This stunning picture shows comet Lulin glowing green in the sky as it makes its closest approach to Earth










Green light for a close encounter: 'Jupiter-sized' comet to streak past Earth tonight
24th February 2009

We have known of its existence for only two years. But if you raise your eyes heavenwards tonight, you might just catch a glimpse of the comet Lulin.

Glowing green, it will come within 38million miles of Earth, the closest it has ever been, and about the same distance away as Mars.

Lulin, photographed here by an astronomer in Arizona, was discovered by a 19-year-old student from a photo taken at Lulin Observatory-Taiwan, in 2007.











                          


Comet Lulin is delighting amateur astronomers who are observing it using telescopes and binoculars

The spectacular comet will be visible to the naked eye over the next few nights.

Its colour comes from the gases that make up its Jupiter-sized atmosphere.

The stellar traveller is very active, shedding nearly 800 gallons of water each second on its journey around the Sun. That's enough liquid to fill an Olympic-sized swimming pool in less than 15 minutes.

Jets from the nucleus throw out cyanogen, a poisonous gas found in many comets, and diatomic carbon, which glow green when lit by sunlight.

It could be visible any time after dark.

Nasa said: 'Dark country skies will be required. But no one can say for sure. This appears to be Lulin's first visit to the inner solar system and its first exposure to intense sunlight. Surprises are possible.'

Andrew Read, from Leicester University, said: 'The comet is releasing a great amount of gas, which makes it an ideal target for X-ray observations.'

                        

Astronomers using the Nasa Swift Satellite are tracking a spectacular comet as it closes in on Earth and sheds gas and dust from its vaporised ice. This combined view shows combined ultraviolet and X-ray images of the object

To see Comet Lulin with your own eyes, set your alarm for 1am when the comet will be highest in the sky. It will be visible due south near Saturn, moving towards the west as dawn approaches.

British astronomers from Leicester University will study the comet using the NASA Swift Satellite to find out more about its chemistry and gather clues about the origin of comets and the solar system.