Photo: AP
The comet is being tracked by NASA's Swift Gamma-ray Explorer satellite which captured this image of it travelling through the constellation Libra.
While all the planets and most of the other objects in the solar system circle the sun anticlockwise, Lulin circles clockwise.
And thanks to an optical illusion, from Earth it appears as if the comet's tail is in the front as it approaches.
Lulin was only discovered in 2007 ago by Ye Quanzhi and Lin Chi-Sheng from the Lulin Observatory in Taiwan.
It will come closest to Earth – about 38 million miles, or 160 times farther than the moon – on February 24.
For most locations in the Northern Hemisphere, Lulin will be easiest to spot after midnight, when it is high in the sky.
Joe Rao, SPACE.com's Night Sky Columnist, said: "For those not-so-seasoned folks, I would advise them not to expect anything awe-inspiring,.
"Visually to the naked eye in a dark sky, Lulin looks like a dim, fuzzy 'star' and in a small telescope it appears like a fuzzball ... somewhat brighter and more concentrated near the centre and more diffuse around the edges. As comets go, it's nice, but casual skywatchers are more likely to say, 'That's it?' as opposed to more experienced observers who might actually utter, 'Oh, wow'."
The comet has a green hue because of the chemicals in its head, or coma, however, viewing it could be challenging for novice astronomers.
NASA has also discovered that Lulin is shedding enough water to fill an Olympic-size swimming pool every 15 minutes, as the sun boils its surface material away.
Lulin will finally fade from our view by mid-March.
Comet Lulin in January and February 2009. 
For the next few days, a newly discovered, green-tinted comet will be visible by the naked eye in most parts of the Northern Hemisphere. Comet Lulin, with the official designation of C/2007 N3, was discovered in 2007 and astronomers say that this is the first time it has visited our solar system and may well be the last.

As it makes its way around the Sun, an astonishing 800 gallons (3 m3) of water will evaporate from the comet every second. In each 15 minute period, it will shed enough water to fill an Olympic sized swimming pool. It will come within 38 million miles of Earth at its closest pass, making it visible to the naked eye and even clearer with binoculars or a telescope. 

The best viewing time for people living in the northern hemisphere is after midnight when Lulin will be at its highest point in the sky, or 40 degrees from the morning horizon. Current estimates peg the maximum brightness at 4th or 5th magnitude, which means dark country skies would be required to see it. No one can say for sure, however, because this is Lulin's first visit.

Astronomers from NASA and the United Kingdom will use the Swift Telescope to study the comet and its composition. Astronomers also say to see it while you can because this could be the first and only time it passes through our solar system. It's estimated that if it returns, it will not be for another 1,000,000 years.

"We won't be able to send a space probe to the comet, but Swift is giving us some of the information we would get from just such a mission," said Jenny Carter, at the University of Leicester in England, who is leading the study.

The comet was discovered using the Lulin Observatory in Taiwan by astronomers Ye Quanzhi and Lin Chi-Sheng.