The ultimate fate of the universe depends on exactly how much matter it contains. It could expand forever, with galaxies drifting further and further apart. However, if there is enough matter, gravity's pull will slow the expansion down, or even reverse it, ultimately leading to a Big Crunch.
New results from a test flight of the Boomerang balloon experiment imply that there is just enough matter to stop the expansion, but not to reverse it. This scenario is known as a "flat" universe. Boomerang measures the Cosmic Microwave Background radiation (CERN Courier November 1999 p13). Fluctuations in this background are evidence for the first clumping of matter - the seeds of galaxies we see today.
ESO visits CERN
Catherine
Cesarsky, director-general of the European Southern Observatory (ESO), visited CERN on 5
January. ESO has strong ties with CERN. Before the observatory moved to Garching in Germany,
it was based at the CERN site. Shown here are CERN's LHC division leader Philippe Lebrun
(right), Catherine Cesarsky and CERN physicist Daniel Treille, visiting the LHC magnet test
hall.