The atmospheric motion toward us, away from the solar surface, is seen as a blue shift, and is the beginning of the solar wind. The blue regions are inside a coronal hole, or open magnetic field region, where the high speed solar wind is accelerated. For 30 years, scientists have observed high speed solar wind coming from regions in the solar atmosphere with open magnetic field lines, called coronal holes. The identification of the detailed structure of the source region of the fast solar wind is an important step in solving the solar wind acceleration problem. A spectrum results from the separation of light into its component colors, which correspond to different wavelengths.
Blue light has a shorter wavelength and is more energetic than red light.
A spectrum is similar to what is seen when a prism separates white light into a rainbow of distinct colors. By analyzing light this way, astronomers learn a great deal about the object emitting the light, such as its temperature, chemical composition, and motion. The solar wind is a high speed stream of electrically charged gas flowing from the surface of the Sun. The hot gas in the solar wind source region emits light at certain ultraviolet wavelengths. When the hot gas flows towards Earth, as it does in the solar wind, the wavelengths of the ultraviolet light emitted become shorter, a phenomenon called Doppler effect.