Flutterby™! :

ONE-MILE-WIDE ASTEROID TO PASS CLOSER THAN THE MOON IN 2028 Excerpts from the URL at http://cfa-www.harvard.edu/iau/pressreleases/1997XF11.html tell us: Recent orbit computations on an asteroid discovered last December indicate it virtually certain that it will pass within the moon's distance of the earth a little more than 30 years from now. The chance of an actual collision is small, but one is not entirely out of the question. The asteroid, known as 1997 XF11, was discovered by Jim Scotti in the course of the Spacewatch program at the University of Arizona. This program utilizes modern electronic technology on a 36-inch telescope at Kitt Peak that was built 77 years ago. [snip] Observations made on March 3 and 4 by Peter Shelus with a 30-inch telescope at the McDonald Observatory in western Texas extended the observed arc of 1997 XF11 to 88 days. This time, the orbit computation indicated a miss distance of only 30 thousand miles from the center of the earth; the earth's radius is about 4 thousand miles. The time of encounter would be around 1:30 p.m. Eastern Daylight Time on Thursday, October 26, 2028. That evening the object should be visible with the naked eye. In Europe, where it would be dark by that time, the object should be a splendid sight as it moves from northwest to southeast across the sky over a couple of hours.