The year 2013 could be marked by sightings of two bright comets, one of which could be the brightest comet sighting in history.

Astronomers, however, are careful not to spark too much anticipation because comets can be unpredictable, reports Space.com.

"Comets are like cats; they have tails, and they do precisely what they want," Space.com quoted comet specialist David Levy.

Photo of the comet Hale-Bopp above a tree. This picture was taken in the vicinity of Pazin in Istria/Croatia during a short easter holiday. The tree was illuminated using a small flashlight. To the lower right of the comet the Andromeda Galaxy M31 is also faintly visible. (Photo by Philipp Salzgeber for Wiki Commons.)

2013 Year of the Comets: Comet C/2011 L4, Comet C/2012 S1

Here are 5 things to know about two comets that could grace the Earth sky in 2013.

1. Two comets are likely to make a show this year. They are called Comet C/2011 L4 and Comet C/2012 S1.

2. Comet C/2011 L4, discovered in 2011, was confirmed by Richard Wainscoat, a member of the Pan-STARRS (Panoramic Survey Telescope and Rapid Response System) team.

3. Comet C/2011 L4 will be at its brightest on March 10, but observers from the Southern Hemisphere could see it with their naked eye by early February. By March 10th this comet will pass close to the sun and become visible to Northern Hemisphere observers. Sunset watchers could spot it "just above and to the left of the setting sun," says the Space.com report. It will maintain its brightness until early April.

4. Comet C/2012 S1 was discovered just last year by two amateur astronomers through a telescope in Russia. Vitali Nevski of Belarus and Artyom Novichonok of Russia discovered the comet through the International Scientific Optical Network (ISON).

5. Comet C/2012 S1 is a "sun grazer," which means it makes a close approach to the sun. At such a small distance, it can potentially be even brighter than the full moon. It could be possible to see it at daytime. The bright sight could last until January 2014. Early morning sky observers from both hemispheres could spot it by early November. It will be very close to the sun on Nov. 28.

When a comet gets close to the sun, its ice component is vaporized by solar wind, thus creating its tail. a comet's tail always extends away from the sun because of the solar wind blow.

Suffice it to say that "2013 year of the comets" possibility is real, albeit astronomers have witnessed some disappointments in the past, as pointed out by Levy.

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