The strongest consensus (nearunanimous of the astronomical community is that the redshifts of distant galaxies indicate that all distant galaxies arerecedingfrom us. This recession is currently the only known mechanism for redshifting light. Take this inference, that all galaxies arereceding and you are led to the idea that the universe is expanding, a phenomena described by Hubble's Law. This is a central tenet to the Big Bang Theory.
I will include the counterpoint originally described below, but I will point out that the papers cited are very old, and a huge number of corroborating observations and predictions of the big bang haveoccurredsince then.
The conclusion that the Universe is expanding is a wrong conclusion. Alan Sandage talks about Hubble's position at the related link below.
To the very end of his writings he maintained this position, favouring (or at the very least keeping open) the model where no true expansion exists, and therefore that the redshift "represents a hitherto unrecognized principle of nature". This viewpoint is emphasized (a) in The Realm of the Nebulae, (b) in his reply (Hubble 1937a) to the criticisms of the 1936 papers by Eddington and by McVittie, and (c) in his 1937 Rhodes Lectures published as The Observational Approach to Cosmology (Hubble 1937b). It also persists in his last published scientific paper which is an account of his Darwin Lecture (Hubble 1953).
The best diagram to represent the pattern of spectral lines from the same element observed by Edwin Hubble in the light of distant galaxies is the redshift spectrum. This spectrum shows the spectral lines of elements shifted toward longer wavelengths (redshifted) due to the Doppler effect, indicating that the galaxies are moving away from us. The pattern of these lines remains consistent with the element's known absorption or emission spectrum, but the entire set of lines shifts uniformly to the red, reflecting the expansion of the universe.
Because the sun is rotating. So its west limb is moving away from us and its east limb is moving toward us ... the exact conditions required in order to shift the emission spectrum.
If a star is moving towards Earth. The light is seen as 'blue shifted'. As we look at our sun, on the colour spectrum, black lines appear. When looking at distant stars, we can tell if they are moving away from us (Red shift) or getting closer to us (Blue shift). This is because the black lines shift to the red or blue end of the spectrum depending on which direction the star is travelling.
The spectral lines of Barnard's Star are shifted toward the blue end of the spectrum due to the Doppler effect, indicating that the star is moving towards us. This blue shift occurs because the wavelengths of the light emitted by the star are compressed as it approaches, resulting in higher frequency and shorter wavelength light. This motion can be attributed to the star's proper motion relative to Earth. Such shifts are crucial for astronomers to understand stellar dynamics and distances.
When galaxies experience blue shift, they are moving closer to us. This phenomenon occurs when the light emitted by the galaxy is compressed into shorter wavelengths, shifting it toward the blue end of the spectrum. Blue shift is typically observed in galaxies that are part of a gravitational interaction or are falling into a larger galaxy. In contrast, galaxies moving away from us experience red shift, where the light is stretched into longer wavelengths.
Galaxies are moving away from each other in a constantly expanding universe
There isn't a particular name, however, when they are moving towards us, their spectrum is shifted to the blue region. So they are referred to as blue shifted galaxies but that is only relative to ourselves. See related link for more information.
The observed redshift in the spectra of galaxies indicates that they are moving away from us, which supports the theory of an expanding universe. As galaxies recede, the light they emit stretches to longer wavelengths, shifting toward the red end of the spectrum. This phenomenon is a key piece of evidence for the Big Bang theory, suggesting that the universe has been expanding since its inception. Additionally, the degree of redshift can help astronomers determine the distance and velocity of distant galaxies.
No. You can figure out exactly what elements are in stars and galaxies by examining the color spectrum of the light detected; the frequencies of the bright and dark lines in the spectrum tell you what's what. But there's a problem. For distant galaxies, the light spectrum is wrong. The frequency lines of the spectrum are all too low. One possible explanation of the incorrect spectrum is that those stars and galaxies are MOVING AWAY from us, and that the spectrum is shifted toward the red end of the color spectrum because of the Doppler effect. So scientists believe that the "red-shift" on the color spectrum of stars and galaxies indicate that they are moving away. Not all galaxies show a red-shift; the Andromeda Galaxy, M31, shows a pronounced BLUE-shift, indicating that it is heading TOWARD us. In fact, scientists believe that the Milky Way and Andromeda will probably collide in about 3 billion years.
He noted that light emitted from stars is shifted further toward the red of the electromagnetic spectrum . From this he concluded that the universe was expanding.
In simplest terms, the shift of galactic spectral lines towards the red end of the spectrum would indicate simply that the galaxy in question is receding from the observer. This is an example of the Doppler effect, where the frequency is lowered (wavelengths become longer, and in this case energy of the photons is decreased) by the relative motion of the observer. The redshifting of galaxies in all directions became the primary evidence of an expanding universe (cosmological redshift). Because the expansion of the universe is fairly uniform in all directions, those galaxies that are most distant are receding the fastest and thus evidence the greatest amount of redshift. By contrast, if a characteristic spectral line of a galaxy or other object shifted towards the blue end of the spectrum (shorter wavelengths), it would be traveling towards the observer.
The best diagram to represent the pattern of spectral lines from the same element observed by Edwin Hubble in the light of distant galaxies is the redshift spectrum. This spectrum shows the spectral lines of elements shifted toward longer wavelengths (redshifted) due to the Doppler effect, indicating that the galaxies are moving away from us. The pattern of these lines remains consistent with the element's known absorption or emission spectrum, but the entire set of lines shifts uniformly to the red, reflecting the expansion of the universe.
If light is subject to the Doppler effect, it will change color. The light changes color toward the lower (red) end of the spectrum or the upper (blue) end of the spectrum. Which way the color shifts depends on whether the distance between the source and the observer is increasing or decreasing. Should we find the distance is increasing, the light will be shifted toward the red end of the spectrum. This is called redshift (one word), and astronomers know this well because most all galaxies are speeding away from the Milky Way and have their light shifted toward the red end of the spectrum. If the distance between a source and observer is decreasing, the color of the light will be shifted toward the blue end of the spectrum. In either case, the amount the color is shifted will be determined by the rate the distance between the source and observer is changing. If a galaxy is moving away from the Milky Way, we'll see a shift toward red, and if another galaxy is moving away faster, will see a greater shift in the color of the light from it.
nice question! actually when a wave approaches an observer the wave length of the wave decrease and as it move far from us its wavelength increase. it is quiet difficult to understand so use your imagination. as the wavelenght increase the spectrum will be shifted toward red spectrum and thus called red shift. when Edward Hubble studies spectrum of different star he noticed that because of some color spectrum were missing, other spectrum got shifted to ward red. it it moved toward red then that mean that wavelength was increasing and if wavelength increases then that means light moves away from us and thus he concluded that each and every star and galaxy was moving away from each other
If a star is moving toward Earth, it will experience a redshift in its light spectrum due to the Doppler effect. This means that the wavelengths of light will be stretched and appear more red. This effect allows astronomers to measure the speed and direction of a star's movement.
Because the sun is rotating. So its west limb is moving away from us and its east limb is moving toward us ... the exact conditions required in order to shift the emission spectrum.
If a star is moving towards Earth. The light is seen as 'blue shifted'. As we look at our sun, on the colour spectrum, black lines appear. When looking at distant stars, we can tell if they are moving away from us (Red shift) or getting closer to us (Blue shift). This is because the black lines shift to the red or blue end of the spectrum depending on which direction the star is travelling.