Comet ISON: 12 cool facts.

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Over the years we’ve had some pretty amazing comets swing by our planet. I remember the ones I’ve seen myself: HyakutakeHale-BoppHolmesPan-STARRS,McNaught… they were all beautiful and amazing sights.

Now we have C/2012 S1 (ISON) passing our way, and it’s certainly grabbing attention. It’s brightened substantially in just the past few days, so now’s the time to see it! The pictures people are taking are phenomenal, and there’s plenty of science pouring in as well.

Everyone loves a good picture, of course, but comets are amazing well beyond just their stunning beauty. So I figured I’d take this opportunity to tell you a few things about this comet, a handful of facts to nourish the part of your brain seeking out wonder. Keep these in mind while you’re gawking at the gorgeous pictures.

1) ISON is a n00b.

Some comets are on long, elliptical orbits dropping them in to the inner solar system before sailing them back out to the depths of space. There, they slow, stop, then fall once again back into the warmth and light. Comet Halley, for example, is on a 75-year orbit that takes it out past Neptune.

But some are more extreme. If they get an extra kick on their way in — perhaps from a collision, or a boost by a planet’s gravity — their elliptical orbit gets turned into an open-ended hyperbola: they have more than enough energy to leave the solar system forever. Once they’re gone, they’re gone.

Written By: Phil Plait
continue to source article at slate.com

7 COMMENTS

  1. @OP – But some are more extreme. If they get an extra kick on their way in — perhaps from a collision, or a boost by a planet’s gravity — their elliptical orbit gets turned into an open-ended hyperbola: they have more than enough energy to leave the solar system forever. Once they’re gone, they’re gone.

    Yep! It’s been happening for billions of years as the Solar-System evolved into its present form and present orbits. ;-

    http://astroclock2010.wordpress.com/cosmic-timeline-17/

    the nebular hypothesis,
    After the formation of the Solar System, the orbits of all the giant planets continued to change slowly, influenced by their interaction with large number of remaining planetesimals. After 500–600 million years (about 4 billion years ago) Jupiter and Saturn fell into a 2:1 resonance; Saturn orbited the Sun once for every two Jupiter orbits. This resonance created a gravitational push against the outer planets, causing Neptune to surge past Uranus and plough into the ancient Kuiper belt.

    The planets scattered the majority of the small icy bodies inwards, while themselves moving outwards. These planetesimals then scattered off the next planet they encountered in a similar manner, moving the planets’ orbits outwards while they moved inwards. This process continued until the planetesimals interacted with Jupiter, whose immense gravity sent them into highly elliptical orbits or even ejected them outright from the Solar System. This caused Jupiter to move slightly inward. Those objects scattered by Jupiter into highly elliptical orbits formed the Oort cloud; those objects scattered to a lesser degree by the changing orbit of Neptune formed the current Kuiper belt and scattered disc.

  2. I was living on Quadra Island when Hale Bopp visited. At night there was no ambient light. You could not see your hand in front of your face. What a magical sight the comet was. If any of you get to go to a no-light place to view this new comet, I hope you take it.

    • In reply to #3 by Roedy:

      I was living on Quadra Island when Hale Bopp visited. At night there was no ambient light. You could not see your hand in front of your face. What a magical sight the comet was. If any of you get to go to a no-light place to view this new comet, I hope you take it.

      Ah, but Hale Bopp was a very big comet. I was able to see it from the window of a taxi driving along the Westside Highway in Manhattan. The lack of light over the Hudson river made it possible to see it, and when I pointed it out to the taxi-driver, he was astonished. He wasn’t even sure what a comet was, so I explained. This time around, I’m stuck in Brussels, in the most illuminated country in Europe, so I’m hoping for a) clear weather and b) that ISON survives it’s solar drive-by so that i can see it from an open field.
      Wish I knew the constellations better so I”d know where to look for it.

  3. The Horizon special on BBC2 stated more than once that Ison had been knocked out of its original orbit due to the gravitational effect of a passing star. Surely this is pure speculation?

    • In reply to #5 by BroughtyBoy:

      The Horizon special on BBC2 stated more than once that Ison had been knocked out of its original orbit due to the gravitational effect of a passing star. Surely this is pure speculation?

      I can’t say for this particular instance, but it is certainly possible. If it has a measured velocity which will allow it to escape the Solar-System, it must have been shunted by some gravitational effect (or collision). Either a large object at a distance or a smaller one closer to it.

      Some of the outer comets in the Oort Cloud (http://www.space.com/16401-oort-cloud-the-outer-solar-system-s-icy-shell.html) have orbits which go a quarter of the way to Centauri or more.

      http://www.noao.edu/education/peppercorn/pcmain.html
      The solar system does not really end with Pluto. Besides the planets, there is a thin haze of dust (some of it bunched into comets). Any of this dust that is nearer to the Sun than to any other star may be in the gravitational hold of the Sun and so counts as part of the solar system. So the outermost of such dust may be half way to the nearest star.

  4. Any one else here wondering whether the Christian Crazy Brigade will pick up on the fact that this new ‘star of Bethlehem’ makes its closest approach to Earth on Christmas Day-Boxing Day?

    You can just imagine the websites that will spring up… maybe I should start one for a laugh… :-)

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