THE BIG BANG / INFLATIONARY THEORY
The “Big Bang” is a misnomer. First of all, there was no Bang, or classical explosion of any sort. And there was no center point where it all originated. The universe created space and time when it came into being and so it arose “everywhere at once”.
The “Big Bang” is the name of the theory but does not actually describe the moment the universe came into existence. That moment is called, appropriately, creation. In creation, something comes out of nothing. And that is what seems to have happened.
About 13.8 billion years ago our universe was created by a successful bubble in spacetime which expanded rapidly and cooled into the present day universe.
The period of inflation happened about 10-35 seconds after the creation of the universe. At that time the universe was the size of a grape, but in about 10-32 seconds it expanded by a factor of 1050.
The inflation happened because temperatures dropped to the point where the strong nuclear force broke away from the weak and electromagnetic forces that it was unified with. This decoupling filled the tiny universe with a kind of energy called the vacuum energy, and as a consequence gravitation effectively became repulsive for a moment.
EVIDENCE:
1) Galaxies and quasars show redshifts, showing that they are receding due to
universal expansion. The expansion of space causes the redshift - not the
speed of the galaxies!
2) Matter (stars, galaxies, etc.) seems to have a maximum age of 13.8 billion years.
The most recent estimates for the age of the universe come from the WMAP and
Planck spacecraft (2012, 2013). The farthest detectable galaxy (January, 2014)
is Z8 GND 5296, with a redshift of 7.51, giving it an age of about 700 million
years shy of the universe’s age.
3) Microwave background radiation uniformly fills the universe. This is the remnant
radiation released at the time matter and energy decoupled. It has red-shifted
from heat and light into microwaves. The temperature of the radiation is 2.725
(about -270oC, three degrees above absolute zero).
3) continued: Verified by the Planck and WMAP space telescopes, this radiation
perfectly fits a blackbody curve. The data below from WMAP shows an excellent
agreement of actual observations (points) to theory predictions (orange curve).
4) The current "bubble and void" structure of the universe can be predicted from
this theory. Inflation would have made the early universe “lumpy” and this is
exactly how it appears from Planck and WMAP maps. (WMAP data shown below).
5) This theory predicts that the universe should be exactly flat, with a critical
density = 1. Current observational evidence supports this. Data from WMAP show
the universe’s shape within 0.4% of exactly flat. The most recent findings
(January 2014)come from the BOSS (Baryon Oscillation Spectroscopic Survey)
project in New Mexico. BOSS measured 1.2 million galaxies out to a distance of
490 million light years, creating a map of the nearby universe that is 99%
accurate. Their map suggeststhat the universe perfectly flat, and will continue
to expand forever, making the universe infinite in size. Whoa.
THE BIGGEST PROBLEM:
This combined theory relies on the universe being much more massive than we can now detect. Using this figure, we can "see" only 4.9% of the universe; we can infer another 26.8% in the form of dark matter, but 68.3% of the universe is still MISSING. (2013 data from Planck Space Telescope). This large quantity is accounted for in the form of dark energy.
“Dark energy” may be interpreted as a sort of “antigravity” repulsive force. (But cosmologists will tell you it is NOT a force.) If something in the universe is counteracting gravity, then there does not need to be as much matter (mass) factored into calculations for the Big Bang/ Inflationary models.
Einstein first proposed that there was something like this in 1917. He called it the cosmological constant, but later recanted it, calling it his “greatest blunder”. Maybe he was right all along. Most recent studies are pointing to this answer.