Most Amazing Time Lapse Video of Milky Way Ever Made. Seriously. Galaxy Zoo. Ghostly gamma-ray beams blast from Milky Way's center. (Phys.org) -- As galaxies go, our Milky Way is pretty quiet. Active galaxies have cores that glow brightly, powered by supermassive black holes swallowing material, and often spit twin jets in opposite directions. In contrast, the Milky Way's center shows little activity.
But it wasn't always so peaceful. New evidence of ghostly gamma-ray beams suggests that the Milky Way's central black hole was much more active in the past. "These faint jets are a ghost or after-image of what existed a million years ago," said Meng Su, an astronomer at the Harvard-Smithsonian Center for Astrophysics (CfA), and lead author of a new paper in the Astrophysical Journal. "They strengthen the case for an active galactic nucleus in the Milky Way's relatively recent past," he added. The two beams, or jets, were revealed by NASA's Fermi space telescope. The newfound jets may be related to mysterious gamma-ray bubbles that Fermi detected in 2010. The two structures also formed differently. Daily Galaxy. 7 Good Reasons Why There Might Be Life on Other Planets. Top 3 Questions People Ask an Astrophysicist (and Answers)
Credit: Alain R. | Wikimedia Commons Whether he's teaching class, socializing at a cocktail party or talking to visitors at the planetarium where he works, Charles Liu knows that sooner or later he's going to get asked at least one of three questions: Is there a god? Are there aliens? What would happen if I fell into a black hole? "I've never been in a public environment where people know what I do where at least one of these questions was not asked," Liu said. He is an astrophysics professor at the City University of New York's College of Staten Island and an associate at the Hayden Planetarium at the American Museum of Natural History. Over the years, Liu has developed some pretty solid answers, based on scientific evidence and his own opinion, to those three burning questions.
Does a galaxy filled with habitable planets mean humanity is doomed? Scientists Now Know: We're From Sagittarius Dwarf Galaxy! Scientists Now Know: We're Not From Here! Summary & comments by Dan Eden for Viewzone "This first full-sky map of Sagittarius shows its extensive interaction with the Milky Way," Majewski said. "Both stars and star clusters now in the outer parts of the Milky Way have been 'stolen' from Sagittarius as the gravitational forces of the Milky Way nibbled away at its dwarf companion. This one vivid example shows that the Milky Way grows by eating its smaller neighbors. " The study's map of M giants depicts 2 billion years of Sagittarius stripping by the Milky Way, and suggests that Sagittarius has reached a critical phase in what had been a slow dance of death. "After slow, continuous gnawing by the Milky Way, Sagittarius has been whittled down to the point that it cannot hold itself together much longer," said 2MASS Science Team member and study co-author Martin Weinberg of the University of Massachusetts.
Does this mean we are at a unique moment in the life of our galaxy? From Dan Eden: Hi Dan, Galaxies. Individual Galaxies. Milky Way. 'Habitable' planet discovered circling Tau Ceti star | Science. A planet with conditions that could support life orbits a twin neighbour of the sun visible to the naked eye, scientists have revealed. The world is one of five thought to be circling Tau Ceti, a star just 12 light years away that is almost identical to the sun. Astronomers estimate the Tau Ceti planets to be two to six times bigger than Earth. One of them, with five times the Earth's mass, lies in the star's "habitable zone". Also known as the "Goldilocks zone", this is the orbital region that is neither too hot nor too cold to allow liquid surface water and, potentially, life. Details of the discovery are to appear in the journal Astronomy & Astrophysics. Because of the difficulties involved in detecting extra-solar planets, most found so far have had high masses.
Scientists found the planets using a highly sensitive technique that combined data from more than 6,000 observations from three different telescopes. Extragalactic astronomy. Galaxies in the Hubble Deep Field Extragalactic astronomy is the branch of astronomy concerned with objects outside our own Milky Way galaxy. In other words, it is the study of all astronomical objects which are not covered by galactic astronomy, the next level of galactic astronomy.
As instrumentation has improved, more distant objects can now be examined in detail. It is therefore useful to sub-divide this branch into Near-Extragalactic Astronomy and Far-Extragalactic Astronomy. The former deals with objects such as the galaxies of our Local Group, which are close enough to allow very detailed analyses of their contents (e.g. supernova remnants, stellar associations). The latter describes the study of objects sufficiently far away that only the brightest phenomena are observable. Some topics include: References See also Galactic astronomy. Galactic astronomy is the study of our own Milky Way galaxy and all its contents. This is in contrast to extragalactic astronomy, which is the study of everything outside our galaxy, including all other galaxies. Galactic astronomy should not be confused with galaxy formation and evolution, which is the general study of galaxies, their formation, structure, components, dynamics, interactions, and the range of forms they take.
Our own Milky Way galaxy, where our Solar System belongs, is in many ways the best studied galaxy, although important parts of it are obscured from view in visible wavelengths by regions of cosmic dust. The development of radio astronomy, infrared astronomy and submillimetre astronomy in the 20th Century allowed the gas and dust of the Milky Way to be mapped for the first time.
Subcategories A standard set of subcategories is used by astronomical journals to split up the subject of Galactic Astronomy: Stellar populations See also Universe's most distant galaxy discovered. Texas A&M University and the University of Texas at Austin may be former football rivals, but the Lone Star State's two research giants have teamed up to detect the most distant spectroscopically confirmed galaxy ever found—one created within 700 million years after the Big Bang. The research is published in the most recent edition of the journal Nature. "It's exciting to know we're the first people in the world to see this," said Vithal Tilvi, a Texas A&M postdoctoral research associate and co-author of the paper, set to be available online after Oct. 24. "It raises interesting questions about the origins and the evolution of the universe. " The paper's lead author is Steven Finkelstein, an assistant professor at the University of Texas at Austin and 2011 Hubble Fellow who previously was a postdoctoral research associate at Texas A&M under the mentorship of Texas A&M astrophysicist Casey Papovich, who is second author as well as current mentor to Tilvi.