In 1896, newspapers throughout the United States began reporting accounts of mysterious airships flying overhead. Descriptions varied, but witnesses frequently invoked the century’s great technological achievements.

Some sources reported dirigibles powered by steam engines. Others saw motorized, winged crafts with screw propellers. Many recalled a flying machine equipped with a powerful searchlight.

As technologies of flight evolve, so do the descriptions of unidentified flying objects. The pattern has held in the 21st century as sightings of drone-like objects are reported, drawing concern from military and intelligence officials about possible security threats.

While puzzling over the appearance of curious things overhead may be a constant, how we have done so has changed over time, as the people doing the puzzling change.

In every instance of reporting UFOs, observers have called on their personal experiences and prevailing knowledge of world events to make sense of these nebulous apparitions. In other words, affairs here on earth have consistently colored our perceptions of what is going on over our heads.

Reports of weird, wondrous, and worrying objects in the skies date to ancient times. Well into the 17th century, marvels such as comets and meteors were viewed through the prism of religion—as portents from the gods and, as such, interpreted as holy communications.

By the 19th century, however, “celestial wonders” had lost most of their miraculous aura. Instead, the age of industrialization transferred its awe onto products of human ingenuity.

The steamboat, the locomotive, photography, telegraphy, and the ocean liner were all hailed as “modern wonders” by news outlets and advertisers. All instilled a widespread sense of progress—and opened the door to speculation about whether objects in the sky signaled more changes.