In contrast to the majority of the speakers at the meeting, Professor John Barrow FRS of the University of Cambridge is a cosmologist rather than a metrologist. His research is concerned with how the fundamental physical constants of nature might not be fixed, as some would suggest, but can change with the passage of time.
The fundamental constants play a crucial role in cosmology and many theories
about the origins and the end of the universe and all that happens on a
cosmological scale in between hinge on these values. Barrow explained how
researchers can use astronomical observations to place strong limits on just
how far the supposed "constants" of nature might change over the
cosmologically significant timescales of billions of years.
He pointed out that observations of the absorption spectra of quasars,
considered among the most distant, and so ancient of astronomical objects,
have provided researchers with a substantial body of evidence consistent
with a very slow change in one particularly relevant constant, the so-called
fine structure constant (?) of electromagnetic interactions, at a level that
is below the detection threshold of current scientific experiments. The fine
structure constant provides a measure of the intrinsic strength of the
strength of electromagnetic forces in the universe. This constant is one
defined by CODATA with no units, in other words it is self-consistent and
relies on knowing no other values, whether of mass, time, or space. It is a
pure number and, asked Barrow, why does such a number have the value it
does, are they truly fundamental and unchanging or could they have other
values or change with time?
Fundamental constants are among the most accurately measured quantities in
the whole of science, added Barrow, but theoretically we are yet to explain
the value of any constant of nature. Some theoreticians had once hoped that
a so-called "Theory of Everything" would have the values pre-programmed in,
so that we could derive definitive values from this for all constants.
Current wisdom implies this is certainly not the case for all constants,
said Barrow, and many values may be produced by nature entirely at random.
Read on...
Timing Fundamental Constants