Dopplervöröseltolódás

Dopplervöröseltolódás, commonly known as the Doppler effect in the context of red or blueshift, describes the change in frequency or wavelength of a wave in relation to an observer who is moving relative to the wave source. When the source of the wave and the observer are moving towards each other, the observed frequency increases, and the wavelength decreases. Conversely, when they are moving away from each other, the observed frequency decreases, and the wavelength increases.

In astronomy, this phenomenon is particularly significant when observing light from celestial objects. If a star or galaxy is moving towards Earth, the light it emits will be shifted towards shorter wavelengths, which in visible light corresponds to a blueshift. If the object is moving away from Earth, its light will be shifted towards longer wavelengths, resulting in a redshift. This is the origin of the term "vöröseltolódás" (redshift) in Hungarian.

The magnitude of the Doppler shift is directly proportional to the relative velocity between the source and the observer. By measuring the Doppler shift in the light from distant galaxies, astronomers can determine their radial velocity – how fast they are moving towards or away from us. This has been a fundamental tool in understanding the expansion of the universe, as most galaxies exhibit a redshift, indicating they are receding from our own. The further away a galaxy is, the greater its redshift, a key observation supporting the Big Bang theory.