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.