The Big Bang
The Big Bang theory states that the universe arose from a singularity of virtually no size, which gave rise to the dimensions of space and time, in addition to all matter and energy. At the beginning of the Big Bang, the four fundamental forces began to separate from each other. Early in its history (10-36 to 10-32 seconds), the universe underwent a period of short, but dramatic, hyper-inflationary expansion. The cause of this inflation is unknown, but was required for life to be possible in the universe.
Quarks and antiquarks combined to annihilate each other. Originally, it was expected that the ratio of quarks and antiquarks to be exactly equal to one, since neither would be expected to have been produced in preference to the other. If the ratio were exactly equal to one, the universe would have consisted solely of energy - not very conducive to the existence of life. However, recent research showed that the charge–parity violation could have resulted naturally given the three known masses of quark families.1 However, this just pushes fine tuning a level down to ask why quarks display the masses they have. Those masses must be fine tuned in order to achieve a universe that contains any matter at all.
Large, just right-sized universe
Even so, the universe is enormous compared to the size of our Solar System. Isn't the immense size of the universe evidence that humans are really insignificant, contradicting the idea that a God concerned with humanity created the universe? It turns out that the universe could not have been much smaller than it is in order for nuclear fusion to have occurred during the first 3 minutes after the Big Bang. Without this brief period of nucleosynthesis, the early universe would have consisted entirely of hydrogen.2 Likewise, the universe could not have been much larger than it is, or life would not have been possible. If the universe were just one part in 1059 larger,3 the universe would have collapsed before life was possible. Since there are only 1080 baryons in the universe, this means that an addition of just 1021 baryons (about the mass of a grain of sand) would have made life impossible. The universe is exactly the size it must be for life to exist at all.
Early evolution of the universe
Cosmologists assume that the universe could have evolved in any of a number of ways, and that the process is entirely random. Based upon this assumption, nearly all possible universes would consist solely of thermal radiation (no matter). Of the tiny subset of universes that would contain matter, a small subset would be similar to ours. A very small subset of those would have originated through inflationary conditions. Therefore, universes that are conducive to life "are almost always created by fluctuations into the[se] 'miraculous' states," according to atheist cosmologist Dr. L. Dyson.4
Just right laws of physics
The laws of physics must have values very close to those observed or the universe does not work "well enough" to support life. What happens when we vary the constants? The strong nuclear force (which holds atoms together) has a value such that when the two hydrogen atoms fuse, 0.7% of the mass is converted into energy. If the value were 0.6% then a proton could not bond to a neutron, and the universe would consist only of hydrogen. If the value were 0.8%, then fusion would happen so readily that no hydrogen would have survived from the Big Bang. Other constants must be fine-tuned to an even more stringent degree. The cosmic microwave background varies by one part in 100,000. If this factor were slightly smaller, the universe would exist only as a collection of diffuse gas, since no stars or galaxies could ever form. If this factor were slightly larger, the universe would consist solely of large black holes. Likewise, the ratio of electrons to protons cannot vary by more than 1 part in 1037 or else electromagnetic interactions would prevent chemical reactions. In addition, if the ratio of the electromagnetic force constant to the gravitational constant were greater by more than 1 part in 1040, then electromagnetism would dominate gravity, preventing the formation of stars and galaxies. If the expansion rate of universe were 1 part in 1055 less than what it is, then the universe would have already collapsed. The most recently discovered physical law, the cosmological constant or dark energy, is the closest to zero of all the physical constants. In fact, a change of only 1 part in 10120 would completely negate the effect.
Universal probability bounds
"Unlikely things happen all the time." This is the mantra of the anti-design movement. However, there is an absolute physical limit for improbable events to happen in our universe. The universe contains only 1080 baryons and has only been around for 13.7 billion years (1018 sec). Since the smallest unit of time is Planck time (10-45 sec),5 the lowest probability event that can ever happen in the history of the universe is:
1080 x 1018 x 1045 =10143
So, although it would be possible that one or two constants might require unusual fine-tuning by chance, it would be virtually impossible that all of them would require such fine-tuning. Some physicists have indicated that any of a number of different physical laws would be compatible with our present universe. However, it is not just the current state of the universe that must be compatible with the physical laws. Even more stringent are the initial conditions of the universe, since even minor deviations would have completely disrupted the process. For example, adding a grain of sand to the weight of the universe now would have no effect. However, adding even this small amount of weight at the beginning of the universe would have resulted in its collapse early in its history.
What do cosmologists say?
Even though many atheists would like to dismiss such evidence of design, cosmologists know better, and have made statements such as the following, which reveal the depth of the problem for the atheistic worldview:
*"This type of universe, however, seems to require a degree of fine-tuning of the initial conditions that is in apparent conflict with 'common wisdom'."6
*"Polarization is predicted. It's been detected and it's in line with theoretical predictions. We're stuck with this preposterous universe."7
*"In all of these worlds statistically miraculous (but not impossible) events would be necessary to assemble and preserve the fragile nuclei that would ordinarily be destroyed by the higher temperatures. However, although each of the corresponding histories is extremely unlikely, there are so many more of them than those that evolve without "miracles," that they would vastly dominate the livable universes that would be created by Poincare recurrences. We are forced to conclude that in a recurrent world like de Sitter space our universe would be extraordinarily unlikely."8