by John Bahcall, Institute for Advanced Study, Princeton, NJ
Every astronomer will remember where he or she was when they first heard the WMAP results. I certainly will.
For cosmology, the formal announcement today represents a `rite of passage’ from speculation to precision science.
I am thrilled by the precision of the results we have just heard from Chuck and David.
However, I am astounded by what they mean. Before WMAP, astronomers had assembled an implausible model of the universe with a little bit of ordinary matter; a significant portion of dark matter (whatever that is); and a whole lot of dark energy (another strange beast). I confess; I was skeptical.
But, the WMAP measurements convinced me. The error bars are tiny. There are multiple, redundant checks on the experiment.
The way the world is, is the way WMAP sees the world. We will have to understand this universe. We have no choice.
A natural question, given so many important measurements by WMAP, is: What is the most revolutionary result? In my opinion, the most revolutionary result is that there are no revolutionary results. WMAP has confirmed with exquisite precision the crazy and unlikely scenario that astronomers and physicists cooked up based upon incomplete evidence. Incredibly, everybody got it essentially right.
Lets consider a human analogy to try to appreciate better what WMAP has achieved.
Suppose we equate a 50-year-old man to the current universe, then the analogy is correct if the epoch that is studied by WMAP is a newly born baby, only 12 hours old. . The WMAP scientists have measured for the infant universe the total body weight, the length of the legs, the size of the ears, and the amount of hair
What the WMAP scientists have done is the equivalent of a doctor using the results of an annual physical checkup to infer correctly the detailed physical characteristics of the same individual when he was only 12 hours old.
I have distinguished colleagues, historians, who argue with great erudition about what events occurred a thousand or two thousand years ago. The WMAP results prove that astronomers and physicists know what happened in a broad sense in the universe almost 14 billion years ago.
For me, the bottom line of today’s announcement is that we live in a crazy universe whose defining behavior we know precisely for the last 14 billion years.
The WMAP achievement makes me proud to be an astrophysicist.