According to NASA's calculations, the space rock will likely never get anywhere near impacting Earth ... according to EarthSky. You can find out where it will be in the sky by using TheSkyLive.com.
But Mars, Jupiter, Saturn and Venus should be visible to the naked eye. For this alignment, Mercury will be on the far side of the sun, according to EarthSky. And being so close to the sun, it will be ...
according to EarthSky. Asteroid 2011 UL21 is 1.4 miles wild, according to Space Reference, making it larger than 99% of all known near-Earth objects and roughly comparable to Mount Everest.