The hunk of rock, dubbed 4179 Toutatis, made its closest approach during the early hours of Wednesday morning, getting within 6.9 million kilometres of our planet, or approximately 18 times the distance between the Earth and the moon.
Anyone with a moderate to large backyard telescope will be able to see the asteroid over the next few days, as it passes through the constellations of Cetus and Pisces.
Several websites are tracking the asteroid as it flies by. The Slooh Space Camera project is providing a live view of the asteroid on its website, streaming from observatories in Arizona and the Canary Islands, off the coast of Africa.
The Bellatrix Astronomical Observatory, located in Ceccano, Italy, is also offering a live stream as part of the Virtual Telescope Project.
The lumpy, elongated rock has an unstable orbit, circling the sun in a looping oval that ranges from just inside Earth's orbit to well beyond Mars.
First sighted in 1934, Toutatis has frequently been making close approaches to Earth, nearing the planet's vicinity every four years since its formal discovery in 1989. It came particularly close in 2004 — about four times the distance between the Earth and the moon.
Because of its orbit and its frequent near-approaches, Toutatis is classified as a potentially hazardous asteroid.
“This [most recent approach] has gotten tied up in some people’s minds with the Mayan calendar and the world ending,” Alan MacRobert, senior editor at Sky and Telescope Magazine, told the Boston Globe.
“It’s not going to end the world.”
Astronomers predict that eventually, Toutatis will be flung either into the Sun or completely out of the solar system by Jupiter's orbit.
There is also the possibility that it may some day collide with the Earth — but astronomers say that likely won't happen for at least another 600 years.
NASA's Near-Earth Object program office tracks the paths of both near-Earth asteroids and comets. As of Dec. 9, 2012, the NEO office said it has discovered 9,487 near-Earth asteroids.Suggest a correction