JOIN USAstronomers have aimed their telescopes to catch a glimpse of the 2005 YU55 asteroid, which will not be visible to the naked eye, when it makes its closest approach to earth at 6:28 pm (2328 GMT).
The 1,300-foot-wide asteroid often travels in the vicinity of the earth, Mars and Venus, but “the 2011 encounter with earth is the closest it has come for at least the last 200 years,” the US space agency said.
Other asteroids of this size pass by earth more frequently, though the last such event happened in 1976 and the next will not happen again until 2028 when as asteroid called 2001 WN5 will skim about halfway between the moon and earth.
This asteroid is expected to pass a bit further away; about .85 times the distance of the moon to the earth, or a distance of 3,25,000 kilometres.
“2005 YU55 is one of the potentially hazardous asteroids that make close approaches from time to time because their orbits either approach or intersect the orbit of the earth,” said Robert McMillan, an associate research scientist at the University of Arizona.
McMillan discovered the asteroid in 2005 as part of the university’s Spacewatch Project, a solar-system-scanning group of scientists near Tucson, Arizona.
However, astronomers know from analysing the trajectory of the asteroid that it will not hit earth this time.
The asteroid’s next closest pass is set to take place in 2094, at a distance of 2,69,000 kilometres, according to forecasts.