Spectra are often punctuated with emission or absorption lines, which can be examined to reveal the composition and motion of the radiating source. A temporary disturbed area in the solar photosphere that appears dark because it is cooler than the surrounding areas. Sunspots consist of concentrations of strong magnetic flux. They usually occur in pairs or groups of opposite polarity that move in unison across the face of the Sun as it rotates. A three-dimensional plot mapping the intensity of radiation from a region as a distorted surface.
More intense radiation is represented by higher points on the surface.
Therefore, regions of intense radiation resemble mountains on the earth. Thermal Gas A collection of particles that collide with each other and exchange energy frequently, giving a distribution of particle energies that can be characterized by a single temperature. Thermal Particle A particle that is part of a thermal gas . Thermal Radiation Electromagnetic radiation emitted by electrons in a thermal gas . The combination of atomic nuclei at high temperatures to form more massive nuclei with the simultaneous release of energy.