Starship Asterisk*

A Full Plankton Moon

Explanation: What glows in the night? This night featured a combination of usual and unusual glows. Perhaps the most usual glow was from the Moon, a potentially familiar object. The full Moon's nearly vertical descent results from the observer being near Earth's equator. As the Moon sets, air and aerosols in [url=https://climate.nasa.gov/news/2919/eart ... ered-cake/" >Earth's atmosphere</a> preferentially scatter out blue light, making the <a href="ap220515.html]Sun-reflecting satellite[/url] appear reddish when near the horizon. Perhaps the most unusual glow was from the bioluminescent plankton, likely less familiar objects. These [url=https://en.wikipedia.org/wiki/Plankton# ... ankton.jpg" >microscopic creatures</a> glow blue, it is thought, primarily to <a href="https://assets-global.website-files.com ... %20Dog.jpg]surprise[/url] and deter predators. In this case, the glow was caused primarily by plankton-containing waves crashing onto the beach. The image was taken on Soneva Fushi Island, Maldives just over one year ago.

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Fantastic colors!


That's a gorgeous "Moon reddening sequence", as the Moon is seen to sink - vertically! - towards the horizon through thicker and thicker layers of atmosphere (and likely clouds). It is, in a way, a picture-perfect illustration of why stars get reddened when there is interstellar dust between us and them.

Of course, the color of the plankton is just jaw-dropping. Particularly when you consider the contrast between the ochre-colored sand, the strikingly cyan-green ocean and the "neon blue" plankton.

I have been swimming in bioluminescent plankton myself, off the coast of Gothenburg at 57^o north, but it wasn't as neon blue as the it is in the APOD. It was more blue-white. The video below shows bioluminescent plankton off the coast of Strömstad, at latitude 56.58^o north:


Ann