A 50-year-old debate has at last been settled: the highest-energy cosmic rays do not originate in our own Galaxy but in galaxies located tens or even hundreds of millions of light years away. The evidence comes from the Pierre Auger Observatory in Argentina, which has been gathering data since 2004 about these particles that constantly bombard the Earth. The CNRS is the observatory's principal French funding agency.
Fifty years ago, scientists discovered that the Earth is occasionally hit by cosmic rays of enormous energies. Since then, they have argued about the source of those ultra-high energy cosmic rays -- whether they came from our galaxy or outside the Milky Way. The answer is a galaxy or galaxies far, far away, according to a report published Sept. 22 in Science by the Pierre Auger Collaboration.
International collaboration by scientists with the Pierre Auger Observatory confirms that most of the highest energy cosmic rays that reach the Earth come from outside the Milky Way galaxy.
Where do cosmic rays come from? Solving a 50-year-old mystery, a collaboration of researchers has discovered it's much farther than the Milky Way.
NASA's Hubble Space Telescope helped an international team of astronomers find that an unusual object in the asteroid belt is, in fact, two asteroids orbiting each other that have comet-like features. These include a bright halo of material, called a coma, and a long tail of dust.
The most-studied galaxy in the universe -- the Milky Way -- might not be as 'typical' as previously thought, according to a new study. Early results from the Satellites Around Galactic Analogs (SAGA) Survey indicate that the Milky Way's satellites are much more tranquil than other systems of comparable luminosity and environment. Many satellites of those 'sibling' galaxies are actively pumping out new stars, but the Milky Way's satellites are mostly inert, the researchers found.
Astronomers have used ALMA to capture a strikingly beautiful view of a delicate bubble of expelled material around the exotic red star U Antliae. These observations will help astronomers to better understand how stars evolve during the later stages of their life-cycles.
Astrophysicists from Moscow State University have found a new way to estimate the mass of supermassive black holes outside our galaxy, even if these holes are barely detectable. The results of the study were published in the Astronomy and Astrophysics journal
Scientists from NCRA-TIFR, Pune, and RIT, USA, have discovered the closest ever binary supermassive black hole system in a spiral galaxy NGC 7674, located about 400 million light years from Earth. The apparent separation of the two black holes in the binary system is less than one light year. This is direct observational proof of the existence of close supermassive black hole binary systems inside galaxies, which are potential sources of gravitational waves.
Could the flapping of a butterfly's wings in Costa Rica set off a hurricane in California? For most people, this hypothetical scenario may be difficult to imagine on Earth -- particularly when a real disaster strikes. Yet, in space, similarly small fluctuations in the solar wind as it streams toward the Earth's magnetic shield actually can affect the speed and strength of 'space hurricanes,' researcher Katariina Nykyri of Embry-Riddle Aeronautical University has reported in in the Journal of Geophysical Research - Space Physics.