaneously explains the accelerated expansion found by supernova studies, many physicists view the hodgepodge composition as distinctly unattractive. Why many have asked, has the universe's composition turned out to be so complicated? Why are there a handful of disparate ingredients in such seemingly random abundances? Is there some sensible underlying plan that theoretical studies have yet to reveal?

    No one has advanced any convincing answers to these questions; they are among the pressing research problems driving current cosmological research and they serve to remind us of the many tangled knots we must still unravel before we can claim to have fully understood the birth of the universe. But despite the significant challenges that remain, inflation is fari arid away the front-running cosmological theory. To be sure, physicists' belief in inflation is grounded in the achievements we've so far discussed. But the confidence in inflationary cosmology has roots that run deeper still. As we'll see in the next chapter, a number of other considerations — coming from both observational and theoretical discoveries — have convinced many physicists who work in the field that the inflationary framework is our generation's most important and most lasting contribution to cosmological science.
    Last edited by Reviewer; 10-06-2012, 05:06 PM.