Expert: James Gort - 1/12/2007

Question
Scientists say the universe is expanding. That's their evidence for the big bang. But scientists now say it is slowing down and will eventually stop and go backwards. So surely this could just mean that the universe is fluctuating back and forth over a certain distance and that there never was a big bang.

Answer
Hello Opium17,

If you want me to justify the Big Bang, then you've asked the wrong person.  If, on the other hand, you'd like an honest and unbiased answer, then I think you've come to the right place.

The Big Bang advocates mainly use two pieces of observational evidence to indicate such an 'event' happened (if you can call the beginning of space and time an 'event'!).  There is an apparent red-shift of light from distant galaxies, interpreted by many to indicate the galaxies are receding (an example of the Doppler shift).  The other evidence often cited is the cosmic microwave background, considered by many to be remnants of the Big Bang.  The entire argument is based mainly on these two items.  Homogeneity of galactic counts (even "looking back in time" close to the event itself) is largely ignored, since it contradicts the Big Bang argument.

However, some noted astronomers have questioned the red-shift interpretation.  Not only might the red-shift      NOT indicate recession (and slowing down, as you note), but there are other very plausible explanations.  And if you insist on the velocity interpretation of the red-shift, there are major problems (inconsistencies) which must be solved.  I refer you to an excellent book by Halton Arp (an outstanding astronomer specializing in galaxies - the Arp Atlas of Peculiar Galaxies is still a standard), entitled "Seeing Red:  Redshifts, Cosmology, and Academic Science".  He makes many excellent arguments for other (and better) interpretations of the red-shift.

I'd also like to refer you to another excellent book by three leading astrophysicists - Hoyle, Burbidge, and Narlikar - entitled "A Different Approach to Cosmology - From a Static Universe Through the Big Bang Towards Reality".  These authors make a very convincing argument that the Big Bang is not the best model for the universe, and has major problems which have not been addressed.  They argue for a quasi steady-state universe (including possible oscillations).  A must read if you're really interested in the subject.

So, no, I cannot justify the Big Bang.  There's much evidence that other models are better from many standpoints.  But it will take much to change the current momentum in many scientific circles to embrace these alternate ideas.

Hope this gives you a well-rounded picture of current thinking on this subject.

Prof. James Gort