Page "Big Bang" Paragraph 14

These ideas were initially taken as postulates, but today there are efforts to test each of them.

For example, the first assumption has been tested by observations showing that largest possible deviation of the fine structure constant over much of the age of the universe is of order 10 < sup >− 5 </ sup >.

Also, general relativity has passed stringent tests on the scale of the Solar System and binary stars while extrapolation to cosmological scales has been validated by the empirical successes of various aspects of the Big Bang theory.