This might be the only chance I’ll ever get to post one piece in the two categories of astronomy and coins. Universe Today picked up the story of a 1909 Lincoln Cent being mounted on a calibration target on the Curiosity rover now heading to Mars.
Ken Edgett from the Curiosity team:
The penny is on the MAHLI calibration target as a tip of the hat to geologists’ informal practice of placing a coin or other object of known scale in their photographs. A more formal practice is to use an object with scale marked in millimeters, centimeters or meters.
It’s important for earthbound scientists to be able to compare colors and sizes of objects in images from Martian probes. Hence the color swatches and the markings reminiscent of an eye chart.
Catholic Sensibility 