The massive space rock, known as 2020 UX3, is estimated to have a diameter between 88 and 196 feet, according to NASA's Center for Near Earth Studies (CNEOS). For comparison purposes, the wingspan of a 747 is 225 feet long. It will come within 3.2 million miles of Earth, traveling at roughly 36,000 miles per hour. Its size and its proximity to Earth make it a near-Earth object (NEO). NASA unveiled a 20-page plan in 2018 that details the steps the U.S. should take to be better prepared for NEOs, such as asteroids and comets that come within 30 million...