Asteroid 2017 HG4 flew past Earth at 0.61 LD
A near-Earth asteroid designated 2017 HG4 flew past Earth at a distance of 0.61 LD (~234 240 km / 145 550 miles) on April 22, 2017, four days before it was discovered. This makes it the 20th known asteroid to fly past Earth within 1 lunar distance since January 9,…