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March 12, 2006, 9:35 PM CT

Workings Of Cosmic Clocks

Workings Of Cosmic Clocks
Astronomers using the 76-m Lovell radio telescope at the University of Manchester's Jodrell Bank Observatory have discovered a very strange pulsar that helps explain how pulsars act as 'cosmic clocks' and confirms theories put forward 37 years ago to explain the way in which pulsars emit their regular beams of radio waves - considered to be one of the hardest problems in astrophysics. Their research, now published in Science Express, reveals a pulsar that is only 'on' for part of the time. The strange pulsar is spinning about its own axis and slows down 50% faster when it is 'on' compared to when it is 'off'.

Pulsars are dense, highly magnetized neutron stars that are born in a violent explosion marking the death of massive stars. They act like cosmic lighthouses as they project a rotating beam of radio waves across the galaxy. Dr Michael Kramer explains, "Pulsars are a physicist's dream come true. They are made of the most extreme matter that we know of in the Universe, and their highly stable rotation makes them super-precise cosmic clocks - but, embarrassingly, we do not know how these clocks work. This discovery goes a long way towards solving this problem".

The research team, led by Dr Kramer, found a pulsar that is only periodically active. It appears as a normal pulsar for about a week and then "switches off" for about one month before emitting pulses again. The pulsar, called PSR B1931+24, is unique in this behaviour and affords astronomers an opportunity to compare its quiet and active phases. As it is quiet the majority of the time, it is difficult to detect, suggesting that there may be a number of other similar objects that have, so far, escaped detection.........

Posted by: Edwin      Permalink         Source

March 12, 2006, 3:19 PM CT

Moon

9251 posted a photo:

Moon

Moon with 45 magnify.Time: 6.10 pm 3.11.2006



moon rise over the gulf

deneb1800 posted a photo:

moon rise over the gulf



space

maginoiss posted a photo:

space

near moon edge



Permalink

Source:
  • Space.com



  • March 9, 2006, 11:25 PM CT

    GIOVE A Transmits Loud And Clear

    GIOVE A Transmits Loud And Clear
    After a successful launch on 28 December 2005, GIOVE A began transmitting navigation signals on 12 January 2006. Work is currently being performed to check the quality of these signals.

    In space, the success of a mission relies on the achievement of a series of milestones. This is particularly true for a pioneering mission such as GIOVE A, the first Galileo satellite, launched late last year under the European Space Agency's responsibility.

    Manufacture, launch, reaching final orbit and transmission of first signals: all these key steps were met by the satellite, which is now going to achieve its first goal, the filing for the frequencies allocated to Galileo by the International Telecommunication Union (ITU).

    After launch and platform commissioning, GIOVE A started signal transmission on 12 January and the quality of these signals is now being checked. This checking process is employing several facilities, including the Navigation Laboratory at ESA's European Space Research and Technology Centre (ESTEC), in the Netherlands, the ESA ground station at Redu, in Belgium, and the Rutherford Appleton Laboratory (RAL) Chilbolton Observatory in the United Kingdom.

    Chilbolton's 25 metre antenna makes it possible to acquire the signals from GIOVE A and verify they conform to the Galileo system's design specification. Each time the satellite is visible from Chilbolton, the large antenna is activated and tracks the satellite. GIOVE A orbits at an altitude of 23 260 kilometres, making a complete journey around the Earth in 14 hours and 22 minutes.........

    Posted by: Edwin      Permalink         Source


    March 8, 2006, 11:12 PM CT

    Trifid Nebula M20

    Trifid Nebula M20
    Central region of the Trifid Nebula (M20 in the Messier Catalogue) taken by the Gemini North 8-meter Telescope on Mauna Kea on the Big Island of Hawaii, June 5, 2002. Located in the constellation of Sagittarius, the beautiful nebula is a much-photographed, dynamic cloud of gas and dust where stars are being born. One of the massive stars at the nebula's center was born approximately 100,000 years ago. The nebula's distance from the Solar System remains in dispute, but it is generally agreed to be somewhere between 2,200 to 9,000 light years away.

    Source: Gemini Observatory........

    Posted by: Edwin      Permalink         Source

    March 7, 2006, 9:08 PM CT

    Eastern scarp of Olympus Mons

    These images, taken by the High Resolution Stereo Camera (HRSC) on board ESA's Mars Express spacecraft, show the eastern scarp of the Olympus Mons volcano on Mars.

    The HRSC obtained these images during orbit 1089 with a ground resolution of approximately 11 metres per pixel. The image is centred at 17.5° North and 230.5° East. The scarp is up to six kilometres high in places.

    Source

    March 7, 2006, 7:11 PM CT

    Shock Wave in Stephan's Quintet Galaxy

    Shock wave in Stephen's Quintet captured by Spitzer. Image credit: NASA/JPL-Caltech. Click to enlarge
    Sun, 05 Mar 2006 - This photograph, taken by the Spitzer space telescope and a ground-based telescope in Spain, shows the Stephan's Quintet galaxy cluster, with one of the largest shockwaves ever seen in the Universe. The green arc in the photograph is the point which two galaxies are colliding. There are actually 5 galaxies in this photograph, but two have been so beaten up, all that's left are their bright centers. The galaxies are located 300 million light-years away in the Pegasus constellation.


