There are five primary types (bottom row) of pigment-filled sacks, called melanosomes, within the nanostructure (left)` of iridescent feathers. Thick rods are found in birds with weak iridescent ...

Now let’s say you’re on the Moon. If you were to drop a hammer and a feather from the same height, which would hit the ground first? Click the graphic below to find out. Spaceman: Well ...