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Waiting for Comet ISON

So now we have three hypotheses for the COMET ISON as it approaches and passes the perihelion over the next 28 days (Nov 28th is the date) : 

  • NASA Frozen Ice : predicts extreme temperature and pressure might (50-50) cause disintegration of the shell and evaporation of the core. Good news : the 2 tails do not intersect earth's orbit even after any explosion.
  • Hoyle Wickramasinghe's Panspermia Model : predicts "seeds of life" carried in comet. Might be possible to test in stratosphere when earth is closest to ISON trajectory in late January. BUT if COMA does "explode" it is likely any matter is vaporized.
  • James McCanney's Plasma Discharge Comet Theory : predicts serious effects on the sun, the earth's magnetic field and the sun's own solar wind. Potential effects on earth/satellite communication is unknown but worrisome.

Question from BCMETEORS.NET to STScI OPOPlease could you comment on the best time amateur meteor watchers should look for meteors from ISON’s dust tail.

Answer :  Hello Bill: One study indicates that there will be very little chance of meteor activity related to Comet ISON:  http://arxiv.org/abs/1310.3171

Nevertheless, it looks to me like possibly the best chance to look for any meteor activity would be in mid-January, when the Earth passes "near" where the comet had travelled earlier in its orbit (NB the earth never passes directly through the path of the comet).  These simulations nicely show the path of the comet and the planets through the Solar System.  Zolt Levay STScI OPO  http://svs.gsfc.nasa.gov/vis/a010000/a011200/a011222/

Question : Hi Zolt : last quick question : The missing possibility (at least from the abstract) is what would be the affects of  disintegration (estimated at 50%) . Depending on how this might occur? I assume it would be caused by  gravitational stress (+ heat) on the shell. If the shell shatters the resulting “explosion” surely would be similar to the Chelyabinsk explosion (even though this was caused by air friction and heat). When this occurs would not energy (and particles – water etc)  dissipate initially spherically and then conically? Or away from the sun? or what?

Answer : Hi Bill, I'm not an expert in this area, so I can't comment in detail on the mechanics of exploding comets or meteors.  However, yes I suppose that if the comet disintegrates, I suppose the material would drift apart and be spread over a larger volume, whether its explosive or more gradual.  I wouldn't be able to estimate how much larger.  

If the comet does disintegrate as it approaches the Sun, those smaller pieces would heat more quickly and be much more likely to completely dissipate.  I guess that material has to go somewhere, but much of it will totally vaporize -- becoming gas instead of pebbles -- and be spread over an extremely large volume at very low density, and with little chance of intersecting with anything else in the Solar System.  Seems a little anticlimactic I admit.  Nevertheless, it certainly doesn't hurt to look for extra meteors. 

Zolt, STScI OPO

(Sen) - One of the most eagerly awaited comets in history is livening up as it heads for its rendezvous with the Sun later this year.

Comet ISON has already been monitored by the Hubble Space Telescope and the Swift satellite as it races in between the orbits of Jupiter and Mars. Now another orbiting observatory, NASA’s Spitzer Space Telescope, has taken its own close-ups.

Images newly released show the comet, officially labelled C/2012 S1, as it appeared with Spitzer’s infrared array camera on 13 June when it lay about 500 million km from the Sun. It was clearly already fizzing with activity.

The picture on the left, taken at a wavelength of 3.6 microns, shows a tail of fine rocky dust being ejected from the comet’s head and being blown away by the pressure of the solar wind.

UK astronomy populariser Stuart Atkinson has setup a blog, Waiting for ISON, with observing advice and star maps to help people view the comet. He told Sen: “These are fascinating observations from Spitzer. We’re all crossing our fingers that this is a good sign and that ISON will become very active as it approaches and rounds the Sun.

“Hopefully it means ISON will captivate us all in early December, but of course everyone should just try and stay calm and not get too carried away. ISON might dazzle and delight us, or disappoint and depress us, it’s too early to say yet, no matter what anyone tells you.

“It’s often said that comets are like cats but I think they’re more like politicians: sometimes they promise us the world at first, to get our attention, and then let us down! But let’s hope for the best!”

The comet has an orbit that is close to a parabola, which suggests it may be on its first journey into the inner Solar System from the Oort cloud of icy bodies that is thought to surround it. It has the consistency of a dirty snowball, being made up of dust and gases such as water, ammonia, methane and carbon dioxide left over from the formation of the planets 4.5 billion years ago.