A Great Comet Coming?
We are due for a comet of the century. Is this it?
Last year brought a feast of celestial events that is difficult to beat. But the possibility of two naked-eye comets could elevate 2013 into a banner year for stargazing. Here are the highlights of what’s up in 2013.
By Alan Dyer
If we are very lucky, 2013 might end with a sight not seen in the sky for many decades: a comet bright enough to be easily observed in daylight. We have to look back to 1965, 1910, 1882, 1842, 1774 and 1680 to find the few comets that were as spectacular as Comet ISON has the potential to become.
But before reading further, please sign our legal disclaimer: Comet ISON could be stunning. Or it could be a dud. It might burst into brilliance as it rounds the Sun. Or it could fizzle and vaporize into nothing. Recent comets have done both, to the delight or disappointment of astronomy fans here on Earth. Remember, comets are agglomerations of ice and cosmic dust whose behaviour when heated can vary unpredictably.
Discovered on September 21, 2012, by astronomers with the International Scientific Optical Network (ISON), Comet C/2012 S1 is likely a first-time visitor from the distant Oort cloud. Its orbit will take it a searing 1.1 million kilometres—less than one solar diameter—from the Sun’s surface on November 28, 2013, its perihelion date. This makes it a member of the family of sungrazers that has produced some amazing comets in recorded history. Comet experts note that Comet ISON’s orbit is similar to the orbit of the Great Comet of 1680, which could be seen in daylight passing above the Sun. When it emerged into the evening sky, it shone at magnitude +2 (easily naked-eye, even in today’s urban light-polluted skies), with a tail 70 degrees long.
Whether Comet ISON performs as well remains to be seen. We won’t know until late 2013—not until after it rounds the Sun at the end of November—whether it lives up to the inevitable hype (and the idealized simulations shown here) or enters the history books as another celestial embarrassment for astronomers.
Some readers may remember a previous “comet of the century”: Comet Kohoutek was also to be a stunning sight around Christmas 1973. It fizzled, and very few people saw Kohoutek. It could happen again.
Click on photos to enlarge.
ALL IMAGES COURTESY STARRY NIGHT PRO PLUS™/SIMULATION CURRICULUM CORP.)