The basic idea behind interferometry is that light travels in waves, and the light waves from one object (or one part of an object) can “interfere,” or interact, with the light waves from another object (or another part of that same object). Imagine dropping two pebbles a small distance apart into a pond. The waves made by each pebble interfere with one another, causing wavy ripples of different sizes and shapes. In much the same way, when light waves interfere, they produce similar patterns of light, dark, and color. By measuring and studying those interference patterns, astronomers can reconstruct images and deduce other information about the light sources that produced the patterns in the first place, often with much greater detail than would be possible by simply taking an image straight-on.