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Subject: Comet Memories...
Time: 11:33:00 AM EST
Author: stuartatk
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Just when you think you’ve seen everything weird the night sky has to offer, just when you think it can’t surprise you any more, just when you’re starting to believe that nothing ‘up there’ could make your jaw drop any longer, the universe jumps out at you from around a corner, shouts “boo!” in your ear and runs away giggling.
Which is exactly what it’s done with Comet Holmes.
Above: Comet Holmes as photographed by Eddington AS astrophotographer Ken Hough.
Last night I saw the comet for the sixth time, from the brightly-lit grounds of the grand old museum in Kendal where my astronomical society holds its monthly meetings. Standing outside in the chilly night air, sipping from my half-time cup of tea and nibbling a deliciously crumbly choccie biccie I looked up and saw the comet shining softly above the houses, churches and pubs of my town; dimmed both by the light pollution of Kendal and by the haze left lingering in the air after the “shock and awe” fireworks display that had lit up the heavens above my town’s ruined castle, the comet was still clearly visible to the naked eye, glowing softly among the ice blue stars of Perseus.
Half a dozen other members of the Eddington Astronomical Society were there looking up at the comet too, shielding their eyes from the glare of the floodlights and security lights with raised hands, seeking out “the comet” they had heard so much about and that I’d shown them dozens of amazing pictures of during my News Roundup at the start of the night’s meeting. Having found it, or having had it pointed outto them, a few gave a disappointed “humph!” and walked back inside, grumbling and mumbling variations along the theme of “Is that kit? Is that what all the fuss is about?” but most of my members looked at it quietly and smiled, pleased they’d seen ‘the real thing’ after gasping at all the breathtaking, stacked-and stretched-and-enhanced-to-within-an-inch-of-their-lives image culled from the galleries at Spaceweather.com and others takenby the more experienced astrophotographers in our group. Me? For once I was happy to just stand outside on my own, away from everyone else, looking up at the tiny snow globe of “the Exploding Comet” shining serenely above the Auld Grey Town of Kendal and ponder what was going on out there, so far, far away, in the Deep Dark between Mars and Jupiter and far above the crowded plane of the Solar System…
“What happened to you, little one?” I wondered, lifting up my trusty binoculars to bring the comet into sharper, clearer focus. Magnified ten times it looked even more like a ball of smoke, a misty grey powdery smear beside the diamond chip sharp stars central Perseus. It looked so peaceful, so quiet, like a dandelion head drifting serenely through the void between the worlds, but I knew that Holmes’ hidden icy nucleus had been the victim of some unbelievably violent and unusual cosmic catastrophe.
New images showed pieces of… something… moving away from the main nucleus, trailing their own misty tails – or rather pushing them out ahead of them, as Holmes is now moving away from the Sun back out into space, towards the outer worlds. The nature of those pieces is hardly a mystery worthy of the comet’s detective namesake – it’s elementary, they must be pieces of the comet, fragments that are drifting further away from the nucleus each day - but what made those pieces break off in the first place? Ah, that’s the question Watson…
Either the comet has suffered some dramatic structural failure, or it has had a shattering collision with something else Out There. If the former explanation for its sudden increase in brightness is correct – a million fold increase in brightness in a matter of hours – then perhaps a section of its icy crust collapsed or simply sublimed away, exposing rich deposits of virgin nucleus material that, suddenly exposed to the heat and light of the Sun, flared and flashed into life, vomiting fresh dust and gas out into space like the wounded Apollo 13 command module spewed out its occupants’ precious oxygen supply. That event resulted in a spherical debris shell enveloping the comet, a shell that expanded and grew into a wreath of particles that made it shine in our sky a million times brighter than it had been mere hours before.
Now, that would have been amazing enough.
But the alternative is even more amazing: as Comet Holmes retreated from the Sun, turning its icy back on Sol and its belly towards the butter cream-and-caramel coloured globe of Jupiter, it hit something, or something hit it, violently, catastrophically, causing an explosion that blasted plates and slabs of the nucleus off it and out into space, surrounding the comet in that slowly expanding cocoon-like shell which we have all been staring at this past couple of weeks.
