The "redshift" refers to the fact that the light is less energetic than when it was emitted; it shows that the galaxies move away from us. Should a galaxy move towards us - which is possible only for galaxies that are relatively close to us - then there would be a blueshift.
The blue shift phenomenon was discovered by the American astronomer Edwin Hubble in the 1920s. He observed that the light from distant galaxies appeared shifted towards the blue end of the spectrum, indicating that these galaxies were moving away from us. This discovery provided crucial evidence for the expansion of the universe.
Moving away from us
I would think that current evidence suggests that the stars moving away from earth, some of them in far distant galaxies moving at unimaginably high speeds, are going much faster than stars moving toward us. The entire Andromeda galaxy is moving toward us and will collide with us in roughly 5 billion years, and it is not moving anywhere near as fast as the distant retreating galaxies.
The light from distant galaxies shows redshift because the universe is expanding. As the galaxies move away from us, the light they emit gets stretched, causing its wavelength to increase and shift towards the red end of the spectrum. This redshift can help scientists determine the velocity at which galaxies are moving away from us and provide insights into the expansion of the universe.
The spectra of distant galaxies collected today support Hubble's original findings by showing that galaxies are moving away from us, indicating an expanding universe. The redshift in the spectra is evidence of this cosmic expansion, consistent with Hubble's discovery of the relationship between distance and redshift.
Galaxies in the expanding universe are moving away from each other at speeds proportional to their distance, with more distant galaxies moving faster. This phenomenon is known as the expansion of the universe.
No.More specifically:Not all galaxies are moving away from each other. The Milky Way and Andromeda galaxies are moving towards each other (and at a pretty good clip, too: about 300 km/s). The entire "local group" of galaxies is moving in the general direction of something called the "Shapley Supercluster".Very distant galaxies do tend to be moving away from each other, but that means the universe is expanding, not contracting.
No, redshift refers to the phenomenon where the light from celestial objects appears to be shifting towards longer wavelengths, indicating that the object is moving away from the observer, including Earth. This is a key piece of evidence for the expansion of the universe and is commonly observed as a feature of distant galaxies.
Distant galaxies are moving away from Earth at faster speeds compared to nearby galaxies. This is due to the expansion of the universe, where galaxies farther away experience a greater redshift, indicating faster recession velocities. This relationship is described by Hubble's Law, which states that the recessional velocity of a galaxy is directly proportional to its distance from us.
The light from distant galaxies is redshifted. The only reasonable explanation for that is that the galaxies are moving away from us.
We know the universe is expanding because we can measure the redshift of distant galaxies. This redshift indicates that galaxies are moving away from us, and the further away a galaxy is, the faster it is moving away. This observation supports the idea of an expanding universe.
Hubble discovered that the redshift of distant galaxies indicated that the universe is expanding, which provided evidence for the Big Bang theory. This observation also led to the realization that galaxies are moving away from each other, with those farther away moving faster, suggesting an overall expansion of the universe.