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A 'red shift' is the increase in the wavelength of light received from astronomical
objects, compared to what we know the wavelength should be. It's called "red
shift" because if the wavelength of some visible light is increased, the color of the
light changes in the direction of the color with the longest visible wavelength, which
is red. If the shift is really substantial, light that left a star at visible wavelengths
may even red-shift completely out of the visible range, and arrive here as infrared
radiation.
The only mechanism we know of that can increase the wavelength of light ...
without the light passing into a different medium ... is the receding (moving away)
of the light source from us, and it's generally agreed that if the light we receive from
an astronomical object is red-shifted, then the object is moving away from us. The
faster the object is moving away from us, the greater the increase in the wavelength
of its light.
This is a big deal in Astronomy and Cosmology. If it's true, then there have been
enough observations of red shift over the past hundred years to reveal the general
pattern that ALL of the distant objects in the universe are moving away from us, and
the farther from us they already are, the faster they're moving away. This is the basis
of the statement you've heard that "the Universe is expanding".
Notes:
1) If thelight source ismoving toward us, then its light arrives here blue-shifted ... with
shorter wavelengths than we know it had when it left the source. There's not much of
that to be seen, and it's all coming from objects that are relatively close to us.
2) Strictly speaking, the expanding Universe causes the "Cosmological Redshift"
which is similar to, but different from, the "Doppler Effect".
3) There is, in fact, another mechanism for producing a redshift. Strong gravitational fields can have this effect. Some astronomers used to argue
this was a possible explanation for the redshifts of some galaxies.
However the consensus now is that it's the expansion of space that's by far the most likely cause of the redshifts of galaxies.
Red shift is the phenomenon in which light from distant galaxies appears to be shifted towards longer (redder) wavelengths as they move away from us. This effect is a key piece of evidence for the expansion of the universe, as it indicates that galaxies are moving away from each other and suggests an overall increase in the universe's size over time.
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What is red-shift and what does the size of the redshift tell us about the distant galaxies?
Red shift is the apparent elongation of the wavelength of light reaching us from distant sources of light due to the expansion of space in between. The amount of red shift can be used to work out the recessional velocity of a galaxy and it's distance from us.
What does the red shift tell scientists?
The redshift tells scientists how fast a star or galaxy is moving away from us.
What does red shift tell us about other galaxies?
Red shift indicates that other galaxies are moving away from us, implying that the universe is expanding. This phenomenon is a key piece of evidence supporting the Big Bang theory. The amount of red shift is used to determine the distance and speed at which other galaxies are moving relative to us.
What does a red shift tell astronomers about stars or galaxies?
A red shift in the light emitted by a star or galaxy indicates that it is moving away from us. By measuring the amount of red shift, astronomers can determine the speed at which the object is receding and use this information to study the expansion of the universe and the distance to the object.
Would a light source moving away from Earth appear blue shifted or red shifted?
A red shift indicates an object that is moving away from the observer, and a blue shift indicates an object that is moving toward the observer. Both of these are called Doppler shifts.
What is red-shift and what does the size of the redshift tell us about the distant galaxies?
Red shift is the apparent elongation of the wavelength of light reaching us from distant sources of light due to the expansion of space in between. The amount of red shift can be used to work out the recessional velocity of a galaxy and it's distance from us.
What does the red shift tell scientists?
The redshift tells scientists how fast a star or galaxy is moving away from us.
What does red shift tell us about other galaxies?
Red shift indicates that other galaxies are moving away from us, implying that the universe is expanding. This phenomenon is a key piece of evidence supporting the Big Bang theory. The amount of red shift is used to determine the distance and speed at which other galaxies are moving relative to us.
What does a red shift tell astronomers about stars or galaxies?
A red shift in the light emitted by a star or galaxy indicates that it is moving away from us. By measuring the amount of red shift, astronomers can determine the speed at which the object is receding and use this information to study the expansion of the universe and the distance to the object.
Would a light source moving away from Earth appear blue shifted or red shifted?
A red shift indicates an object that is moving away from the observer, and a blue shift indicates an object that is moving toward the observer. Both of these are called Doppler shifts.
What does a red shift tell astronomers about the movement of an object?
A red shift indicates that an object is moving away from the observer. This is a result of the Doppler effect, where light waves are stretched as an object moves away, causing them to shift towards the red end of the spectrum. Astronomers can use red shifts to determine the speed and direction of an object's movement.
How does blue and red shift help us understand the changes of the universe?
Red shift has confirmed the expansion of universe. Both red and blue shift at the edges of the sun has confirmed the spin of sun..
What is the red shift of hydrogen?
The red shift depends on the relative motion of the emitting source and receiving detector. Hydrogen per se has no red shift. There is hydrogen with great red shift (in stars in galaxies far away that are moving rapidly away from us).
What does the red shift of the galaxies tell us about their motion with respect to the Earth?
The red shift of galaxies indicates that they are moving away from the Earth. This is a key piece of evidence for the expansion of the universe. The greater the red shift, the faster the galaxy is moving away from us.
What is red shift inti?
When galaxies move away from us, the waves of light stretch out- ie, they become redder. The greater the red shift, the faster the galaxies are moving away from us.
Why are red shift and blue shift effects useful in the study of the universe?
Red shift means that other objects in the universe are moving away and blue shift means they are moving toward you. This helps to tell where these objects came from, and this knowledge helps predict where they are going to.
How can an object's red shift tell us how fast the object is moving away from earth?
The amount of reddening is directly proportional to the speed of the object away from the observer (if the object is moving tangentially, even at a high speed, no red shift will be noticeable. Follow the link below for a bit more information on the mathematics and measurements of red shifts.
