AMS-02 on the hunt for antimatter Developed by an international collaboration, the AMS-02 particle detector has now reached the International Space Station and is set to investigate some of the greatest mysteries in the Universe. Its main mission is to track particles of antimatter in an attempt to detect the remains of the primordial antimatter that was produced in (almost) identical amounts to ordinary matter, and which may or may not have totally disappeared. AMS-02 may also help to solve the mystery of dark matter, an invisible and strange component of our Universe that could make up more than 80% of its total mass. Preparing the Genesis concentrator target, prior to the isotopic analysis of nitrogen in solar wind. Isotopic signature of the Sun revealed Oldest star in the Galaxy spotted By studying samples of solar wind collected by the Genesis spacecraft launched by NASA in 2001, a team of geochemists was able to Using the European Southern Observatory’s Very Large Telescope in Chile, a establish the abundance of nitrogen isotopes in the Sun and, by European team has detected the oldest star discovered so far in our Galaxy. extension, in the gas and dust cloud that gave rise to the bodies in the Located in the heart of the constellation Leo, its mass is slightly smaller than solar system. This work shows that the isotope nitrogen-15 in planets that of our Sun. Possibly dating back more than 13 billion years, the star is like the Earth is 60% higher than it was in the initial composition of mainly composed of the light elements hydrogen and helium, produced in the the solar system, due to as yet unknown phenomena that could be Big Bang. Heavy chemical elements such as carbon and silicon, on the other linked to the intense luminosity of the early Sun. hand, are almost completely absent. This data contradicts the theoretical models used for predicting the formation of this type of low-mass star. Science June 2011 Nature September 2011 Giant planets may have given rise to their younger terrestrial counterparts ----------------------------------------------------------------------------------------------------------------------------------- The study of exoplanets has shown that some giant planets can migrate close to their star. On the basis of this observation and using countless numerical simulations, an international team of astrophysicists has proposed an original model that can describe the behavior of our solar system before the formation of the terrestrial planets. In the scenario they envisage, Jupiter migrated towards the Sun as far as the present position of Mars. During this journey, it pushed aside all the material in its path, leading to the formation of a disk of material in the immediate vicinity of the Sun. This created the necessary conditions for the formation of the terrestrial planets and the asteroid belt. Subsequently, Saturn, once formed, may in turn have migrated towards the Sun. Under its influence, Jupiter may then have veered off course until it reached its current position, beyond the asteroid belt. The researchers are now attempting to include the formation of Uranus and Neptune in this scenario. Nature June 2011 First results from Planck The first edition of the catalog of galactic and extragalactic sources detected by the European Space Agency’s Planck spacecraft has Dark matter emerges from the shadows been published. The catalog—the first of its kind since Planck was placed in orbit in July 2009—lists thousands of objects, such as Two years after its launch, the EDELWEISS experiment dedicated to distant galaxies, which emit light at the same wavelengths as the the search for particles called WIMPs (Weakly Interacting Massive cosmic background radiation. Analyzing these sources of interference Particles) has produced its first results. Among the five candidate is a prerequisite for Planck to achieve its ultimate goal, which is particles spotted by the ten detectors, which are protected from to provide an image of the universe as it was 380,000 years after cosmic rays and ambient radioactivity, some could be constituents the Big Bang. of dark matter. To confirm this hypothesis, the physicists of the EDELWEISS collaboration will soon deploy a new generation of detectors able to track WIMPs with even greater sensitivity. Nature News Blog March 2011 49 2011 A year at CNRS
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