ABOUT X-RAYS: Like visible light, X-rays are wavelike forms of electromagnetic energy carried by tiny particles called photons. The higher energy level of the individual photons and the corresponding shorter wavelengths of X-rays makes them undetectable by the human eye. X-ray photons have energies that range from hundreds to thousands of times higher than those of visible photons. X-ray machines image the outline of bones and organs, while a CT scan machine forms a full three-dimensional computer model of the inside of a patient's body. Doctors can even examine the body one narrow slice at a time. The X-ray beam moves all around the patient, scanning from hundreds of different angles, and the computer takes all that information to compile a 3D image of the body.
WHAT IS SPECTROSCOPY? Spectroscopy is a technique used by astronomers and physicists to study the make-up of an object based on the light it emits. Anything that produces light or radiates energy, whether a light bulb or a star, is telling us about itself and anything between us and the source. This is possible because each chemical element has a unique signature, emitting or absorbing radiation at specific wavelengths. For example, sodium, used in street lights, emits primarily orange light. Oxygen, used in neon lights, emits green light. By passing the light from a star or other object through a special instrument, called a spectrograph, the light is "spread" into a spectrum in much the same way visible light is spread into its colors by a prism. By carefully studying how the spectrum becomes brighter or darker at each wavelength, scientists can tell what chemical elements are present.
The American Physical Society and the Optical Society of America contributed to the information contained in the TV portion of this report. This report has also been produced thanks to a generous grant from the Camille and Henry Dreyfus Foundation, Inc.