Friday seems to be a triple-header for cosmic events: A penumbral lunar eclipse will coincide with Harvest full moon and a 200-foot-wide (60 meter) asteroid will streak past Earth.
The asteroid, which could be 20 to 61 meters long, has been monitored by the Mt. Lemmon Survey, in the Mount Lemmon Observatory, in the Santa Catalina Mountains, near Tucson, Arizona, which discovered it on August 28, 2016.
The space rock, which is estimated to be up to 61 metres in length, is predicted to whistle past our planet at 31,000 miles per hour, on September 17, but NASA is not even certain of the time of the pass due to relying on estimated calculations, and could be up to 16 minutes out on the estimated flyby.
Although 2016 QL44 is expected to pass by us at 3.6 times the distance from us to the Moon (857,000 miles) on September 17, 2016 any asteroid that comes within 10 million miles of Earth is considered a “near Earth asteroid” due to the relative closeness that is in terms of the solar system.
So those which are just a few lunar distances are considered extremely close passes.
On top of this, NASA has given the space rock a condition code of nine – which is the least certain it can be about its orbital route out of any asteroid.
The asteroid called 2016 QL44 has been monitored by NASA and other agencies ever since because of the uncertain orbit. http://neo.jpl.nasa.gov/ca/