What facts disprove the Big Bang theory?

Right now, the only serious problem facing Big Bang cosmology is that the NASA COBE and WMAP satellites have shown that the cosmic background radiation is slightly lumpy in a way predicted by a version of big bang cosmology called 'inflationary big bang cosmology'. This version, however, requires that the universe have an average density that is exactly its 'critical density' given how fast it is currently expanding. But when astronomers use a variety of independent observational techniques to measure what the density of our universe is in the form of stars and gas, the numbers seem to come up short by a factor between 2 and 5.

The recent study of supernovae located some 5 billion light years away have, again, indicated that the universe seems to have about five times less density in stars and gas than inflationary cosmology demands that it must have, to be consistent with the COBE measurements.

It looked like this was the biggest failure of Big Bang cosmology, but then new data stepped in to change this picture drastically.

The spectacular results of the WMAP satellite, along with the results from COBE and a number of other high-precision studies of the cosmic background radiation have now established that the universe is 13.7 billion years old, and that it is exactly 'flat' meaning that its density is exactly critical ( 1.0). Also, the amount of this density in stars and gas is only 4%. The rest is in the form of Dark Matter (23%) and Dark Energy (73%) and it is this Dark Energy that is causing our universe to expand at an accelerated pace.

Big Bang cosmology, with the addition of inflation, predicted the kind of lumpiness we see in the cosmic background radiation, and an earlier version of big bang cosmology with an added 'cosmological constant' predicted we would be living in an accelerated universe, so

at the present time Big Bang Cosmology rules!!

Return to Ask the Astronomer