Popular Science

To have a notion of temperature, you need to have a notion of interaction

A gamma ray burst is a focused stream of energy that can last from just a few seconds to several minutes. Just one 10-second burst releases more energy than our Sun will produce over its 10-billion-year lifetime

the name for the change in sound as waves from the source move closer or farther away from you, elongating as they move away and shortening as they come closer. Visible light, as seen in the colors of the rainbow, exhibits similar properties, with longer wavelengths appearing as a red shift and shorter wavelengths as a blue shift.