Ask A Scientist© Astronomy Archive

Question:
Big Bang Theory
What things do we have that support this theory?  Where does it come from? And
is there evidence that is going against the theory?
Tammy

Answer:  The major support is that we can detect the expanded and cooled photons 
from the earliest history of the universe.  The temperature of this background
agrees with the calculation of the big bang. Many other conditions like the
amount of certain elements are also in agreement.  There are always people looki ng for changes in
the details, but most scientists find the data very convincing that it existed.  
on the other hand..recent measurements of the Hubbel Constant put the age of the 
universe (according to the standard Big Bang theory) *younger* than the oldest k nown stars (or
is it galaxies...?)
Personally, I have no doubt that the standard Big Bang theory will have to be
modified: physicists hate mathematical singularities that are
supposed to have a real, physical manifestation.  The theory of Black H Holes
solved the problem of gravitational singularities, but I'm not aware of any "Big 
Bang-like" theories that deal with the singularity at cosmological time = 0
hawley