Abstract

The comparison of spectral lines of H2 observed in the present epoch to those
of some 11-12 billion years ago provides a tool to verify whether
the underlying forces of nature have changed over such a large
time interval. Such a procedure can be performed now that with
Very Large Telescopes, equipped with advanced spectrometers,
high resolution spectra can be obtained from high-redshifted objects.
The spectra of molecular hydrogen, measured with modern lasers
covering even extreme ultraviolet wavelengths, may reveal if one of the
fundamental constants has changed over time. An indication was found that
the proton-electron mass-ratio may have decreased by 0.002%. Further
work in this field is in progress and will be discussed.