Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Hyperbolic Comet C-2012 S1 (ISON)

  1. Oct 21, 2013 #1
    What is happening with Hyperbolic Comet C-2012 S1 (ISON)? It is going to crash into the Sun at the end of Nov. Was it downgraded from a Comet? Here is a site that used to track it:


    I should be big in the night sky right now and soon it should be visible in the daylight.
    Last edited: Oct 21, 2013
  2. jcsd
  3. Oct 21, 2013 #2


    User Avatar
    2017 Award

    Staff: Mentor

    "used to track it"? The last observation is from today.
    With a magnitude of 13.5, it is too dim to be visible in daylight, and even at night you need a telescope. It reaches its perihelion in about a month, then we'll see what happens.
  4. Oct 21, 2013 #3


    User Avatar
    Science Advisor
    Gold Member

    The behavior of comets is about as predictable as a cat. At present, some doubt it will ever reach naked eye visibility, while others think it may become as bright as Venus. Those who think it will achieve 'comet of the century' status are rivaled in numbers by those who think it is the harbinger of doomsday.
  5. Nov 21, 2013 #4


    User Avatar
    Gold Member

    ISON is currently easily visible with binoculars, but will soon disappear in the sun's glare as it goes into perihelion.

    Assuming the comet doesn't disintegrate and the orbital mechanics don't change, planet Earth will begin a quick pass through the tail of C/2012 S1 (ISON) on about January 1, 2014. http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=c/2012 s1;orb=1;cov=0;log=0;cad=0#orb

    At this point, the nucleus will be about .449 AU (about 67 million kilometers, or 46 million miles) from Earth, and going away. The record length of a comet tail is 311 million kilometers.

    There are several flavors of comet tails. First is the dust tail, which is a very fine soot. Then there are the ion tails, which can be several kinds of charged particles.
    Last edited: Nov 21, 2013
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook