Browsing NASA’s gallery of Astronaut photography of Earth today, I came across this gem of an image of the Scilly Isles.

Notice the diffraction of the waves around the small islands in the bottom left? Here’s a closer look:

The Isles of Scilly, seen from Space, showing wave diffraction pattern around islands

Detail of the Isles of Scilly, seen from Space. (NASA Photo ID ISS014-E-16597)

Whilst it’s not exactly news to anyone that waves diffract, I thought it was incredibly cool to see such an impressive example of the phenomenon in nature.

Doing some more digging, it seems that the crew of Apollo 7 took a similar image (frame AS7-4-1607 of Magazine N) during their mission. Sadly, it doesn’t seem like any of the frames from that magazine have been digitised. The only other references are in a scientific paper (§ 2.5 Space Photography) where the image is completely unintelligible and in a picture book digitised by the Internet Archive which doesn’t seem to be at a high enough resolution to see the pattern.

In any case, one diffraction pattern is exciting enough!

Earth Science and Remote Sensing Unit, NASA Johnson Space Centre
Earth Science and Remote Sensing Unit, NASA Johnson Space Centre