1998 Activity: Reasons for Belief


Since Isaac Newton formulated the universal law of gravity, stating that gravity is an attractive force acting between all masses in the universe, the idea of “anti-gravity” was considered fantasy. Nonetheless, Perlmutter’s and Kirshner’s findings have been widely accepted.  
Of course not all researchers have accepted the results uncritically.  There have been and will be challenges to the findings.  Further studies will certainly be undertaken using different methods to confirm changes that they observed in the expansion rate of the universe.  
Being skeptical of all findings—especially those that conflict with prior knowledge—is the coin of the realm in science. So it is important for scientists to be aware of the reasons for accepting or rejecting another scientist’s findings to be valid. Consider the following reasons:
  • Supporting evidence from other researchers:  This is the reason why the findings of the two teams are being given serious consideration.  Even though the results are unexpected and unexplained, both teams are well-respected for careful work.  
  • A mechanism that can explain the result:  “Dark energy” is not an explanation.  It is simply a name for the anti-gravity force that is causing acceleration.  In the history of science, many important findings were rejected until a mechanism was found. Alfred Wegener spent a lifetime trying to convince people that continents actually moved.  Although he marshaled a great deal of evidence the concept was not widely accepted until the mechanism of convection currents moving tectonic plates was proposed.
  • Confirmation of predictions:  New ideas that conflict with current understanding encounter resistance.  Einstein’s theory of general relativity proposed that a large mass would bend a (massless) beam of light.  That prediction conflicted with the idea that light moves in straight lines.  His theory gained substantial advantage over previous theories when Eddington observed that starlight was bent by the sun during a total eclipse by the precise amount Einstein's theory predicted.    
Consider the findings reported by Permultter and Kirshner.  Do you believe their result?  If you do, why?  If you do not, does one of the above reasons explain your skepticism?  What would it take to convince you?  What actions do you think cosmologists should undertake to test these findings?