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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,

Quark Star (update) Some of the strange stuff that is coming out about quark stars: 1) that quark stars may be connected to dark matter (or even dark energy?) Some dark matter might just be “strangelets” roaming the cosmos, blasted free from quark stars: or 2) That some smaller sized black holes may actually be quark stars: “Some black holes may actually be ‘quark stars’:” or 3) The light given off by a quark star is called bremsstrahlung emissions. “quark star: gives off dim light (called bremsstrahlung emission), emitted by a thin layer of electrons on its surface:” or 4) It takes about 1.6 minutes to from a quark star from a neutron star. Like this: Like Loading...

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). Some topics include: References[edit] See also[edit]

Darkest exoplanet spotted by astronomers 12 August 2011Last updated at 11:09 By Jason Palmer Science and technology reporter, BBC News TrES-2b is literally darker, on average, than coal A dark alien world, blacker than coal, has been spotted by astronomers. The Jupiter-sized planet is orbiting its star at a distance of just five million km, and is likely to be at a temperature of some 1200C. The planet may be too hot to support reflective clouds like those we see in our own Solar System, but even that would not explain why it is so dark. The research will be published in the journal Monthly Notices of the Royal Astronomical Society. The planet, called TrES-2b, is so named because it was first spotted by the Trans-Atlantic Exoplanet Survey in 2006. It also lies in the field of view of the Kepler space telescope, whose primary mission is to spot exoplanets using extremely sensitive brightness measurements as far-flung worlds pass in front of their host stars. 'Exotic chemistry' Continue reading the main story

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. Subcategories[edit] A standard set of subcategories is used by astronomical journals to split up the subject of Galactic Astronomy:[citation needed] Stellar populations[edit] Interstellar medium[edit] See also[edit] External links[edit]

The Sounds of Pulsars A pulsar is a highly magnetised neutron star, with a radius of 10-15 km, having somewhat greater mass than the Sun which has a radius of approximately 1 million km. Radiation is beamed out along the magnetic poles and pulses of radiation are received as the beam crosses the Earth, in the same manner as the beam from a lighthouse causes flashes. Being enormous cosmic flywheels with a tick attached, they make some of the best clocks known to mankind. These sounds directly correspond to the radio-waves emitted by the brightest pulsars in the sky as received by some of the largest radio telescopes in the world.

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. Over the years, Liu has developed some pretty solid answers, based on scientific evidence and his own opinion, to those three burning questions. The Unsolved Mystery of Saturn's Hexagon -4 Times the Size of Earth "Cassini is indebted to Voyager for its many fascinating discoveries and for pavingthe way for Cassini," says Linda Spilker, Cassini project scientist at JPL, who started her career working on Voyager from 1977 to 1989. "On Cassini, we still compare our data to Voyager's and proudly build on Voyager's heritage." But the Voyager Mission left a few mysteries that Cassini has not yet solved. One of the most perplexing mysteries is Saturn's hexagpn. NASA scientists first spotted a hexagonal weather pattern when they stitched together Voyager images of Saturn's north pole. 'Now that we can see undulations and circular features instead of blobs in the hexagon, we can start trying to solve some of the unanswered questions about one of the most bizarre things we've ever seen in the solar system, said Kevin Baines, Atmospheric scientist at NASA's Jet Propulsion Laboratory after viewing Cassini images in 2009. After the sunlight faded, darkness shrouded the north pole for 15 years.

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.

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