"Potentially Hazardous" Asteroid to Pass by Earth

Eros, like Apophis, is a near-Earth asteroid. Apophis is a big name in the world of asteroids, and on Wednesday the famed space object will be making an appearance for astronomers across the globe. A flurry of apocalyptic hoopla was generated in 2004 when astronomers found an asteroid that looked like it may be headed for Earth. Apophis measures almost 1000 feet across, and if it were to hit Earth, the fateful collision would occur on Friday the 13th, in April of 2029. So astronomers set out to take more pictures of the asteroid's orbit and better estimate the chances of a collision. As a clearer picture of its orbit emerged, the odds went from 1 in 300, to 1 in 45, to zero. But that doesn't mean the threat is gone. Because Apophis orbits the Earth Apophis's orbit usually places the asteroid between the Earth and the sun, so it is often lost in the glare of the sun and is therefore hard to see with telescopes. But on Wednesday, January 9 the asteroid will cross outside Earth's orbit and offer astronomers a quick and clearer glimpse of the flying chunk of rock. Astronomers are hoping to figure out the asteroid's mass and spin direction, factors which impact its orbit. They also want to know if the gravitational pull from a close call with Earth in 2029 could change the asteroid's orbit and cause a bigger issue when it comes back around a few years later. Astronomers say there is still a small chance of an impact in 2036, so Apophis remains on the International Astronomical Union's list of Potentially Hazardous Asteroids. On Wednesday the asteroid will be 9 million miles above the Earth's surface. Astronomers' best guess for 2029 is far closer than that: a mere 18,000 miles between Apophis and Earth, comparable to the distance to NASA's communication satellites, or one-tenth the distance to the moon. Russia has tentative plans to land a tracking device on the asteroid in order to track it more closely, but for now Wednesday's show will have to satisfy our collective curiosity. Image courtesy of NASA