The comet ISON is coming this year and it promises to put on the greatest sky show in the history of the human race.
If you haven't heard about this spectacular celestial visitor, you will in the coming months. Due to appear in the skies of the Northern Hemisphere during late November 2013 and into early December, the comet (officially designated as Comet C/2012 S1) spotted by two amateur Russian astronomers, Artyom Novichonok and Vitali Nevski of the International Scientific Optical Network (ISON), in September 2012 may turn out to be the most spectacular visitor to grace the skies since humans first took shelter in caves.
Some grinning astronomers predict ISON may become so brilliant it could shine 13 times brighter than the full Moon. If it does become that bright it will be visible both day and night.
The path, size and orbit of a comet are the primary guidelines for predicting just how bright a comet might become as it approaches the sun and whips about it before heading back out of the solar system. Every indicator promises ISON will deliver a heavenly show.
Scientists calculate the comet is about two-miles wide.
Excited astronomers explain that despite its current distance from the sun the comet is already far brighter than most. Add to that its orbit: scientists calculate that ISON is—almost eerily—on the same trajectory as one of the most amazing comets ever recorded in human history known as the Great Comet of 1680.
Another comet, that almost caused the end of the world, brushed by Earth in 1863. Mexican astronomer José Banilla, recorded evidence of the comet that modern day astronomers calculated came within fractions of a second from slamming into Earth and killing off humanity. It missed by a mere 335 miles.
Although Comet ISON will pass Earth at a very safe distance, it is sure to cause a major stir as humans have a history of reacting in terror to the ghostly visitors that appear in the sky and no human alive has ever seen anything like the comet approaching.
Before ISON arrives another brilliant comet will appear in the skies during March. That comet will probably cause a lot of buzz, and if it was the only comet in 2013 it would be long remembered as it's predicted to be a brilliant comet in its own right.
But eight months later the monster of all comets will arrive and the comparison between the two will be like a candle to a spotlight.
Each month ISON will become more visible
During the first quarter of 2013 the comet will be visible to those amateur astronomers with at least a 10-inch Newtonian telescope. Even the most powerful field binoculars won't be able to resolve the image of the comet. But many local planetariums with larger telescopes will be able to track it. A call to one of the planetariums may provide interested comet-watchers with an early peek of ISON. A comprehensive list of planetariums in the U.S. is available here.
From then on, each week that passes the comet will become measurably brighter.
By September 2013 ISON will be visible with a small telescope or a pair of optical quality binoculars. By later September or the early part of October ISON will be visible to the naked eye as a hazy blob of light in the night sky.
NASA's MRO to shoot ISON
When October 2013 arrives NASA scientists at the Jet Propulsion Laboratory in Pasadena, California will attempt a first. Realigning the optics aboard the Mars Reconnaissance Orbiter, the JPL crew will attempt a little long distance photography: snapping photos of the spectacular comet as it passes the orbit of Mars.
According to Marshall Connolly at Catholic Online, ISON will be just one million miles from the surface of the sun at its closest approach. No one knows if the comet will survive its brush with the solar surface. Some do not survive such close encounters.
But, "Assuming it survives," writes Connolly, "it will likely become extraordinarily bright and visible, even in the daytime sky. It's chances are fair, as comets often survive even closer approaches than this. After approaching the sun, the comet will next pass near us, just 40 million miles from Earth.
"Comet ISON's odds cannot be predicted since this is almost certainly the first time it has entered the inner solar system from its likely origin in the Oort cloud. The Oort cloud is a halo of comets believed to exist at the distant edge of the solar system, remnants of creation. Scientists believe that occasional gravitational perturbations can knock these comets out of their distant orbits and send them falling towards the sun."
ISON's closing act
Once ISON is one it's way back out of the solar system the comet will leave behind a spectacular farewell. Scientists studying its trajectory predict that ISON will leave a wide trail of dust, rock and ice particles behind it.
When Earth passes through Ison's orbit between January 14 to 15 in 2014, a record-breaking meteor shower is possible. Depending on the location and the swath of debris that Earth passes through, thousands of shooting stars per hour may be visible.