Was there a time before the big bang?

A new generation of telescopes could test new theories that there was a time before the big bang occurred.

According to big bang theory, the universe started out as a singularity – a single point of infinite density and energy – and then went through a time where it expanded at an extremely rapid rate, much faster than the speed of light. This period is known as “inflation”.  Inflation explains why light travels in straight lines – inflation smoothed out the universe’s curves and therefore made space-time flat. The overall pattern of the galaxies as they are seen now can also be explained by ripples occurring during inflation. 

However, inflation should have caused powerful gravitational waves that would have distorted the cosmic microwave background radiation – the heat leftover from the big bang.  Such distortions have never been observed by telescopes. 

In the past fifteen years, scientists have theorised that there was a time before the big bang during which the universe contracted and later rebounded, and that its effects can be seen in the structure of the current universe. However, many of the theories that were developed were rejected because they implied that ripples which happened before the big bang cold continue to exist when the universe was a singularity, and because they were based on string theory, which requires undetected dimensions beyond space time, and which is not popular with many scientists. 

In the past few months, a number of new models of a cycling universe have developed, all of which require no dimensions beyond the existence of space and time, and many of which do not require the existence of a singularity. For example, two models suggest that a strong push from a “ghost condensate”- a fluid of exotic particles that can exert tremendous pressure-kept the prior universe from collapsing to a point. 

More sensitive future telescopes, such as the Planck Surveyor, should help determine if any of the new models could be correct.  The new models of a cycling universe should have resulted in waves 50 times weaker than those that would be generated by inflation. If these telescopes still do not observe the distortions in the microwave background that inflation could have created, the idea of a time before the big bang would have more support.