They are two such as eyes whose nature we have

They are two, such as eyes whose nature we have. A door the name of the astronomer who discovered infrared radiation, the other that of the physicist who explained the way in which a body in thermal equilibrium (a "black body" in the jargon of physicists) emits radiation. Launched on 14 May 2009, Kourou by an Ariane 5 rocket, the space telescope Herschel and Planck orbit currently to about 1.5 million kilometres from Earth on a point of balance between the fields of gravity of our planet and the Sun, called "second Lagrange point".

A total of EUR 2 billion cost, these two missions of the space agency, implemented by Thales Alenia Space, will enable the old Continent to hand in the study of the universe after the harvest of data collected by the Americans with their Spitzer and WMAP satellites, launched in August 2003 and June 2001: Herschel and Planck both represent a considerable over their predecessors technological jump.

Planck, the smaller of the two telescopes, will be honoured throughout this week in the city of science and industry, where an International Conference is organized to present the scientific community a first series of results. Turning on itself to sweep all of the sky, this satellite has already delivered, in July, his first photograph of the observable universe.

Fruit of months of "break time" in nine different frequency bands, the photo is a little consider the palette of Monet painting "Water lilies": a beautiful oval speckled blue, green and yellow spots helmed by a wide red stripe in the middle. The stripe is our Galaxy, the milky way, by the slice. Our immediate environment, therefore, even if the large cloud of more than 200 billion stars stretches all similarly about 100,000 light years away. As we are part, cosmologists speak to his words of "foreground". It is on him that bear most of the preliminary data which will be communicated to scientists around the world this week. A point of vital before moving on to serious things.

As the main object of study of Planck is the "background", i.e. the distant universe. Or, what amounts to the same, the young, since universe, the speed of light in vacuum is not infinite (but of the order of 300,000 km/s), more far seen in space, more far back in time.

In this regard, Planck is a wonderful machine, worthy of H.G. Wells. Before dying of his beautiful death, end of 2012, without liquid helium to cool its instruments, the satellite took the time to send us four, even five surveys complete sky, similar and complementary to that of July 2010. Identified that 200 scientists involved in the consortium will analyze and "overlap" to obtain the most accurate map ever made to date in the universe, it was in there are 13.7 billion years, or almost at birth - this famous big bang at the origin of everything!

That we will show this map Always the same mouchetis of blue, green and yellow spots forming what cosmologists call the "cosmological diffuse background." Also called "fossil light" discovered by chance in 1964 by two engineers of the Bell Labs, this microwave, perfect example of black body radiation is the oldest "image" of the universe that will never contemplate. It was issued "that" 380.000 years after the big bang - straw, the cosmic scale - at the time where the cooling caused by the expansion of the universe helped the photons decouple material, making it suddenly transparent. Prior to this "fiat lux", the soup of particles of origins was so dense and hot that photons could not be move freely: the universe was opaque.

When these primordial photons were released, they were still very hot: 3,000 degrees Kelvin (either 3,000 degrees Celsius above absolute zero, which is-273,15 C). Throughout their journey of 13.7 billion years, they have had time to cool before finishing their race Planck sensors: temperature decreased by a factor of 1,100 to fall at 2,725 K. Although remarkably homogeneous from one end of the universe to the other, this average temperature has however, in places, of tiny variations of a few tens to hundreds of millionths of a degree of magnitude, to variations in density in the cosmic soup due. Are for the most part these "anisotropies", so called, that cosmologists will be able to better study by Planck.

Their analysis is expected to more precisely estimate 20 of cosmological parameters, such as the exact age of the universe or its form - is it "flat", as our mundane space Euclidean, or curve, which would more resemble a sphere or a horse saddle In fact, this is all the scenario (based on Einstein's general relativity) the history of the universe since the big bang - what specialists call the "standard model of cosmology" - which will come out stronger, or will be partially to rewrite.

A perspective that moves not Jean-Loup Puget, responsible for the Planck-HFI Consortium: "Planck will enable us to improve our knowledge of cosmological parameters globally consistent between them." Any significant difference in the value of one of them would be a sign of a contradiction somewhere, and therefore something very exciting for any cosmologist self-respecting. "Outcome of the races early 2013.