Friday, January 18, 2013

Cosmic Inflation

By Julie Rahm 
One of my favorite television shows is the “Big Bang Theory.” The show features four young men and their lives as research physicists. I enjoy the show because, in school, I majored in physics. I attended classes with these personality types and I find their characters entertainingly (and perhaps personally) familiar.  Dating physicists is not for the meek! Anyway, there is not a lot wrong with the Big Bang Theory television show. It is well done. However, there is something wrong with the creation of the universe Big Bang theory.
The Big Bang theory is the prevailing cosmological model that describes the early development of the Universe. According to the theory, the Universe was once in an extremely hot and dense state, which expanded rapidly. This rapid expansion caused the Universe to cool and resulted in its present continuously expanding state. According to the most recent measurements and observations, the Big Bang occurred approximately 13.75 billion years ago, which is thus considered the age of the Universe. After its initial expansion, the Universe cooled sufficiently to allow energy to be converted into various subatomic particles, including protons, neutrons, and electrons. That’s the Big Bang theory in a nutshell.
While the Big Bang theory successfully explains the cosmic microwave background radiation and the origin of the light elements, it has three significant problems.
The Flatness Problem: The Wilkinson Microwave Anisotropy Probe (WMAP) was a NASA Explorer mission that launched in June 2001 to make fundamental measurements of cosmology. WMAP has determined the geometry of the universe is nearly flat. However, under Big Bang cosmology, curvature grows with time. A universe as flat as we see it today would require an extreme fine-tuning of conditions in the past, which would be an unbelievable coincidence.
The Horizon Problem: Distant regions of space in opposite directions of the sky are so far apart that, assuming standard Big Bang expansion, they could never have been in contact with each other. This is because the light travel time between them exceeds the age of the universe. Yet the uniformity of the cosmic microwave background temperature tells us that these regions must have been in contact with each other in the past.
The Monopole Problem: Big Bang cosmology predicts that a very large number of heavy, stable "magnetic monopoles" should have been produced in the early universe. However, magnetic monopoles have never been observed, so if they exist at all, they are much more rare than the Big Bang theory predicts.
To reconcile the Big Bang problems, Inflation Theory developed by Alan Guth, Andrei Linde, Paul Steinhardt, and Andy Albrecht offers solutions. It proposes a period of extremely rapid (exponential) expansion of the universe prior to the more gradual Big Bang expansion. Inflation is now considered an extension of the Big Bang theory since it explains the above puzzles so well, while retaining the basic paradigm of a homogeneous expanding universe. So, now you know!
To keep your personal universe expanding, visit my website at 

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