That scenario is supported by the previously mentioned images showing pieces of the comet falling away from it, developing their own tails, so that’s the “Smoking Gun” in this cosmic game of Cluedo. But what was the bullet that shot out of that gun barrel? A small asteroid that just happened to be in the comet’s path, a piece of rocky debris that was simply in the wrong place at the wrong time? Or was it another comet? That would be an incredible coincidence, to have another comet barrelling along in an orbit that sent it cutting suicidally across Holmes path before crashing into it – a gazillionquillion-to-one chance really – in a cosmic kamikaze dive, but of course we may never know if that’s what actually happened.
What we do know is that the comet is quite unlike anything we’ve ever seen – well, unlike anything I’ve ever seen before, at least, and I’ve been a Comet Watcher for a loooooong time, for as long as I’ve been looking at the sky in fact.
In 1983, as an 18 year old novice stargazer I dragged my poor, long-suffering but always supportive mum out into the countryside to let me see Comet IRAS-Araki-Alcock from a dark country lane away from my town’s streetlights. It was a remarkable comet, no tail, just a round globe of light, easily visible to the naked eye, that filled the bowl of the Little Dipper as it sped through it, That comet, I recall, came so close to us it was possible to see it moving against the starry backdrop through a telescope eyepiece over the course of a few minutes…
A couple of years later – ironically, on Bonfire Night in 1985, in a sky full of haze and smoke from fireworks displays - I saw Halley’s Comet for the first time, after all those years of reading about it in the astronomy books! To be honest it was a bit of a damp squib after all the hype and build-up, and my favourite memory of Halley is of showing it to an old woman who was determined to see it again after being shown it by her father in 1910 when she was a young girl. “He said I’d never see it again,” she smiled, tears rolling down her face, “and you just helped me prove him wrong, the smug, know-it-all old b*****d, so thank you!”
Then Hyakutake appeared in the sky, with that outrageously bright head and impossibly, ridiculously long tail. I remember as if it were yesterday standing in a dark country field, staring up in shocked disbelieving silence at Hyakutake’s tail stretching across the sky, right across the sky, like an aeroplane’s vapour trail…
Soon after Hyakutake it was Comet Hale-Bopp that had me staring slack-jawed at the sky. Because of its beautiful twin tails, it brightness and its long period of visibility- which coincided with a very rare stretch of clear nights here in the UK - Hale-Bopp was The Comet, the one everyone remembers to this day. I will never forget standing in the centre of an ancient Lake District stone circle –older than Stonehenge – and watching the comet rising up from behind one of the mountains that surrounds it. The tails rose first, twin faint search-beams jabbing into thestarry sky, followed by the bright head. Leaning against the old, shockingly-cold standing stones of Castlerigg stone circle my gritty-eyed observing partner and I could only gape at it in silence and drinkin the view…
More recently Comet McNaught graced our skies. Well, when I say “our skies” I mean “the skies of those lucky ***** southern hemisphere observers”, because from up here in the north my view was ruined by not just the comet’s low altitude and proximity to the sun but by the god awful weather at the time too. I managed just four glimpses of the comet before it plunged behind my horizon and swept into the southern sky, trailing that strutting dandy of a peacock tail behind it as it danced through the constellations of the southern skies, and my best view was actually while it was raining on me! I caught a glimpse of the comet in my binoculars through a ripped tear in charcoal black clouds that soaked me with rain even as I watched McNaught drop out of sight. Of course, it was worth it.
And now Comet Holmes has me transfixed. From my own backyard, from the grounds of that crumbling castle and from the shadows of a mighty floodlit Museum I’ve stared at it half a dozen times now, with my naked eye, my binoculars, and my humble but trusty 4.5” reflector too, and I have never, ever seen anything like it. It’s like a ghost, a phantom, wafting through the sky, eerie but beautiful at the same time. And watching the streaming video footage of the daring space walk to repair the tear in the International Space Station’s torn solar array I couldn’t help wondering if those two astronauts, as busy as they were, stole a moment to look at the comet too…
There will be other comets in the future, I’m sure - brighter ones, bigger ones, more dramatic looking ones - but there’ll always be a special place in my heart for “The Exploding Comet” that graced my Cumbrian Skies in the dying months of 2007.
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11/7/07 11:54 AM