#PPOD: Here is another cool rock at Gale crater on Mars! The spikes are most likely the cemented fillings of ancient fractures in a sedimentary rock. The rest of the rock was made of softer material and was eroded away. 📷: @NASA@NASAJPL@Caltech#MSSS fredk, acquired on May 17.
#PPOD: This spectacular image is a composite of two images. Jupiter and its Great Red Spot were captured by @NASAVoyager 1 on 4 March 1979, while the image of volcanic moon Io was taken by NASA's Galileo on 4 April 1997. Credit: @NASA@NASAJPL Björn Jönsson @uarizona