The value of a redshift is denoted by the letter z, corresponding to the fractional change in wavelength, positive for redshifts, negative for blueshifts, and by the wavelength ratio 1 + z, which is >1 for redshifts, <1 for blueshifts. And so, red-shift (z,>1) is the displacement of spectral lines towards longer wavelengths (Δλ+λ)>λ i.e. the red end of the electromagnetic spectrum.
The wavelength λ of a wave is directly proportional to the time period T of the wave (λ ∝ T), and energy of the wave (E) is directly proportional to the frequency of the wave (E ∝ f).
The time interval for 1° of phase is inversely proportional to the frequency (f). If the frequency of a signal is given by f, then the time t (deg), in seconds, corresponding to 1° of phase is t (deg) = 1/(360f) = t/360. Therefore, a 1° phase shift on a 5 MHz signal corresponds to a time shift of 555 picoseconds (ps).
Accordingly, the corresponding increments in degree (°) phase shifts on a given signal frequency, there is increment in time shifts (Δt).
Therefore, the redshifts occur through the phase shift in wave frequency due to infinitesimal loss in wave energy (ΔE) and corresponding enlargement in the wavelength (Δλ) of the wave.
Various Redshifts
The
electromagnetic radiation, like light, from distant galaxies and celestial
objects, interpreted as a Doppler shift that is proportional to the velocity of
recession and thus to distance of the galaxy.
Moreover, the universe is expanding, and that expansion stretches the wavelength of light traveling through space in a phenomenon known as cosmological redshift.
Furthermore, there is gravitational redshift, also known as Einstein shift; it is the phenomenon that electromagnetic waves or photons traveling out of a gravitational well lose energy, this corresponds to longer wavelengths (λ)
Ther three known types of redshifts are, Doppler redshift, Gravitational redshift and Cosmological redshift.1. Doppler redshift, a phenomenon observed in the context of the Doppler effect. The Doppler effect describes the change in the frequency or wavelength of a wave as a result of the relative motion between the wave source and the observer.
Z denotes the redshift factor which represents the fractional change in wavelength;
- Z = {λ(obs)-λ(rest)}/λ(rest); where,
λ(obs) represents the observed wavelength of light;
λ(rest) represents the rest wavelength of light;
In the context of light, Doppler redshift refers to the observed increase in wavelength (or decrease in frequency) of light from a source moving away from the observer. The formula given above calculates the redshift factor, denoted "Z", which represents the fractional change in wavelength.
In the formula, λ(obs) represents the observed wavelength of light, while λ(rest) represents the remaining wavelength of light, which is the wavelength that would be measured if the source were stationary relative to the observer.By comparing the observed wavelength with the rest wavelength, the Doppler redshift can be determined, which indicates the relative motion between the source and the observer. A positive value of Z indicates that the source is moving away, causing the observed wavelength to become longer (red-shifted), whereas a negative value of Z indicates motion toward the observer (blue-shifted).Doppler redshift has important applications in many fields of science, including astronomy, where it is used to study the motion and expansion of celestial objects such as galaxies and large-scale structures in the universe. It provides valuable information about the velocity and distance of these objects based on observed changes in their spectral lines.2. Gravitational redshift, denoted Z, is a phenomenon predicted by the theory of general relativity. This refers to the change in wavelength (or equivalently, frequency) of light as it travels through a gravitational field, such as near a massive object.
- Z = Δλ/λ₀; where,
Z denotes the redshift factor which represents the fractional change in wavelength;Δλ is the change in wavelength of light as observed;λ₀ is the wavelength at the source.
As light travels through a gravitational field, it loses energy in the light, causing it to shift to longer wavelengths (or lower frequencies). The formula given above calculates the redshift factor, denoted "Z", which represents the fractional change in wavelength.The magnitude of the gravitational redshift depends on the strength of the gravitational field experienced by the light and the proximity of the massive object. The closer the light source is to a massive object, or the stronger the gravitational field it crosses, the greater the redshift observed.Gravitational redshift has been observed and measured in a variety of contexts, such as in experiments conducted on Earth and through astronomical observations. This provided evidence for the gravitational nature of light and confirmed predictions of gravitational fields.3. Cosmic redshift (Z) is a phenomenon observed in astronomy in which light emitted from distant celestial objects such as galaxies or quasars is shifted to longer wavelengths (lower frequencies) as it travels through expanding distance. This is the result of the expansion of distance among the objects in the universe.
- Z = Δλ/λ₀; where,
Z denotes the redshift factor which represents the fractional change in wavelength;Δλ is the change in wavelength of light as observed;λ₀ is the wavelength at the source.
According to the conventional cosmological model, the Big Bang theory, the universe is constantly expanding. As space expands, it carries light waves with it, causing them to expand and resulting in a red shift. The formula given above calculates the redshift factor, denoted "Z", which represents the fractional change in wavelength.The magnitude of the cosmic redshift is directly related to the distance between the observer and the light source. The farther away an object is, the more space it has traveled during its journey and the greater the observed cosmic redshift.Cosmic redshifts have been observed and measured in countless astronomical observations, providing strong evidence for the expansion of the distance within the universe. The redshift of distant galaxies was first observed by Edwin Hubble in the 1920s, leading to the discovery of the expanding distance within the universe and the formulation of Hubble's law, which describes the relationship between the redshift of galaxies and their distance from us.Cosmological redshift is an essential tool in studying the large-scale structure and evolution of the universe. It allows astronomers to estimate the distances to remote objects, determine the expansion rate of the universe (Hubble constant), and investigate the nature of dark energy, which is believed to be driving the accelerated expansion of the distance within the universe.
Spectroscopy (Additional)
The
spectroscopy is used as a tool for studying the structures of atoms and
molecules. The large number of wavelengths emitted by these systems makes it
possible to investigate their structures in detail, including the electron
configurations of ground and various excited states. From spectral lines
astronomers can determine not only the element, but the temperature and density
of that element in the star. The spectral line also can tell us about any
magnetic field of the star. The width of the line can tell us how fast the
material is moving.
#Redshift #gravitationalredshift #spatialexpansionalredshift #dopplerredshift #wave #WaveEnergy #LossOfWaveEnergy
