Similarity Across Scales at the Extreme: Shapes of Pleurosigma and the Milky Way

January 14, 2020

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Image of Milky Way: From Optical Gravitational Lensing Experiment (OGLE) survey and the University of Warsaw
Photo of Pleurosigma: John Stetson 
Summary Author: John Stetson 

Shown above, at top, is a photo of a sample of micro-life collected from a plankton tow at Casco Bay in Maine. This Pleurosigma is about 155 microns in length and has a distinct disk-like shape. It’s been rotated here (note that Pleurosigma actually do rotate as they swim through water) to match the orientation of our galaxy, the Milky Way (bottom photo). This image of the Milky Way was composed from the Optical Gravitational Lensing Experiment (OGLE) survey and the Astronomical Observatory at the University of Warsaw.

The similarities across scales between the micro-life and Milky Way is quite interesting. Sir Isaac Newton said the following on the subject of similarity across scales: "Nature is very similar to itself...performing all the great movements of celestial bodies with the help of attraction, gravity...and every small particle motion of these bodies...with the help of other attractive and repulsive forces binding particles.” See the Earth Science Picture of the Day for April 5, 2017 – a comparison between a gravitational lens and a medusa.