|
The last tests of the Ariane 5 rocket system have been finished,
and ESA's Planck satellite is sitting ready for launch at the Guiana
Space Centre in Kourou. Together with ESA's Space Telescope Herschel, Planck will start
into space on 14 May to begin its studies of the cosmic microwave radiation and of the clues
it gives about the Big Bang, the earliest phases of the cosmic history, and the structure and
composition of the Universe. The Max Planck Institute for Astrophysics (MPA) in Garching has
developed important software components for Planck and is getting ready to participate in the
analysis and scientific interpretation of the mission data.
According to the standard model of cosmology, our Universe began 13.7
billions years ago in a Big Bang, the origin of Space and Time.
The Cosmic Microwave Background (CMB) is the relic heat from this Big Bang, released
380.000 years after beginning and still travelling freely through space today. At that
early time, weak fluctuations of matter density were present, which are seen as variations
of temperature in the CMB. By observing these fluctuations cosmologists can infer how the
large-scale structure of today's Universe - galaxies, galaxy clusters and filaments - were formed.
The Planck satellite will be placed at the second Lagrangian point of the
Sun-Earth-Moon system (L2), located about 1.5 million kilometres away from the
Earth - four times the distance to the Moon. It will spin around its own axis,
which will always point towards the Sun, with each rotation recording another
strip of the sky and mapping its temperature to an accuracy of about one million
of a degree. The data are sent to Earth and turned into temperature maps of the
sky in data processing centres in France and Italy. What the maps look like depends
on certain characteristics of the Universe, for example on the curvature of space.
For hypothetic Universes with specified properties computer simulations using the
MPA software generate virtual maps, which will be compared with maps of the real sky.
"From the comparison we can draw conclusions about the structure of our own Universe,
for example how much ordinary matter and dark energy exist in it", explains Torsten Enßlin,
head of the Planck group at MPA.
The physics of structure formation and the formation of galaxies will be
studied via the so-called Sunyaev Zeldovich effect - the heating of CMB
photons by scattering in the atmosphere of galaxy clusters. Due to this
effect distant galaxy clusters become visible as "shadows" in front the
cosmic microwave background.
But the galaxy clusters are only the densest parts of the cosmic matter distribution.
85 percent of the cosmic matter remains invisible and dark. The composition of this Dark
Matter is still not known. From their computer simulations MPA cosmologists have shown how
the CMB is influenced the gravitational field of dark matter. The unseen structures of dark
matter can therefore be deduced from temperature variations in the CMB. This requires the
scientists to analyse the Planck data with statistical methods, obtaining important information
on the structure and future development of the Universe.
Moreover the mission is expected to detect thousands of distant objects in a frequency
range barely studied so far, and so to offer new insights into the physics of galaxies,
Active Galactic Nuclei and quasars in the submillimetre domain. These will show Planck
scientists energetic processes in the immediate vicinity of massive black holes.
Planck may also help us to understand the birth of the first stars in the Universe
and the structure of our own galaxy, the Milky Way.
Moreover the mission is expected to detect thousands of distant objects in a frequency range
barely studied so far, and so to offer new insights into the physics of galaxies,
Active Galactic Nuclei and quasars in the submillimetre domain. These will show
Planck scientists energetic processes in the immediate vicinity of massive black holes.
Planck may also help us to understand the birth of the first stars in the Universe and the
structure of our own galaxy, the Milky Way.
"With the start of the Planck satellite a dream comes true",
says Rashid Sunyaev, MPA director and pioneer of CMB research.
"Planck will provide the most precise data on the early Universe ever.
We have never been so close to the Big Bang." "We will understand the past
of our Universe and throw a glance at its future", adds Sunyaev's colleague Simon White.
"Will it keep on expanding for ever or some day collapse back upon itself? What is the
nature of the mysterious dark energy causing this expansion? Planck will give an answer
to many important questions of cosmology. The satellite is the most powerful tool ever
for studying the Cosmic Microwave Background developed."
Further Information
 Current Planck News
For further information please contact:
Dr. Torsten Enßlin
Max Planck Institute for Astrophysics
Phone: +49 89 30000-2243
Fax: +49 89 30000-3569
Email: ensslin mpa-garching.mpg.de
Prof. Dr. Simon White
Max Planck Institute for Astrophysics
Phone: +49 89 30000-2211
Fax: +49 89 30000-3569
Email: swhitempa-garching.mpg.de
Prof. Dr. Rashid Sunyaev
Max Planck Institute for Astrophysics
Phone: +49 89 30000-2244
Fax: +49 89 30000-3569
Email: rsunyaevmpa-garching.mpg.de
| 
