CLASS 7 · LEARNING KNOWLEDGE

Light as a carrier of information – basic principles

How it works

Light is an electromagnetic wave that transports information about distant objects in space to the Earth. Astronomical observations are based on the fact that light is emitted, reflected, or absorbed by celestial bodies. The color, brightness, and spectrum of light provide clues about properties such as the temperature, composition, and motion of objects. Light propagates at a finite speed, which means we see distant events with a time delay. Different wavelength ranges (e.g. visible light, infrared, ultraviolet) provide different information.

Note
Light transmits information about celestial bodies by bringing their properties such as color, brightness, and spectrum to the Earth; this information makes it possible to draw conclusions about temperature, composition, and motion.

An example

How can the temperature of a star be determined using light?

The color of starlight shows which wavelengths are emitted most strongly. A blue star is hotter than a red one because at higher temperatures more short-wavelength (blue) light is emitted.

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50 Exercises

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Own explanation and own practice exercises by AmyMath. Subject reference framework: Astronomy. The topic assignment may vary by federal state.