Space Scan

NASA’s Swift satellite and Japan’s Suzaku X-ray observatory claimed to have discovered a new class of active galactic nuclei (AGN). AGN is distinguished from common galaxies as class, most luminous in the universe, such as quasars, blazars, and Seyfert galaxies, mostly powered by supermassive black holes, often emitting energy that equals energy of billion of stars from a region no larger than our solar system. Evidence with respect to the new type of AGN began over the past two years and with the help of Burst Alert Telescope (BAT) Jack Tueller, of NASA’s Goddard Space Flight Center, found nearby AGNs that were previously missed because their visible and ultraviolet light was smothered by gas and dust. These two newly discovered AGNs, targeted by Japan’s Suzaku, were found to be residing in the galaxies ESO 005-g004 and ESO297-G018, which are about 80 million and 350 million light years from Earth, respectively. This discovery will help scientists to explain why the previous X-ray AGN surveys missed these two AGNs as Suzaku was expected to cover broader range of X-ray energies than BAT, however, in spite of this advantage, it detected very low or medium range energies. As believed previously, AGNs are surrounded by donut-shaped ring of materials, which partially obscures our view of the black hole. Team member Richard Mushotzky thinks that a shell of obscuring material, which made it difficult for us to locate, surrounds these AGNs. We can see visible light from other types of AGN because there is scattered light. But in these two galaxies, all the light coming from the nucleus is totally blocked, says Mushotzky. The astronomers are of the opinion that 20 percent of X-ray radiations constitute these objects based on the previous observations. However, these observations, based upon Chandra observatory, were unable to identify the nature of all these sources. Discovery of these new AGNs is an important step towards understanding the evolution of universe as black holes are thought to play important role in this process. ‘You can’t understand the universe without understanding giant black holes and what they’re doing. To complete our understanding we must have an unbiased sample’, says Tueller.

Google is reaching everywhere from Earth to Sky. Now the California web giant, Google is casting its net across the rest of the universe as well. Google has launched a new service, called Sky within Google Earth , which will allow users to view the skies as seen from Earth. Google Sky allows users to fly around and zoom in and expose detailed imagery of around 100 million galaxies and 200 million stars. US based Google engineers have developed the Google’s new feature Sky in cooperation with scientific group, including the UK Astronomy Technology Centre and the Anglo-Australian Observatory in New South Wales. Users can access Google Sky by clicking "Switch to Sky" from the "View" menu, or click the Sky button on the Google Earth toolbar. The "steer," "drag, "zoom" and "search" navigation buttons work just like the terrestrial versions. Users can also save their favorite planets, stars, galaxies, and extraterrestrial hot spots. Like Google earth, users can zoom in to see their points of interest, including Taurus, Scorpio or Sagittarius, or the black hole NGC 5128. Users can complete the subject by adding photographs and information instead of clicking on third party pop-ups.

Black holes have baffled scientists for a long time. The dense mass of the dead star that has is dense enough to gobble huge planets and stars. Recently astronomers have discovered a powerful black hole blasting a galaxy. Astronomers have earlier witnessed collision between galaxies but this is the first time they have seen collision of such large scale. In a recent discovery a large galaxy called the ‘death star galaxy’ has a jet of high energy particles and magnetic fields emanating from the back hole at its centre that is gobbling a smaller galaxy standing close to it. Black holes are present at the centre of most galaxies. Some galaxies eject powerful jets from the vicinity of the black holes. A Black hole is a hypothetical region of space possessing a gravitational field so intense that no matter or radiation can escape from it. Such regions are said to form when a star collapses, having used all its nuclear fuel. Smaller stars create supernova explosions when they die leaving neutron star; it is the more massive stars that are believed to create black holes. Though the current discovery shows the black hole feeding on the smaller galaxy causing its death, the strangest fact of such cosmic event is that eventually after the destruction is complete the massive influx of energy and radiation into the smaller galaxy will create new stars and planet – a Sphinx-like rise from the ashes of death. The problem of detecting black holes is that they are unable to emit or reflect any radiation. Earth is safe from the havoc causing actions of black holes. If our solar system came in the line of fire of any jet emanating black hole then the ozone layer of the earth’s atmosphere would be destroyed and life on the planet would face mass extinction. How safe is our planet from the scourges of the black holes. Astronomers believe there are two such beasts near the centre of our galaxy, the Milky Way. Source