Imaging: working out what's inside (with a knife!)

 

Mrs B pointed out that if you slice an apple across the equator, you get a star. I didn't know that. She then pointed out that this is like imaging for medical purposes or for finding out what's inside an atom. What you see depends on which way you slice it - a pole to pole slice of the apple doesn't give a star cavity. Good imaging needs lots of slices in different orientations stitched together.