Early scientific results were announced Jan. 11. Planck is far from finished its mission, and yet his first crop has already attracted much interest. Explanations ...
- What is the CMB?
- What is it to draw a map?
To understand the interests and achievements of the mission, a little introduction is needed.
The CMB
Also known as fossil radiation, or CMB for Cosmic Microwave Background, the radiation there is a little more 13 billion years is the first visible light of the universe. At a time when the universe was still quite young (about 380 000 years), the atoms are formed by capturing electrons. The universe opaque imprisoning its electrons becomes suddenly (in astronomical terms) transparent. This "flash" very energetic at that time had ample time to cool, until being observed today in low-energy wavelength: microwaves.
If researchers are so interested is because the CMB is not the same in all directions . If the image that we receive today from this flash is not fully smooth but grainy is that the matter which it has issued more than 13 billion years was not homogeneous. The CMB is the main source of data concerning the first moments of the universe. Its mapping is therefore of great interest to science, and informs us about the formation of the earliest structures.
Two NASA satellites were preceded Planck in this task: COBE (launched in 1989) and WMAP (launched in 2001). The European Commission embarked instruments far more sensitive and should provide a map much more accurate. Planck
Planck space telescope is specialized in the microwave the world's most accurate: his instruments are 600 times more sensitive than that getting COBE. To achieve this, he had to face several technological challenges, including that cool the detectors to very low temperature (0.1 Kelvin). As the satellite has exhausted its reserves of cryogenic liquid, Planck will be the coldest world with the exception of a few terrestrial laboratories. This feat alone is likely to please the researchers. But that's not all: the processing of data to draw the map as promised gives astronomers an opportunity to unpublished observations.
Among the twenty scientific publications with the first results of Planck, we can note the work done on the cosmological infrared radiation. Like the cosmic microwave background, the cosmological infrared radiation (or IPC Cosmic Infrared Background ) was issued long ago, then cooled to a longer wavelength. The IBC is the image, tarnished by time, the very first galaxies. His study is complicated by the abundance of infrared sources that parasitize the data, so that we can study only in areas that are not too many of these unwanted sources (see below).
catalog compact sources
Planck space telescope has the distinction to observe the entire sky. It is therefore possible to provide researchers with a fairly complete catalog of radio sources and microwave for the whole sky.
More than 15 000 objects were detected, their contact details made available to the scientific community. This is the first catalog of objects that emit infrared to radio waves on the entire sky. At these wavelengths, the detected objects are very cold, or so distant objects whose light has had time to cool before reaching us. There is therefore a bit of everything: very cold molecular clouds in our galaxy, distant galaxy or cluster of galaxies, but also a large number of unidentified objects.
The first crop of Planck up already a few sails on the mysteries of the universe even though the ultimate objective of the mission is not reached. This means the hopes aroused by the Space Telescope, which is anxiously awaiting the result: the most accurate map ever drawn of the CMB. I leave you in the meantime enjoy the sky as it is seen by Planck. The outline of the Milky Way is still visible. It is destined to disappear to make way for CMB.
Public Official Website of the Planck mission: http://public.planck.fr/
Planck on the site of the ESA : http://sci.esa.int/science-e/www/area/index.cfm?fareaid=17
First scientific publications: http://www.sciops.esa.int/ index.php? project = PLANCK & page = Planck_Published_Papers
More about the CMB: http://background.uchicago.edu/
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