Michael Kelley, a scientist working on the Nasa TC4 observation campaign, said: "Scientists have always appreciated knowing when an asteroid will make a close approach to and safely pass the Earth because they can make preparations to collect data to characterise and learn as much as possible about it". It passed our planet at a distance only a quarter of that between the Earth and the Moon.
He said: "We've now been observing TC4 for two months, so we have very accurate position information on it, which in turn allows very precise calculations of its orbit, which will not cross that of Earth nor its satellites". On October 12, 2017, this asteroid will make another close flyby of Earth.
It is roughly the same size as the meteor that caused widespread damage when it exploded in the atmosphere over Chelyabinsk in central Russian Federation in 2013.
The resulting shockwave blew out the windows of almost 5,000 buildings and injured more than 1,200 people. It was traced way back in 2012 and its one of those thousands of space rocks whose whereabouts are known.
TC4 is one of about three similar-sized objects that pass the Earth at the equivalent projected distance every year.
Observatories around the world have been working to track the asteroid over the past several weeks, using it as an exercise to test the early warning network that would be used should another future space rock pose a real threat of impact.
"For us this is a test case", said Detlef Koschny of the European Space Agency's Near-Earth Object programme. The very amusing Joanne McNally and Bernard Casey joined us on the sofa, Kymann and Dara put an age-old food rivalry to the test, Shifts had a really awkward chat with their barber, the super-talented Tara Lee played a cracking Magic Cover and one girl even travelled all the way from Cavan for a free burger.
Studies of this asteroid's light curve found that it has a rotation period of just under 12¼ minutes with a brightness variation of nearly a magnitude, which indicates that 2012 TC4 has a non-spherical (most likely elongated) shape.
Its closest point of contact with earth will be over Antarctica at around 6:40am, GMT.
Nor will you not be able to see it with the naked eye.