Final answer:
The factual details included to inform readers in the passage are specifically the location, time, and description of the unidentified object, which are "twenty miles west of Phoenix", "3:15 p.m. on June 12, 2014", and "spherical metal object".
Step-by-step explanation:
The factual details that the author includes to inform readers within the passage are: "twenty miles west of Phoenix", "3:15 p.m. on June 12, 2014", and "spherical metal object". These details provide specific information about the location, time, and physical description of the unidentified object. In contrast, the phrases "Rumors spread" and "concerns about aliens" are not factual details, but rather they describe the public's reaction to the event and their speculations.