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Comet ISON: No sign of comet after pass around sun: Scientists

Discussion in 'Education & Research' started by Marqueur, Nov 29, 2013.

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  1. Marqueur

    Marqueur Peaceful Silence ELITE MEMBER

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    A comet's 5.5-million-year journey to the inner solar system apparently ended during a suicidal trip around the sun, leaving no trace of its once-bright tail or even remnants of rock and dust, scientists said on Thursday.

    The comet, known as ISON, was discovered last year when it was still far beyond Jupiter, raising the prospect of a spectacular naked-eye object by the time it graced Earth's skies in December.

    Comet ISON passed just 730,000 miles (1.2 million km) from the surface of the sun at 1.37pm EST/1837 GMT on Thursday. Astronomers used a fleet of solar telescopes to look for the comet after its slingshot around the sun, but to no avail.

    "I'm not seeing anything that emerged from the behind the solar disk. That could be the nail in the coffin," astrophysicist Karl Battams, with the Naval Research Laboratory in Washington, said during a live broadcast on Nasa TV."

    "It's sad that it seemed to have ended this way, but we're going to learn more about this comet," he added.

    At closest approach, the comet was moving faster than 217 miles per second(350 km per second) through the sun's atmosphere.

    At that distance, it reached temperatures of 5,000 degrees Fahrenheit(2,760 degrees Celsius) - hot enough to vaporize not just ices in the comet's body, but dust and rock as well.

    If the comet or any large fragments survived the close encounter with the sun, they would be visible to the naked eye in Earth's skies in a week or two.

    The comet was discovered last year by two amateur astronomers using Russia's International Scientific Optical Network, or ISON.

    Comets are believed to be frozen remains left over from the formation of the solar system some 4.5 billion years ago.

    The family of comets that ISON belongs to resides in the Oort Cloud, located about 10,000 times farther away from the sun than Earth, halfway to the next star.

    Occasionally, an Oort Cloud comet is gravitationally nudged out of the cloud by a passing star and into a flight path that millions of years later brings it into the inner solar system. Computer models show ISON was a first-time visitor.

    "I hope we see another one soon," said Dean Pesnell, project scientist for Nasa's Solar Dynamics Observatory.

    No sign of comet after pass around sun: Scientists - The Times of India

    :blink::hmm::dude:
     
  2. sangos

    sangos Lt. Colonel ELITE MEMBER

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    Comet ISON might not have disintegrated while flying past sun


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    Washington: Comet ISON may not have broken apart and evaporated in the fierce heat and crushing gravity of the sun before or during a close flyby Thursday.

    Well after many casual observers had given up on the comet's survival, updated pictures from the Solar and Heliospheric Observatory spacecraft-SOHO-showed what appeared to be a long trail of dust extending away from the sun along ISON's trajectory, brightening sharply toward its tip.

    Whether it was just a dust trail, or perhaps dust and larger fragments of ISON-or both-was not immediately clear.

    As several observers tweeted and re-tweeted: "It is now clear that Comet #ISON either survived or did not survive, or... maybe both. Hope that clarifies things."

    From the Solar and Heliospheric Observatory-SOHO-the trail of Comet ISON can be seen entering the frame at lower right, disappearing behind an occultation disk that blocks the sun's glare and exiting around the 11 o'clock position, brightening as if some portion of the comet's nucleus might have survived the encounter.

    Astronomers are not yet sure exactly what happened during ISON's close encounter with the sun.

    Matthew Knight, an astronomer at the Lowell Observatory in Flagstaff, Ariz., said in a telephone interview that it wasn't clear exactly what SOHO was observing.

    "Initially when something came out (after close approach), we thought this is just the dust trail and there's not much left, it's just going to fade away," he said.

    "And then images keep coming in and ... the last few, it seems pretty definitely like it's getting brighter. So we do not have a good answer as to what's going on.

    "My best guess right now, and it's really only an educated guess, is that there is something left, probably smaller fragments, because it still doesn't look like there's a nuclear condensation. Inbound, the leading edge was brighter. It doesn't look like that. It just looks to me like there are some smaller fragments that may just actually be disintegrating. They just took longer to do it," he said.

    But it's also possible, he said, there could be "still a substantial nucleus there and it's actually outgassing.

    Comet ISON might not have disintegrated while flying past sun
     
  3. sangos

    sangos Lt. Colonel ELITE MEMBER

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    Ison is like Hanuman who flew in and out of the sea monster's jaws and on to Lanka:woot:.

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