 |
 
XXVII GENERAL ASSEMBLY
AUGUST 03 - 14, 2009 -
Rio de Janeiro - Brazil
Evolution of Structure in the Universe
Simon D.M. White www.mpa-garching.mpg.de
Max-Planck-Institut für Astrophysik
Garching-bei-München, Germany
August 10, 2009 - 18:00 hr
|
Recent studies of the Cosmic Microwave Background have provided us
with a high quality image of the Universe when it was only 380,000
years old. At that time it was a near-uniform mixture of hydrogen,
helium, dark matter and radiation, with no galaxies, no stars, no
planets and no people, indeed no atomic nuclei heavier than Lithium.
Under the action of gravity, the weak fluctuations observed in the
microwave sky evolved into the extraordinarily complex structure of
our present Universe. I will show how supercomputer simulations can
be used to demonstrate that such evolution does indeed reproduce the
observed properties of today's galaxies and large-scale structures,
thus confirming the extraordinary assumptions of the current structure
formation paradigm. Only a quarter of the energy density of the present
Universe is in gravitating matter; only a sixth of this matter is made
of atoms or other known particles; only 5 percent of this baryonic
material is currently inside galaxies. Most of today's Universe is in
the form of Dark Energy; most of the gravitating matter is Dark Matter;
and most of the baryons remain unseen in intergalactic space. The
properties of the fluctuations measured in the microwave sky suggest
that they originated very close to the Big Bang as quantum fluctuations
of the vacuum itself. Everything has formed from nothing.
|
|
National Organizing Committee - NOC
____________________________________________
www.astronomy2009.com.br
|
|