Small Asteroid Making 400,000 Mile Pass By Earth
AtariKee writes "Universe Today is reporting that a small 10m asteroid, discovered earlier this month and named 2009 BD, is passing within 400,000 miles of Earth. Although the asteroid poses no threat to the planet, the site reports that the asteroid is still very interesting, as it may be a rare co-orbital asteroid (as in, shares the same orbit as Earth)."
Whenever I hear of something like this, I have to wonder if it is a "lost" interplanetary probe (or the upper stage of one, or some other related debris). With this orbit, 2009 BD could be an old lunar flyby, maybe from the 1960's.
Remember, the size estimate requires an albedo estimate, and rocket pieces tend to be very reflective, and thus will appear to be larger if the albedo is set too low, so if it was a spacecraft it would not be 10 meters, but maybe 4 or 5 at most. The Apollo 8, 10 and 11 third stages would be a possible candidate. (After Apollo 11, the third stages were impacted on the Moon to serve as sources for the seismometers.)
Such lost probes will return to near the Earth, but perturbations will tend to move them slowly further away with time.