The asteroid, known as 216258 2006 WH1, is set for its closest approach to Earth on December 20 - just days before Christmas. The 540 metre space rock is the same size as the World Trade Centre and would cause a significant amount of damage and mass extinction.

The asteroid is currently thought to be hurtling towards the Earth at a speed of 43,200km/h or 26,843mph.

The asteroids course could be further influenced by natural a phenomenon known as the Yarkovksey effect.

The effect occurs when the gentle force of sunlight edges an asteroid either way of its natural course.

Its influence on an asteroid was demonstrated in 2012 with mastoid 1999RQ36.

Scientists, using the Yarkovksey effect, were able to estimate the most accurate determination of an asteroids orbit to date.

Asteroids larger than approximately 35 metres across pose a threat to a town or city, this meaning that 216258 2006 WH1s 540 metre diameter would likely cause havoc across the globe.

The asteroid hasnt yet been measured on the Torio Impact Hazard Scale, but will likely be listed as a serious threat when and if it is added.

A stripped down version of the Torino Scale was presented to the United Nations in 1995.

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Then, a revised version was presented in 1999 at a conference on Near Earth Objects (NEO).

It was at this conference that participants voted to make the revised version the main scale that scientists would use and refer to when labelling the threat asteroids posed to Earth.

The system has an integer scale ranging from 0 to 10 with associated colour coding.

It currently captures the likelihood and consequences of a potential impact event.

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A ten on the scale means a collision is certain, capable of causing global climatic catastrophe that may threaten the future of civilisation as we know it, whether colliding with land or ocean.

Such events occur on average once per 100,000 years, or less often.

A one on the scale corresponds to a routine and "normal" discovery.

This "normal" terminology only came about in 2005, when a one on the scale initially meant events meriting careful monitoring.

This resulted in exaggerated press coverage as scale one asteroids were relatively common, so the terminology had to be changed to normal so as to avoid stirring mass panic and attention.

For these asteroids, the calculations show the chance of collision is extremely unlikely with no cause for public attention or concern.

New telescopic observations very likely will lead to re-assignment of those originally classed as level one to eventually become a Level zero.

Organisations like NASA and the European Space Agency (ESA) keep a watchful eye on NEOs passing close to Earth.

NEOs are all comets and asteroids whose orbits approach Earths path around the Sun.

NASA said: An NEO includes any asteroid, meteoroid or comet orbiting the Sun within 18,600,000 miles, 30 million km, of Earth's orbit.

Out of the 829,361 known asteroids and 3,592 known comets in the system, more than 20,000 space rocks are ranked as NEOs.

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Asteroid terror: NASA spot mammoth space rock to hit Earth's orbit five days before X-mas - Express.co.uk