Cosmic Times

Big hiss missed by others

The primary message of this article is to point out that theory and observation must both coordinate to advance our understanding of the Universe. A secondary message is that not all discoveries are planned – many of the richest discoveries happen by accident. It's one of the things that keeps science fun!

While the tools to find the echo of the Big Bang were known and could have been found by others, it is no big surprise that other researchers missed it. Theorists had been pursuing the cosmic microwave background (CMB), but most believed that it would be too faint to be detected.

Another factor that made the CMB difficult to find was that some theorists estimated a higher temperature for the CMB than was actually found. As discussed in the notes for the article "Murmur of a Bang", the spectrum of light of the CMB is that of a black-body. A black-body spectrum is characterized by the wavelength at which it peaks, corresponding to a characteristic temperature. Without knowing the characteristic temperature or the CMB, the signal CMB would be easy to miss.

Perhaps if Penzias and Wilson had not seen the paper by Dicke, they would have written the excess noise off to some "unattributable source", and continued with astronomical observations, oblivious to cosmological gem they had at their fingertips.

And as a side-note, a few other things in science that were discovered by accident include penicillin and gamma-ray bursts. It may be fun to have students find other examples.

Other resources

The following web page has more detailed information:

A service of the High Energy Astrophysics Science Archive Research Center (HEASARC), Dr. Alan Smale (Director), within the Astrophysics Science Division (ASD) at NASA/GSFC