May 23, 2016[nb 1] is the 23rd day in the month of May 2016.
21:21 EDT: The Watchtower's long-distance sensors pick out the Warworld passing behind Rhea, one of the moons of Saturn. 
21:23 EDT: The Reach detects the Warworld's incursion from their ship in New York City, and the ambassador attempts to dissuade Mongul from his course without success. The Reach's presence on Earth is precisely why Mongul is coming.
↑Series producer Greg Weisman stated that even though the series does not have a "canon year", the production team based the days of the week of season one on the 2010 calendar. In "Happy New Year" there's a five year time jump, making the current year 2016. (Weisman, Greg (2011-11-18). Question #13695. Ask Greg. Retrieved 2011-11-18.).