'Brighter than a full moon': The biggest star of 2013... could be Ison - the comet of the century

view gallery VIEW GALLERY

A comet discovered by two Russian astronomers will be visible from Earth next year. Get ready for a  once-in-a lifetime light show, says David Whitehouse

At the moment it is a faint object, visible only in sophisticated telescopes as a point of light moving slowly against the background stars. It doesn't seem much – a frozen chunk of rock and ice – one of many moving in the depths of space. But this one is being tracked with eager anticipation by astronomers from around the world, and in a year everyone could know its name.

Comet Ison could draw millions out into the dark to witness what could be the brightest comet seen in many generations – brighter even than the full Moon.

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. Astronomers Vitali Nevski and Artyom Novichonok were expecting to use the International Scientific Optical Network's (Ison) 40cm telescope on the night of 20 September but clouds halted their plans.

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. A database search showed it has been seen in images taken by other telescopes earlier that year and in late 2011. 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 – a quarter of the way to the nearest star. 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. Its life has been cold, frozen hard and unchanging, but it is moving closer to the Sun, and getting warmer.

Ison's surface is very dark – darker than asphalt – pockmarked and dusty 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.

By the end of summer it will become visible in small telescopes and binoculars. By October it will pass close to Mars and things will begin to stir. The surface will shift as the ice responds to the thermal shock, cracks will appear in the crust, tiny puffs of gas will rise from it as it is warmed. The comet's tail is forming.

Slowly at first but with increasing vigour, as it passes the orbit of Earth, the gas and dust geysers will gather force. The space around the comet becomes brilliant as the ice below the surface turns into gas and erupts, reflecting the light of the Sun. Now Ison is surrounded by a cloud of gas called the coma, hundreds of thousands of miles from side to side. The comet's rotation curves these jets into space as they trail into spirals behind it. As they move out the gas trails are stopped and blown backwards by the Solar Wind.

By late November it will be visible to the unaided eye just after dark in the same direction as the setting Sun. Its tail could stretch like a searchlight into the sky above the horizon. Then it will swing rapidly around the Sun, passing within two million miles of it, far closer than any planet ever does, to emerge visible in the evening sky heading northward towards the pole star. It could be an "unaided eye" object for months. When it is close in its approach to the Sun it could become intensely brilliant but at that stage it would be difficult and dangerous to see without special instrumentation as it would be only a degree from the sun.

Remarkably Ison might not be the only spectacular comet visible next year. Another comet, called 2014 L4 (PanSTARRS), was discovered last year and in March and April it could also be a magnificent object in the evening sky. 2013 could be the year of the great comets.

As Comet Ison heads back to deep space in 2014 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.

Dr David Whitehouse is an author and astronomer

Start your day with The Independent, sign up for daily news emails
News
newsAnother week, another dress controversy on the internet
Life and Style
Scientist have developed a test which predicts whether you'll live for another ten years
health
Life and Style
Marie had fake ID, in the name of Johanna Koch, after she evaded capture by the Nazis in wartime Berlin
historyOne woman's secret life as a Jew in wartime Berlin
News
news... and what your reaction to the creatures above says about you
ebooks
ebooksA special investigation by Andy McSmith
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Recruitment Genius: Telesales & Customer Service Executive - Call Centre Jobs

£7 - £9 per hour: Recruitment Genius: Are you outgoing? Do you want to work in...

Ashdown Group: Finance Manager - Covent Garden, central London - £45k - £55k

£45000 - £55000 per annum + 30 days holiday: Ashdown Group: Finance Manager - ...

Ashdown Group: Systems Administrator - Lancashire - £30,000

£28000 - £30000 per annum: Ashdown Group: 3rd Line Support Engineer / Network ...

Recruitment Genius: Graduate Web Developer

£26000 - £33000 per annum: Recruitment Genius: A Web Developer is required to ...

Day In a Page

Syrian conflict is the world's first 'climate change war', say scientists, but it won't be the last one

Climate change key in Syrian conflict

And it will trigger more war in future
How I outwitted the Gestapo

How I outwitted the Gestapo

My life as a Jew in wartime Berlin
The nation's favourite animal revealed

The nation's favourite animal revealed

Women like cuddly creatures whilst men like creepy-crawlies
Is this the way to get young people to vote?

Getting young people to vote

From #VOTESELFISH to Bite the Ballot
Poldark star Heida Reed: 'I don't think a single bodice gets ripped'

Poldark star Heida Reed

'I don't think a single bodice gets ripped'
The difference between America and Israel? There isn’t one

The difference between America and Israel? There isn’t one

Netanyahu knows he can get away with anything in America, says Robert Fisk
Families clubbing together to build their own affordable accommodation

Do It Yourself approach to securing a new house

Community land trusts marking a new trend for taking the initiative away from developers
Head of WWF UK: We didn’t send Cameron to the Arctic to see green ideas freeze

David Nussbaum: We didn’t send Cameron to the Arctic to see green ideas freeze

The head of WWF UK remains sanguine despite the Government’s failure to live up to its pledges on the environment
Author Kazuo Ishiguro on being inspired by shoot-outs and samurai

Author Kazuo Ishiguro on being inspired by shoot-outs and samurai

Set in a mythologised 5th-century Britain, ‘The Buried Giant’ is a strange beast
With money, corruption and drugs, this monk fears Buddhism in Thailand is a ‘poisoned fruit’

Money, corruption and drugs

The monk who fears Buddhism in Thailand is a ‘poisoned fruit’
America's first slavery museum established at Django Unchained plantation - 150 years after slavery outlawed

150 years after it was outlawed...

... America's first slavery museum is established in Louisiana
Kelly Clarkson: How I snubbed Simon Cowell and become a Grammy-winning superstar

Kelly Clarkson: How I snubbed Simon Cowell and become a Grammy-winning superstar

The first 'American Idol' winner on how she manages to remain her own woman – Jane Austen fascination and all
Tony Oursler on exploring our uneasy relationship with technology with his new show

You won't believe your eyes

Tony Oursler's new show explores our uneasy relationship with technology. He's one of a growing number of artists with that preoccupation
Ian Herbert: Peter Moores must go. He should never have been brought back to fail again

Moores must go. He should never have been brought back to fail again

The England coach leaves players to find solutions - which makes you wonder where he adds value, says Ian Herbert
War with Isis: Fears that the looming battle for Mosul will unleash 'a million refugees'

The battle for Mosul will unleash 'a million refugees'

Aid agencies prepare for vast exodus following planned Iraqi offensive against the Isis-held city, reports Patrick Cockburn