A few of the key questions about big bang cosmology


  1. How is big bang cosmology (and base-2 natural inflation) consistent with General Relativity?
  2. How does big bang cosmology (and base-2) explain the Hubble expansion of the Universe?
  3. How can big bang cosmology (and base-2 natural inflation) explain the abundances of the light elements?
  4. How does big bang cosmology (and base-2 natural inflation) explain CMBR, the existence and properties of the cosmic microwave background radiation?
  5. How does big bang cosmology (and base-2 natural inflation) account for what is called the horizon problem whereby photons are roughly the same temperature —  2.725 degrees Kelvin — wherever you look in the universe?
  6. How does big bang cosmology (and base-2 natural inflation) account for what is called Flatness Problem? Almost all the evidence collected by cosmologists indicates that the Universe is flat. Like a sheet of paper on a desk, spacetime shows almost no curvature whatsoever.
  7. What about the magnetic monopole? All magnets have two poles, a north and a south. Even when a magnet is snapped in half the two poles remain. But this particle would effectively be a magnet with only one pole: a magnetic monopole!
  8. Why does the universe have more matter than antimatter?[98]


  1. Joseph Silk: Dark matter is here to stay but what is it? Should we change our theory if we fail to detect dark matter within a decade, or two?
  2. Eric Lerner: The density predictions made on the basis of the abundance of deuterium, lithium-7 and helium-4 are in contradiction with each other, and these predictions have grown worse with each new observation. The chance that the theory is right is now less than one in one hundred trillion.  (1991)
  3. Paul Halpern (The Big Bang’s Identity Crisis, PBS-TV, Fri, 30 May 2014): The discovery of the CMB was a victory for the Big Bang theory, yet it also presented a puzzle: The radiation was strikingly uniform across the sky. While later studies identified tiny variations of less than one part in 10,000, the standard Big Bang model couldn’t justify such uniformity. There simply wasn’t enough time in early cosmic history, when the universe was small, for energy to have traveled across space and evened out its temperature.Enter the brilliant concept of inflation, proposed in 1981 by Alan Guth, and later modified by Andrei Linde, Paul Steinhardt, Andreas Albrecht, and others. Guth realized that a sudden, ultra-rapid stretching of the universe could take a tiny uniform patch and expand it to a size where it ultimately would grow and become the observable universe. During the fleeting instant of inflation, any irregularities in the primordial cosmos would be propelled beyond detection, offering a kind of blank slate. It is like taking a crinkled tablecloth and stretching it out so quickly that it appears flat on a tabletop and any wrinkles left are off the table and out of view. Only tiny, jiggling quantum fluctuations would disturb the uniformity; these fluctuations would be the seeds of the galaxies and galaxy clusters we see today.Inflation solved critical problems in cosmology, but it also split the Big Bang into distinct phases: In the inflationary portrait, the creation of almost all of the matter and energy in the universe takes place at the close of the inflationary period, through a process called “reheating,” rather than before inflation. Reheating involves a massive release of energy from inflation’s driving engine: an entity called the “inflaton,” thought to be a fluctuating energy field that ignited ultra-rapid cosmic expansion. Theorists think that at the end of inflation, the inflaton field released an enormous reservoir of potential energy into space—which, following Einstein’s famous equivalence between energy and mass, converted into a deluge of particles. Before then, because stretching causes cooling, the universe was actually relatively cold. As the cosmos rapidly expanded, its hot initial temperature dropped by a factor of many thousand (the precise amount depends on the particular model), becoming extraordinarily hot only after reheating. If you feel that an event should be fiery if it’s going to be called the “Big Bang,” then reheating, not the cosmic dawn, was the true “bang.” (Max Tegmark has made this case in a recent blog post.)