Infrared image of cold gas (in blue) that has collected around a massive star (hidden in the center of the image) that is several million years old. A plasma thruster could clean up space A novel thruster just half the size of a thimble has been designed by a French physicist. What makes it unusual is that it is a plasma thruster in which the conventional coils have been replaced by permanent magnets. The thruster, which is both highly efficient and low on energy consumption, will be installed on a miniature satellite to carry out a deorbiting test. If the operation is successful, the microthruster could provide an effective answer to the ever-growing problem of space pollution. The Sun’s genealogy finally revealed Inclusions in meteorites show that aluminum-26 was present in the early Solar System, although there is no definitive explanation for this. Now, by combining astronomical observations with mathematical calculations, researchers have shed light on the origin of this radioactive isotope of aluminum. It was carried in by the wind from a massive star born a few million years before the Sun. Huge amounts of hydrogen gas collected in the vicinity of this ancestral star, generating thousands of new stars, one of which was our Sun. 51 The expansion of the universe under scrutiny ---------------------------------------------------------------------------------------------------------------------------------------------------------- By managing to measure the expansion of the universe five billion years ago and then ten billion years ago, scientists working on the BOSS (Baryon Oscillations Spectroscopic Survey) project have for the first time detected the deceleration of the expansion that preceded the current phase of accelerating expansion. The first stage of their work consisted in analyzing the 250,000 galaxies identified by the US telescope SDSS (Sloan Digital Sky Survey). This enabled them to reconstruct the expansion of the universe over the past six billion years with unprecedented accuracy. However, to continue investigating prior events, the researchers were unable to base their research on the study of galaxies, as these are not bright enough. The BOSS team therefore focused on the analysis of 50,000 quasars, which are both distant and extremely bright objects, in order to draw up the first three-dimensional map of the universe at a time when expansion was still slowing down. ArXiv March-June 2012 online Galaxies change “diet” with age The growth of adolescent galaxies, between three and five billion years after the Big Bang, went through two distinct stages, reveal new observations of the distant universe by an international team using the European Southern Observatory (ESO)’s Very Large Telescope in Chile. The study shows that initially, smooth gas flow mainly contributed to the formation of galaxies in the early universe before galaxy mergers took over, allowing the bigger galaxies to cannibalize smaller ones. Astronomy & Astrophysics February 2012 online Changing the color of stars to see them better An international collaboration has developed a novel imaging method that allows celestial objects emitting in the infrared to be studied in the visible. After successful tests in the laboratory, the researchers have shown that the method works well in a real-life situation. Using a small telescope at the Mauna Kea observatory in Hawaii, they succeeded in converting infrared light from three stars to a signal at visible wavelengths. This innovative method, although initially intended for astronomy, could find applications in a host of other fields. Monthly Notices of the Royal Astronomical Society October 2012 online Astronomy & Astrophysics August 2012 online With its 28-meter mirror, HESS-II, inaugurated on July 26, 2012 in Namibia, is now the largest gamma-ray telescope ever built. The camera and its integrated electronic system make up most of France’s contribution to this remarkable telescope, which will enable astronomers to identify some of the most violent phenomena in the universe. --------------------------------------------------- 3 rd International Conference on Space Propulsion May 2012, Bordeaux 2012 A year at CNRS
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