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Thread: comet elenin collision probability

  1. #1
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    comet elenin collision probability

    I know comet elenin will only approach earth within about a Venusian distance which isn't close, in Oct. 2011, but with the comet near the ecliptic, what are the chances we'll have a dynamic "meteor storm" here on earth similar to the one we had in 1966 (I remember that one, but can't remember if it was Leonids or Lyrids).

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    That would be pretty awesome I have to say I have never seen a meteor shower in my life even the latest Leonids one that happened a few days ago

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    Quote Originally Posted by emmylou View Post
    That would be pretty awesome I have to say I have never seen a meteor shower in my life even the latest Leonids one that happened a few days ago
    Meteor showers are very common, and I once spotted the Perseids in August and counted 60 meteors I saw in a 1 hour period. But you do have to go out after midnight, and a very dark , moonless sky, with little clouds, so it's a little tough to see sometimes.

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    I would suggest you drop Centaur a PM and ask he take a look at this thread. He is very interested and very good at observational astronomy, and has posted threads on both meteor showers and on the comet. I don't think he takes a look too often at Q&A, so he might not have seen this thread.
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    This is an interesting question, so I thought I'd set it up in Gravity Simulator to see if there's any chance of a meteor shower or storm from debris shed by Elenin at perihelion. Elenin crosses Earth's orbit on October 19, and Earth crosses Elenin's orbit 12 days later on October 31. Earth passes 4.6 million km below Elenin's orbital path. So any debris shed by Elenin at perihelion will have to have enough velocity to fall 12 days behind Elenin and travel 4.6 million km vertically. The vertical part is easy. It's got about 50 days from perihelion to the point Earth crosses its path. So it needs a velocity of about 1 km/s.

    So I created 100 particles exploding from Elenin in random directions, moving away at 1 km/s. But this wasn't enough velocity to create the 12 day lag. So I pumped up the velocity. It took a velocity of 11 km/s for any particles shed from Elenin to come close to Earth. I don't know anything about the dynamics of the surfaces of comets that get superheated, but I would guess that this too high to be realistic.

    The first image shows a cloud of particles fleeing Elenin as it gets superheated from the Sun at perihelion. The particles are escaping in random 3D directions at velocities of 11.5 km/s.


    The next image shows Earth (blue dot) orbit of the Moon (gray dot to the left of Earth), Elenin (orange), and the debris shed by Elenin (maroon) as the debris cloud encompasses the Earth/Moon system.

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    Thanks for the gravity simulation. Looks like some debris will hit earth's atmosphere.

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    I was guessing Earth wouldn't get any debris. For anything to get to us, it needs to be ejected from Elenin at 11 km/s. I'm sure there's going to be lots of popping and fizzing when this comet comes closer to the Sun than Mercury, but I doubt any particles will leave Elenin with that high of a velocity.

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    Now that Elenin has broken up, is there any greater chance of a meteor shower or storm in future years as the debris drifts? If so when and how severe?

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    Quote Originally Posted by gdaniels99 View Post
    Now that Elenin has broken up, is there any greater chance of a meteor shower or storm in future years as the debris drifts? If so when and how severe?
    The debris is following similar orbits to the original comet did so its not going to be coming back into the inner solar system for the next 600,000 years on average and will has dispersed a lot over that time so won't produce much of a show much less any danger to Earth.

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    Not to mention the fact that, in order for a meteor shower to be seen on Earth, the path of the comet must cross Earth's orbit with very little (in astronomical terms) vertical displacement. I have not heard that this is the case with Comet Elenin.

    Fred
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    Earth's sole legacy will be a very slight increase (0.01%) of the solar metallicity.

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    And it was rather small as comets go, so not a lot of debris available.

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    Quote Originally Posted by gdaniels99 View Post
    Now that Elenin has broken up, is there any greater chance of a meteor shower or storm in future years as the debris drifts? If so when and how severe?
    So to sum up, No, Never, and Nothing at all.

    Fred
    Hey, you! "It's" with an apostrophe means "it is" or "it has." "Its" without an apostrophe means "belongs to it."

    "For shame, gentlemen, pack your evidence a little better against another time."
    -- John Dryden, "The Vindication of The Duke of Guise" 1684

    Earth's sole legacy will be a very slight increase (0.01%) of the solar metallicity.

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