The universe from every angle Combining observations, statistical analyses, numerical calculations and laboratory experiments, astrophysicists are striving to understand the mechanisms at work in the universe, such as the formation of satellites around planets, the events that preceded the emergence of the first galaxies, and the way in which the expansion of the universe has changed throughout its long history. The Hubble space telescope performed a three-dimensional study of a cosmic filament of dark matter feeding this giant galaxy cluster. Half of the universe is made up of cosmic filaments ---------------------------------------------------------------------------------------------------------------------------------------------------------- Some numerical simulations aimed at verifying the predictions of the Big Bang theory suggest that the universe is structured as a “cosmic web” of filaments at whose nodes are very massive galaxy clusters. Using data from the Hubble Space Telescope, an international team has succeeded in carrying out a three-dimensional study of a cosmic filament of dark matter, just a few months after such a structure was observed for the first time. The astronomers have discovered that the filament is feeding one of the most massive galaxy clusters in the universe, and has a length exceeding 60 million light years. By extrapolating the measured mass of the filament to the whole of the cosmic web, the study determines that cosmic filaments should make up half the total mass of the universe. It should be possible to obtain a more precise estimation of this value, which is considerably greater than that predicted by theorists, when the very high-resolution James Webb Space Telescope is placed in orbit in 2018. New type of cosmic ray identified While reviewing data collected by XMM-Newton, the European Space Agency (ESA)’s X-ray astronomy satellite, French teams made a remarkable discovery: a new source of low-energy cosmic rays. The astrophysicists discovered that these cosmic rays were in all likelihood produced by the high-speed collision of a star cluster near the center of the galaxy with a gas cloud in its path. These findings should make it possible to identify new sources of ions in the interstellar medium. Astronomy & Astrophysics October 2012 online 50 Success for ChemCam’s first laser shots ChemCam, one of the principal instruments on board the NASA Mars Science Laboratory mission’s Curiosity rover, has successfully carried out its first analyses of Martian rocks. Jointly developed by French and US teams, the “chemical camera” fires a pulsed laser at the rock to be examined, part of which is vaporized and emits light. The light is analyzed by spectrometers and reveals the chemical composition of the sample. ChemCam should therefore play a key role in describing Martian geology. Monthly Notices of the Royal Astronomical Society October 2012 online A year at CNRS 2012
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