It missed Earth by just a few lunar distances.
A three-mile-wide asteroid — dubbed Toutatis — missed Earth on Tuesday, the latest passing for the gigantic cosmic beast. When the asteroid flew past Earth, it was traveling at approximately 39,600 kilometers per hour (24,550 miles per hour), according to NASA, which observed the passing from a number of various locations throughout the U.S.
A number of amateur astronomers around the world had the chance to observe the somewhat rare event. This year the asteroid came within 4.3 million miles of our planet — or about 18 lunar distances — at its closest point early Wednesday. The asteroid, which is officially known as Asteroid 4179, was captured by the online Slooh Space Camera and Virtual Telescope Project, among a number of observatories hosting viewing parties across the globe.
“Slooh technical staff let the public follow this fast-moving asteroid in two different ways. In one view, the background stars was tracked at their own rate and the asteroid appeared as an obvious streak or a moving time-lapse dot across the starry field,” said Astronomy Magazine columnist Bob Berman in a statement describing the viewing event. “In a second view, Toutatis itself was tracked and held steady as a tiny pointlike object, while Earth’s spin made the background stars whiz by as streaks. Both methods made the asteroid’s speedy orbital motion obvious as it passed us in space.”
The event allowed both NASA and a number of international observatories to study its spin and its orbit, which is slightly adjusted each time it passes Earth. According to NASA, Toutatis has one of the strangest rotation states observed in the solar system. Instead of spinning around a single axis, as do the planets and the vast majority of asteroids, it tumbles somewhat like a football after a botched pass. Unlike planets and the vast majority of asteroids, which rotate around a single pole, Toutatis has two spin axes. It twirls around one with a period of 5.4 Earth-days and the other once every 7.3 days.
“Toutatis has a 3:1 orbital resonance with Jupiter and a 1:4 resonance with Earth,” explained one NASA official familiar with the asteroid. “Thus, every third time Toutatis orbits the Sun, it returns to the same spot relative to Jupiter. Every 4th time Earth goes around the Sun, it and Toutatis end up in the same relative position as well. Up until about 1922, Toutatis also had numerous close-approaches to Venus and Mars.”
While the asteroid’s size is considered large by astronomical standards — the asteroid that is thought to have killed the dinosaurs was six miles wide — it does not poise any threat to Earth, according to NASA. Due to the asteroid’s orbit, it is not likely to impact Earth anytime within the next 600 years.
Asteroid Toutatis was first viewed in 1934, then officially discovered in 1989. It makes one trip around the sun every four years. It is expected to pass by Earth again in 2016.