Some ancient cultures called them "the threat of the Universe" and "messengers of doom. Comet almost universally perceived by ancient people as messengers of the gods or a bad sign.

Among the ancient people was not distracting tools such as television and the Internet. They turned his gaze to the sky in search of tips and instructions of how to live on Earth and comets, seemed to be signs of divine wrath and inspired the sacred terror.

Although the comet's not uncommon for our solar system, the Great comet appear in the middle of all time in a decade. Size is not the most important distinctive property, Great comets call them simply because they are extremely bright and visible from Earth with the naked eye. As a rule, the reason for this is the small distance between them and the planet.

And now there is a possibility that two Great comet will fly past Earth in 2013.

Astronomers have discovered two new comets, which are fast approaching our planet and perhaps are Great comets. One of them might be "bright enough to be able to see the day", and the second has all chances to become "one of the brightest comets in history," and perhaps even "to overshadow his light to the moon."

The arrival of the first comet, named C/2011 L4 (PANSTARRS), is expected in March 2013. According to astronomers its "potentially can be seen with the naked eye just above the horizon in the Western sky just after sunset"and "it is not excluded that it will be possible to see during the day".

The second comet, which probably will Eclipse the moon, was discovered only in September this year and was named 2012 S1 (ISON). Astronomers predict that "according to the current calculations of the comet's orbit, it will be visible better in a few weeks after its closest approach to the Sun 28 November 2013".

Comet 2012 S1 (ISON) would be visible last two months of next year and in the beginning of 2014, and will be very spectacular astronomical event. The comet is already extraordinary bright, given its distance from the Sun. Moreover, it seems that follows the trajectory of the great comet of 1680 year, which was one of the most famous comet, from all that has ever been seen on Earth.