Thiscomet appears very promising and we are long over due for aspectacular event. The comment here is that the tail is formed fromcomplex molecules. That is the accepted explanation. It is myconjecture that the bulk of the dust is in the form of elementalcarbon which naturally charges up as it passes through the solarflux. That acquired charge naturally produces a huge halo.
Thisone is in the high end of probability so sit back for a neat ride. It is too bad we cannot get something up there to intercept it andrecover samples.
Inthe meantime it is time to put it on our watch list.
WillThis Be The Comet Of The Century?
CalebA. Scharf | February6, 2013
http://blogs.scientificamerican.com/life-unbounded/2013/02/06/will-this-be-the-comet-of-the-century/
NASA’s DeepImpact probe hascaptured images of Comet C/2012 S1 (ISON), as it moves past theorbital distance of Jupiter on what may be its first trip inwards tothe Sun, and possibly a spectacular show.
Cometsare notoriously fickle beasts. Chunks of primordial rock, dust, andvolatile ices that formed some 4.5 billion years ago around ourfledgling sun, they can occasionally fly on Icarus-like orbits thatbring them to the inner solar system.Increasingsolar irradiation warms their surfaces and sublimates components likesolid water and carbon dioxide – creating great tails of reflectinggas and glowing ions, along with streams of dusty carbon compoundsand silicates.Someof these bodies are on long elliptical orbits that bring them backagain and again to the inner solar sanctum. Halley’s comet forexample has an approximately 75 year long orbit, and its glowingpassage has been recorded by humans some 29 times and probably seenmany more.Othersfall inwards from a still mysterious region beyond all known majorand minor planets – the Oort cloud. This detritus from our solarsystem’s youth exists somewhere between about 2,000 and 50,000times further from the Sun than the Earth is, perhaps even stretchingto a light year from us.It’sthese long-period comets (each of which may or may not ever visit usagain) that have the greatest potential to light up the brightest asthey fall inwards, since they may be essentially pristine, theirvolatiles ripe for a spot of solar heating.CometC/2012 s1, or ISON (International Scientific OpticalNetwork) wasdiscoveredinSeptember 2012 by Russian astronomers Vitali Nevski and ArtyomNovichonok. It’s an extremely promising candidate for becoming atruly spectacular object both before and after its closest solarapproach of 800,000 miles on November 28th 2013.
Ofcourse we’ve all heard this before. Over the years many newlyspotted cometary bodies have been touted as ‘the next great comet,’only to sputter and fizzle to something less than impressive. Theproblem is that the precise composition and physical structure of anycometary chunk is hard to predict, as is its reaction to increasingtemperatures. No two cometary bodies are the same.Butwe keep hoping, because a bright comet is something amazing, and overcenturies and millennia there have been some truly great ones. Lastcentury, in 1910, the “Great January Comet of 1910″ (C/1910 A1)was visible during the day and lasted a couple of months. The GreatComet of 1882 became bright enough in September of that year (aroundits closest approach to the Sun) to be visible in the sky adjacent tothe Sun. And there have been many more witnessed across humanhistory.
CometISON is looking promising. On January 17th NASA’s Deep Impactspacecraft (the surviving mother craft of the Deep Impact mission tocollide a copper impact probe with comet 9P/Tempel – which it didsuccessfully in 2005) was able to snap a series of images of ISONfrom a distance of about 493 million miles, as the cometary bodyapproaches about 4.8 Earth orbital radii (astronomical units) fromthe Sun.Hereis a time lapse movie of these pictures, if you look carefully you’llsee that already there are signs of a glowing tail some 40,000 mileslong. It’s possible that ISON will not disappoint.
Allcomets present a smorgasbord of scientific data. Their tails ofparticles and dust providing insights to the streaming solar wind andinterplanetary magnetic fields, and their contents providing insightto the rich chemistry of our proto-planetary system more than 4billion years ago.Oortcloud objects are also intriguing because they may represent materialstolen from our stellar siblings. A long-standing problem has beenthat the number of long-period comets seems rather high compared toour expectations for the population density of an Oort cloud formedfrom icy material flung outwards during planet formation.Infact the numbers are amazingly discrepant. While most models of solarsystem formation suggest there could be some 6 billion icy chunks inthe Oort cloud, the comet counts indicate a population of about 400billion. Quite a conundrum.In2010 HalLevison and colleagues usedcomputer simulations to demonstrate that this apparent over-richnessof cometary bodies could be explained if our Sun had emerged from itsstellar birth cluster with more than its fair share of these outerpieces. In other words, dynamical pulling and shoving with its sistersuns resulted in the acquisition of a vast number of alien cometarybodies.
Sonot only might ISON be a bright and beautiful creature as itapproaches the Sun, it could be truly a visitor from the stars.Aboutthe Author: CalebScharf is the director of Columbia University's multidisciplinaryAstrobiology Center. He has worked in the fields of observationalcosmology, X-ray astronomy, and more recently exoplanetary science.His latest book is 'Gravity's Engines: How Bubble-Blowing Black HolesRule Galaxies, Stars, and Life in the Cosmos', and he is working on'The Copernicus Complex' (both from Scientific American / Farrar,Straus and Giroux.) Follow on Twitter @caleb_scharf.
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