On the trail of the secret of our universe

Planck – a European time machine in search of the origin of all life

Every time you look at the sky, you make a little trip through time. When you look at a star that is 100,000 light years away from Earth, you see it as it was 100,000 years ago. It took all this time for his light to make him visible to us – a little human excursion into our prehistory. The path of the new European mission Planck leads much deeper into the past, on the traces of our origin – to the beginnings of our universe, about 13.7 billion years back in our time. It is to "first light" determine what carries information about our past and future – by observing the "oldest" detectable radiation, it will see the universe as it was almost at its origin.

Planck – on the tracks of our universe. Image: ESA

This mission was appropriately named after the famous German physicist Max Planck (1858-1947), who discovered the exact law of black hot radiation, the "Planck radiation law" , and thus launched the quantum theory that revolutionized physics. For the foundation of the quantum theory he received the Nobel Prize in Physics in 1918.

"Planck" undertakes for us 90 years later a journey through space and time, in order to answer for the astronomers and scientists some significant key questions to the origin theories of our universe, which are among other things: Does the universe continue its expansion forever, or does it collapse sometime?? How did the early phase of our universe look like? What are the basic conditions for the development of the universe structure?? What exactly is behind black matter and dark energy??

On the trail of the mystery of our universe

Max Planck at his desk around 1932. Image: German Historical Museum, Berlin

Questions, to which the scientists hope for answers, if at the end of July 2008 the satellite, for cost reasons together with the space telescope Herschel for the study of the emergence of galaxies, stars and planetary systems in the infrared range was developed, with a Ariane 5 from the spaceport in Kourou, French Guiana, on the way into the universe sets. However, the journey takes the pair of satellites Planck and Herschel to different points in space, so that they meet approx. Hour after the launch in the orbit separate.

After a ca. four-month "tour through space" Planck will have reached the destination of the journey, the Lagrange point L2. There, at a distance of 1.5 million kilometers from the earth – in extension of the connecting line sun-earth – the common gravitational pull of sun and earth acts on it, so that it runs as fast around the sun as our home planet despite the coarser solar distance.

Diagram of the Lagrangian points in association with the Sun-Earth system. Target point of the Planck mission: The Lagrange point (L2). Image: ESA

Planck mission

The precise investigation of the cosmic background radiation that has existed since the Big Bang is the goal of ESA’s Planck mission. Background radiation is a relic from the early days of our universe, created only a few hundred thousand years after the Big Bang, when the universe was still several thousand degrees hot. At this time, free protons and electrons, which had deflected the direction of radiation, combined to form neutral hydrogen atoms and the universe became transparent.

Since then, the photons of this radiation have been moving almost unhindered through space, only their energy decreased due to cosmic expansion, so that today they are in the microwave range with a temperature of only ca. 2.7 Kelvin can be received. They reach the earth with very high uniformity from all directions. The gross temperature deviation of ca. 0.1% is caused by the movement of the Milky Way relative to the microwave background. With ca. 0.001% and smaller, one observes structures whose origin lies in the early, light phase of the cosmological development.

Planck is now to carry out the most precise mapping of the cosmic microwave background radiation distributed in space to date. His instruments can perceive temperature differences of a few millionths of a degree and are said to scan the entire sky in nine wavelengths.

On the trail of the mystery of our universe

Cosmic background radiation recorded by the satellite WMAP. The volumes of this NASA mission, launched on 30. June 2001 launch, provides the best evidence yet that the Big Bang/Big Bang was at the beginning – and that the universe was expanding/expanding at a tremendous rate. Image: NASA/JPL

Technology "on board"

The Planck satellite has a telescope with a mirror diameter of 1.5 by 1.75 m and two high-power instruments that measure microwave radiation in different frequency bands. This allows the separation of galactic and extragalactic foreground sources and the sought cosmological radiation:

  1. HFI (High Frequency Instrument): 83 GHz – 1 THz Bolometric Detector Array, operating at 0.1 Kelvin, developed by the Institut d’Astrophysique Spatiale in Orsay, France. The high-frequency instrument consists of a series of 52 bolometric detectors that convert the radiation into heat, and at – 272.9°C operate. The amount of heat is then measured by a small electric thermometer. The HFI detectors operate in six frequency channels between 100 and 857 gigahertz.
  2. LFI (Low Frequency Instrument): 27 – 77 GHz "High Electron Mobility Transistor (HEMT) Radio Receiver Array", it was developed by the Istituto di Tecnologie e Studio delle Radiazioni Extraterrestri in Bologna in Italy. This low-frequency instrument consists of a series of 22 radio receivers operating at temperatures – 253°C. The receivers work grouped in four frequency channels between 30 and 100 gigahertz. They are based on what are known as HEMTs (High Electron Mobility Transistors) and work like transistor radios. The transistors amplify the signal collected by the antenna (telescope) and the amplified signal is then converted voltage. In a normal radio, the detected signal was passed on to a loudspeaker, but in Planck it is instead stored in a computer for later analysis.
On the trail of the secret of our universe

: Scientists of the Italian Institute IASF in Bologna are responsible for the smooth functioning of the Low Frequency Instrument (LFI). Image: IASF-BO

Software "Made in Germany"

In Germany, the Max Planck Institute for Astrophysics (MPA) in Garching is participating in this project.

MPA scientists develop software for data processing and information exchange within the two instrument consortia, they write simulation programs that are needed to test the data processing routines and later to analyze the observation data. In addition, they are building a data center to make the processed data available to the astronomical community.

At the end of February, the integration phase will be completed. Once completed, the Planck satellite will undergo a series of tests until early 2008, when it will be ready for launch at the end of July 2008.

Cost-saving mabnahme: The Planck (bottom) and Herschel(top) launch dual configuration in an Ariane 5. Image: ESA

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