Mirage

Since there were no birds to look at, nor photograph, at Barnegat I spent my time looking at ships.

Ships that really weren't there, where "there" was where I was looking.

Got that?

(That "guy" standing on the horizon on the left wasn't really there either.)

The ships were below, or in some cases mostly below, the horizon.

The air acts like a lens bending light rays as they pass through it. Usually, the rays travel in straight lines. But when there is a strong temperature differential the light bends, as it does when passing through a lens.

At the lens-air boundary the air is refracted, which is a fancy word for "bent". You've no doubt noticed how a straw looks bent in a glass of water. The water-air boundary also refracts the light.

The temperature gradient refracts the rays back downwards. Thus rays that would have normally shot well above my head were bent down to my eyes. My, and your, brain expects light to travel in a straight line. Thus we see the ship where a straight light ray would have come from.

A pretty cool trick if you ask me.

🚢  👁  🚢  👁  🚢

You can learn more about mirages on the Atmospheric Optics site, including my Death Valley lake that isn't OPOD.