Ison - the comet of the century
Comet Ison could draw millions out into the dark to witness what could be the brightest comet seen in many generations
It was found as a blur on an electronic image of the night sky taken through a telescope at the Kislovodsk Observatory in Russia as part of a project to survey the sky looking for comets and asteroids – chunks of rock and ice that litter space. It was a frustrating night but about half an hour prior to the beginning of morning twilight, they noticed the sky was clearing and got the telescope and camera up and running to obtain some survey images in the constellations of Gemini and Cancer.
When the images were obtained Nevski loaded them into a computer program designed to detect asteroids and comets moving between images. He noticed a rather bright object with unusually slow movement, which he thought could only mean it was situated way beyond the orbit of Jupiter. But he couldn't tell if the object was a comet, so Novichonok booked time on a larger telescope to take another look. Less than a day later the new images revealed that Nevski and Novichonok had discovered a comet, which was named Comet Ison. These observations allowed its orbit to be calculated, and when astronomers did that they let out a collective "wow."
Comet Ison has taken millions of years to reach us travelling from the so-called Oort cloud – a reservoir of trillions and trillions of chunks of rock and ice, leftovers from the birth of the planets. It reaches out more than a light-year . In the Oort cloud the Sun is but a distant point of light whose feeble gravity is just enough to hold onto the cloud. Every once in a while a tiny tug of gravity, perhaps from a nearby star or wandering object, disturbs the cloud sending some of its comets out into interstellar space to be lost forever and a few are scattered sunward. Comet Ison is making its first, and perhaps only visit to us.
Ison's surface is very dark , darker than asphal with ice beneath the surface. It's a small body, a few tens of miles across, with a tiny pull of gravity. If you stood upon it you could leap 20 miles into space taking over a week to come down again, watching as the comet rotated beneath you. You could walk to the equator, kneel down and gather up handfuls of comet material to make snowballs, throw them in a direction against the comet's spin and watch them hang motionless in front of you. But it will not remain quiet on Comet Ison for the Sun's heat will bring it to life.
As Comet Ison heads back to deep space in 2k14 the sky above it would begin to clear as the dust and gas geysers loose their energy. Returning to the place where the Sun is a distant point of light, Comet Ison may never return. Its tail points outward now as the solar wind is at its back, and it fades and the comet falls quiet once more, this time forever.
