The Universe Before the Big Bang

Martin Bojowald, a professor of phycics at Penn State University, presents his captivating ideas about “Loop Quantum Cosmology” in Once Before Time: A Whole Story of the Universe. "Will we ever," Bojowald asks, "with a precision that meets scientific standards, see the shape of the cosmos before the big bang? The answer to such questions remains open.

We have a crowd of indications and mathematical models for what might have occurred. A diverse set of outcomes within quantum gravity has discovered different phenomena significant for revealing what happened at the big bang. But for a reliable extrapolation, parameters would be needed with a precision far out of reach of current measurement accuracies.

"This does not, though, mean that it is impossible to answer questions about the whole prehistory of the universe," Bojowald adds. "Cosmology as well as theoretical investigations are presently moving forward and will result in unpredicted insights. Among them might well be experimentally confirmed knowledge of the universe before the big bang."

"Now the theory is poised to formulate hypotheses we can actually test," Bojowald concludes.

In the image above, a model universe, spirals out of nothingness (the so-called “State of Hell” of Loop Quantum Gravity) and then quickly expands to the right. The figure overlays states of the early universe at all times, categorized by its extension (vertical axis) and expansion rate (horizontal axis).:

"There’s a very deep human plea to understand origins and thus to trace the history of the cosmos back before the earliest periods for which cosmological theory and observations have provided some degree of scientific understanding," counters Columbia University theoretical mathematician, Peter Woit in his Not Even Wrong blog. "Unluckily this has led in recent years to a flood of over-hyped claims by physicists claiming to have a scientifically feasible theory of what happened “Before the Big Bang”.

"To qualify as legitimate science," Woit continues, "such claims require to be backed up by some conventional sort of evidence. This might take the form of experimental predictions, testable either now or in principle in the future. It might also take the form of a extremely constrained and beautiful theory whose success in other realms makes a compelling case that it could also explain experimentally inaccessible phenomena. I don’t know of any example of such pre-Big Bang scenarios now being sold to the public that comes even close to having such backing."