398E-439-Big and Close

Using our Schmidt telescope on Mt. Bigelow, Arizona, my Catalina Sky Survey teammate Richard Kowalski was searching for Earth approaching asteroids in the constellation of Virgo when he discovered a moving point of light which had suddenly appeared and was about 40 times brighter than is typical for a near Earth asteroid. 75 hours later, scientists at the Minor Planet Center used data from 17 different observatories around the globe to calculate it's orbit around the Sun, estimate it's size to be 630 feet in diameter, and give it the name 2018 BT6. Three weeks before Richard discovered 2018 BT6, it was very dim with less than 1% of it's illuminated side facing us as it came from the direction of the Sun giving humans little advance notice as it approached us at a speedy 16.4 mi/s. In 2018 this relatively large space rock came to about 18 times the Moon's distance from us. In the future it's orbit can bring it to about 0.6 of the Moon's distance from us. According to the Purdue University and Imperial College of London's impact calculator, one it's size impacts the Earth every 300,000 years or so creating a crater in sedimentary rock 7 miles in diameter and 2,000 feet deep. Fortunately 2018 BT6 will not strike the Earth in the foreseeable future, however, it's discovery presents us with the fact that currently humans would have little advance warning of the impact of a relatively large space rock if it approached us from the direction of our Sun.