Asteroid 2010 AL30, discovered by the LINEAR survey of MIT’s Lincoln Laboratories on Jan. 10, will make a close approach to the Earth’s surface to within 76,000 miles on Wednesday January 13 at 12:46 pm Greenwich time (7:46 EST, 4:46 PST). Because its orbital period is nearly identical to the Earth’s one year period, some have suggested it may be a manmade rocket stage in orbit about the Sun. However, this object’s orbit, reaches the orbit of Venus at its closest point to the Sun and nearly out to the orbit of Mars at its furthest point, crossing the Earth’s orbit at a very steep angle, and this actually makes it very unlikely that 2010 AL30 is a rocket stage. Furthermore, our trajectory extrapolations show that this object cannot be associated with any recent launch and it has not made any close approaches to the Earth since well before the Space Age began.
It seems more likely that this is a near-Earth asteroid about 10-15 meters across, one of approximately 2 million such objects in near-Earth space. One would expect a near-Earth asteroid of this size to pass within the moon’s distance about once every week on average.
To take advantage of this close approach, there are plans to observe it with the Goldstone planetary radar on Wednesday evening, Jan. 13 beginning at 6:20 PST. The radar data could dramatically improve the object’s orbit and provide additional information on its size and shape.