A newly discovered asteroid designated 2017 YZ4 will flyby Earth at a distance of 0.00150 AU or 0.58 LD (~224 396 km / 139 433 miles) on December 28, 2017. This is the first known asteroid to flyby Earth within 1 lunar distance since November 21 and the 52nd this year.
YZ4 was first observed at Mt. Lemmon Survey on December 25th. It belongs to the Apollo group of asteroids and has an estimated diameter of 6.9 to 15 m (22.6 to 49 feet).
It will flyby Earth at a speed (relative to the Earth) of 9.55 km/s at 15:56 UTC on December 28.
This is the first known asteroid to flyby Earth within 1 lunar distance since 2 such asteroids flew past us 35 minutes apart on November 21. It is also the 52nd of the year and the sixth since November 1, after very active October with 11 known <1 LD flybys.
As of December 24, there are 17 495 known Near-Earth Objects (NEOs) around our planet; 17 389 are asteroids.
This year, we discovered 1 985 NEOs. 1888 such objects were discovered in 2016 and 1 571 in 2015.
Featured image: The green line indicates the object's apparent motion relative to the Earth, and the bright green marks are the object's location at approximately one-hour intervals. The Moon's orbit is grey. The blue arrow points in the direction of Earth's motion and the yellow arrow points toward the Sun. Credit: Minor Planet Center.