Comet Lovejoy will be closest to Earth on January 7

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Comet Lovejoy, named after Australian astronomer Terry Lovejoy and known by names such as green comet and sun grazer, is flying past the Earth and according to NASA it will be the closest to our planet on January 7 at 70.2 million kilometres.

The comet, previously known as C/2014 Q2, won’t be a bright, brilliant and sky-spanning affair as it cruises past Earth, but on a moonless night you may be able to get a glimpse of it through the unaided eye. If you are in possession of binoculars or a telescope, you will be able to get a much better view.

On December 16 it got closest to the sun at a distance of about 1.29 AU – half the distance between Earth and Mars and it will be returning in the year 2550.

The reason it is also known as the green comet is because of the green colour which is thought to be the result of molecules of diatomic carbon (C2) fluorescing in ultraviolet sunlight in the near-vacuum of space. Cyanogen, CN, can add violet to the green, but because human eyes are fairly insensitive to violet light we only see the green bit.

While viewing with instruments, you might also be able to find a blue tint in the comet’s ion tail and this comes from fluorescing carbon monoxide ions (CO+).

[Editor’s Note: The article has been updated to rectify a typo in the headline and first paragraph]