    Source

    March 4, 2006, 11:30 PM CT
    Astronomy Blog
    Mercury 0 - Venus
    Mercury 0 - Venus 1
    After reading Ian and Tom's entries about the chance of seeing Mercury in the evening sky on 1st March, I thought I might have a look. I'm near the west coast of New Zealand's north island and thought a 45km drive out to the coast would give me an uncluttered horizon. The weather had other ideas though. After being fine all afternoon, the cloud rolled in from the west just before sunset. To be even more annoying, it cleared away a few hours later having sat there long enough to make me miss Mercury. I did get a great view of the Milky Way though.

    This morning I was up bright and early as I was heading up to the very (technically not quite) top of New Zealand. I was lucky enough to see the planet Venus appearing very bright in the pre-dawn sky just before some more cloud rolled in. They don't call New Zealand the "land of the long white cloud" for nothing.

    The above headlines are from Astronomy Blog


    March 4, 2006, 9:08 PM CT

    Originate Of Titan's Methane

    Originate Of Titan's Methane
    Data from ESA's Huygens probe have been used to validate a new model of the evolution of Titan, Saturn's largest moon, showing that its methane supply may be locked away in a kind of methane-rich ice.

    The presence of methane in Titan's atmosphere is one of the major enigmas that the NASA/ESA/ASI Cassini-Huygens mission is trying to solve.

    Titan was revealed last year to have spectacular landscapes apparently carved by liquids. The Cassini-Huygens mission also showed that there is not after all a lot of liquid methane remaining on the moon's surface, and so it is not clear where the atmospheric methane gas comes from.

    Using the Cassini-Huygens findings, a model of Titan's evolution, focusing on the source of Titan's atmospheric methane, has been developed in a joint study by the University of Nantes, France, and the University of Arizona in Tucson, USA.

    "This model is in agreement with the observations made so far by both the Huygens probe that landed on Titan on 14 January 2005 and the remote sensing instruments on board the Cassini spacecraft," said Gabriel Tobie, of the Laboratoire de Planetologie et Geodynamique de Nantes, and lead author of an article in Nature.

    There is a difference between volcanism on Earth and 'cryovolcanism' on Titan. Volcanoes on Titan would involve ice melting and ice degassing, which is analogous to silicate volcanism on Earth, but with different materials.........

    Posted by: Edwin      Permalink         Source


    March 4, 2006, 8:59 PM CT

    Winning Postcards from Venus contest

    Winning Postcards from Venus contest Ominous Beauty by Tatianna Cwick, age 17, is the Grand Prize winner of the Postcards from Venus contest. Image Credit: Planetary Society
    Venus, as the goddess of beauty, has been celebrated in art and myth for millennia. Now, The Planetary Society and ESA celebrate the imagined rugged beauty of the planet's natural landscape with the winning entries in the 'Postcards from Venus' art contest in coordination with ESA's Venus Express mission, en route toward a rendezvous with Venus on 11 April 2006.

    Winners were selected in two age groups, youth and adult, with the Grand Prize winner being Tatianna Cwick, age 17, Cape Girardeau, Missouri, USA. Cwick has won a trip for herself and a guardian to the European Space Operations Centre (ESOC) in Darmstadt, Gera number of, when Venus Express arrives at its destination.

    "The title of my artwork is Ominous Beauty," said Cwick. "I think this captures the essence of the planet Venus, with its threatening volcanic environment and unique splendour".

    Cwick added that her father taught her most of what she knows about the planets, and that he suggested she enter the art contest because it 'could combine both of our interests - his love for space and my love for art.' .

    Yoo-Hong Sun, age 9, of South Korea was the first place winner in the youth category and Alejandra Gonzalez Quintana of Spain won first place for adults.

    The Venus Express mission will be the first spacecraft in more than ten years to visit our nearest planetary neighbour. Shrouded under a dense haze, Venus is a world steeped in mystery. Often called our 'sister planet', Venus is nearly identical to Earth in size and mass, yet its surface temperature is hotter than a kitchen oven because the thick atmosphere traps the Sun's heat.........

    Posted by: Edwin      Permalink         Source


    March 3, 2006, 6:52 AM CT

    Cosmic Dust Could Helpuncover The Origins Of Life

    Cosmic Dust Could Helpuncover The Origins Of Life Livermore researcher Zurong Dai uses a transmission electron microscope to capture the first close-up images of cometary dust collected by the Stardust spacecraft.
    A speck of dust smaller than the eye can see from a place where no humans have ventured may reveal clues to the birth of our solar system.

    By tailing a comet - serendipitously called Wild 2 - that was shooting material into space at 6.1 kilometers a second, NASA's Stardust spacecraft managed to pick up cometary and interplanetary dust particles that contain the very iron that is found in every human being's hemoglobin, and may provide hints to how life started on Earth.

    "It's dirt," said John Bradley, director of the Lawrence Livermore National Laboratory's Institute for Geophysics and Planetary Physics. "Basically, it's cosmic crud".

    But that cosmic crud found in deep space also makes up most of the contents of the human body. And it arrived on Earth from the Stardust spacecraft's seven-year mission just before 2 a.m. Sunday, Jan. 15, in the middle of a Utah desert. The sample return capsule (SRC) touched down at the correct velocity (10 mph), bounced five times, and then released the chute. The chute settled to the ground about 30 feet away.

    "The landing surface was smooth, dry mud-flat with a somewhat surreal appearance," Bradley said after the landing. "Everyone involved is elated but exhausted".

    For a perspective of the amount of dust gathered on the two-year mission, the Apollo moon missions brought back about 280 kilograms of material; on Stardust, less than a milligram of material was returned.........

    Posted by: Edwin      Permalink         Source


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