'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
ebooks
ebooksA special investigation by Andy McSmith
Life and Style
Powdered colors are displayed for sale at a market ahead of the Holi festival in Bhopal, India
techHere's what you need to know about the riotous occasion
Arts and Entertainment
Larry David and Rosie Perez in ‘Fish in the Dark’
theatreReview: Had Fish in the Dark been penned by a civilian it would have barely got a reading, let alone £10m advance sales
News
Details of the self-cleaning coating were published last night in the journal Science
science
News
Approved Food sell products past their sell-by dates at discounted prices
i100
News
Life-changing: Simone de Beauvoir in 1947, two years before she wrote 'The Second Sex', credited as the starting point of second wave feminism
peopleHer seminal feminist polemic, The Second Sex, has been published in short-form to mark International Women's Day
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: Finance Assistant / Credit Controller

£16000 - £18000 per annum: Recruitment Genius: They are an award-winning digit...

Ashdown Group: Senior VMware Platform Engineer - VMware / SAN / Tier3 DC

£45000 - £55000 per annum + benefits: Ashdown Group: Senior VMware Platform En...

Recruitment Genius: Purchasing Assistant

£10000 - £16000 per annum: Recruitment Genius: A distributor of specialist ele...

Recruitment Genius: Sales Ledger Assistant

£17000 - £19000 per annum: Recruitment Genius: A distributor of specialist ele...

Day In a Page

Homeless Veterans campaign: Donations hit record-breaking £1m target after £300,000 gift from Lloyds Bank

Homeless Veterans campaign

Donations hit record-breaking £1m target after huge gift from Lloyds Bank
Flight MH370 a year on: Lost without a trace – but the search goes on

Lost without a trace

But, a year on, the search continues for Flight MH370
Germany's spymasters left red-faced after thieves break into brand new secret service HQ and steal taps

Germany's spy HQ springs a leak

Thieves break into new €1.5bn complex... to steal taps
International Women's Day 2015: Celebrating the whirlwind wit of Simone de Beauvoir

Whirlwind wit of Simone de Beauvoir

Simone de Beauvoir's seminal feminist polemic, 'The Second Sex', has been published in short-form for International Women's Day
Mark Zuckerberg’s hiring policy might suit him – but it wouldn’t work for me

Mark Zuckerberg’s hiring policy might suit him – but it wouldn’t work for me

Why would I want to employ someone I’d be happy to have as my boss, asks Simon Kelner
Confessions of a planespotter: With three Britons under arrest in the UAE, the perils have never been more apparent

Confessions of a planespotter

With three Britons under arrest in the UAE, the perils have never been more apparent. Sam Masters explains the appeal
Russia's gulag museum 'makes no mention' of Stalin's atrocities

Russia's gulag museum

Ministry of Culture-run site 'makes no mention' of Stalin's atrocities
The big fresh food con: Alarming truth behind the chocolate muffin that won't decay

The big fresh food con

Joanna Blythman reveals the alarming truth behind the chocolate muffin that won't decay
Virginia Ironside was my landlady: What is it like to live with an agony aunt on call 24/7?

Virginia Ironside was my landlady

Tim Willis reveals what it's like to live with an agony aunt on call 24/7
Paris Fashion Week 2015: The wit and wisdom of Manish Arora's exercise in high camp

Paris Fashion Week 2015

The wit and wisdom of Manish Arora's exercise in high camp
8 best workout DVDs

8 best workout DVDs

If your 'New Year new you' regime hasn’t lasted beyond February, why not try working out from home?
Paul Scholes column: I don't believe Jonny Evans was spitting at Papiss Cissé. It was a reflex. But what the Newcastle striker did next was horrible

Paul Scholes column

I don't believe Evans was spitting at Cissé. It was a reflex. But what the Newcastle striker did next was horrible
Miguel Layun interview: From the Azteca to Vicarage Road with a million followers

From the Azteca to Vicarage Road with a million followers

Miguel Layun is a star in Mexico where he was criticised for leaving to join Watford. But he says he sees the bigger picture
Frank Warren column: Amir Khan ready to meet winner of Floyd Mayweather v Manny Pacquiao

Khan ready to meet winner of Mayweather v Pacquiao

The Bolton fighter is unlikely to take on Kell Brook with two superstar opponents on the horizon, says Frank Warren
War with Isis: Iraq's government fights to win back Tikrit from militants - but then what?

Baghdad fights to win back Tikrit from Isis – but then what?

Patrick Cockburn reports from Kirkuk on a conflict which sectarianism has made intractable