When Halley’s Comet appeared in 1910 the tail stretched almost a third of the way across the sky and the rumour mill went into overdrive.
The Yerkes Observatory announced there was cyanide in the tail of Halley’s Comet. The New York Times ran a story where a French astronomer claimed the cyanide “would impregnate the atmosphere and possibly snuff out all life on the planet.”
But nobody got sick. Drug manufacturers simply grew a little richer medicating the planet with ‘comet pills’ and industry sold a lot of gas masks that year.
It happened again in 2002 when we survived a so called planetary line-up with the pundits claiming the fabric of the Sun would be torn apart. Not to mention the famous ‘Mars Hoax’ from the same time alarming half the planet with claims Mars would be as big as the full Moon. And the fact Betelgeuse could go supernova tomorrow.
If these kind of theories are your bag, you’re in for a treat over the next three weeks.
On November 28, Comet C/2012 S1 ISON, otherwise known as “the Comet of the Century”, will reach perihelion – its closest point to the Sun – and shine brightly enough be visible with the naked eye.
ISON is not just another comet. It’s new, for starters, discovered just last year on September 21 by Vitali Nevski and Artyom Novichonok, two astronomers at the International Scientific Optical Network (ISON) near Kislovodsk, Russia using a 0.4 meter reflector telescope.
Depending on who you listen to, it’s going to be one of the most impressive sky events in the last 100 years, or the biggest fizzer in history.
Or it’s not actually a comet. Or it’s going to destroy us all.
Something about human psychology and sky events never fail to excite the imagination and bring out that intrinsic sense of wonder and imagination we carry with us from childhood.
It also brings out the unbalanced, the armchair astronomers and conspiracy theorists.
This time they needn’t bother – ISON is enough of an enigma in its own scientific right to make it at least as interesting as any crackpot theory.
Regardless, they all make the list. Here’s everything you need to know about the Comet of the Century:
1. It will be as bright as the full Moon.
Maybe. It will have to make a very rapid increase in size and brightness very soon for that to happen.
2. It’s supposed to be way brighter.
Early expectations were that it would gain in brightness even more as it got closer. It didn’t, confusing astronomers and disappointing amateur skywatchers who started muttering that ISON was a total dud. Comet observer Bruce Gary was first to snap the comet when it emerged from the glare of the Sun on August 12. When it faded like a solid body would, as opposed to a “fluffy comet”, he remarked: “I don’t know what’s going on with this comet!”
But they livened up again when it was realised early brightness measurements turned out to be inaccurate.
3. Doomsayers hope it will hit the Sun and send massive energy towards Earth, destroying all life.
Astronomers hope it survives its brush with destiny, heat, and gravity, at least long enough to light up our pre-dawn skies this December. Because it should be spectacular.
4. THERE’S SOMETHING TRAVELLING BEHIND IT.
The most popular mystery theory by far is that ISON is not actually a comet at all, but a spaceship headed for the Sun. There’s also “evidence” of up to two other crafts travelling with it. The UK’s Alien Disclosure Group say this blob has been snapped several times over the past couple of days in the same position behind ISON.
5. ISON could blast Earth with meteor showers if it breaks up.
Yes, it could.
6. But astronomers hope it doesn’t.
If ISON does survive its near solar encounter, it will become a stunning comet in the pre dawn skies leading up to the New Year. It’s predicted to make its closest approach to Earth on December 26, at a distance of 39.9 million miles.
7. It’s a “sungrazer”.
ISON will come to almost within a solar diameter of the Sun’s surface. This is extremely close, and the comet is classified as a sungrazer. Unfortunately, sungrazers rarely survive. Solar wind, radiation, and tidal forces on one hemisphere could tear ISON apart before perihelion.
8. Its trajectory makes it almost a twin of the Great Comet of 1680.
Also known as Kirch’s Comet, the Great Comet of 1680 was the first discovered by telescope and was famed for its extremely long tail.
Said to be visible even in daylight, the Great Comet reached a perihelion distance (closest approach to the Sun) of 0.006AU. ISON will approach at 0.012AU and both will approach to within ~0.4AU of Earth.
Both their paths through space are remarkably similar, according to isoncampaign.org:
The “argument of perihelion” is 351-degrees versus 360-degrees, and orbital inclination 61-degrees versus 60-degrees for Kirch and ISON, respectively
9. It’s in beautiful condition.
Because it’s ISON’s first visit to the inner Solar System, it’s in pristine condition with an almost intact and relatively thick layer of ice that will eventually melt as it approaches the Sun, causing the familiar tail we see on comets. In effect, it’s just gas sublimating from the comet’s surface.
10. It’s behaving weirdly.
ISON’s gas production rate has increased as it nears the Sun. That’s expected. What’s surprising astronomers is that its dust production rate has not. Carl Hergenrother of the Lunar and Planetary Laboratory in Arizona told Mother Nature Network: “I don’t really know what this means but something has to give, either the dust production picks up or the gas production slows down.”
11. The comet’s nucleus is unusually tiny.
Estimated at less than 2 kilometres in diameter, that’s small even through Hubble’s eagle eyes. Still, careful study of this image suggests the nucleus is almost certainly solid and still intact – the coma spreads out evenly from a single point, which we wouldn’t see if ISON were falling to pieces.
Comet observer John Bortle also told MNN: “I cannot recall any previous comet in my 50-plus years of comet observing looking quite like this … All I can say is I don’t like the odd look of it at this time.”
12. For now, ISON is still in one piece and still en route to the Sun.
If it survives, or breaks into two or three big pieces, then there should be a spectacular tail.
13. It’s probably going to usher in the New Year.
If it survives perhelion on November 28, ISON will make its closest approach to Earth on December 26, at a distance of 39.9 million miles. As it is low on the horizon, especially in the southern states, the best time to look is an hour and a half before local sunrise.
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