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When hearing to a sound from a moving source, we notice a change in pitch (frequency) as that source moves towards us, and then passes us and moves away, eg. think of the difference in sound frequency of fast moving cars if you've ever seen a formula 1 grand prix. This difference in pitch is due to the Doppler effect.
The Doppler effect can also be observed in light waves. To understand this, we first need to explore what is meant by a spectrum and how it is observed.
When white light passes through a prism, it is dispersed, in other words, split into its component colours (red, orange, yellow, green, blue, indigo, violet - the colours of the rainbow). This is known as the visible spectrum of light. The colours of the spectrum always appear in this order, and its important to remember that the colour of light depends on its frequency. Blue light has a high frequency, and red light a low frequency. Now, when we observe the spectrum of light from a hot glowing gas (such as hydrogen or helium as in a star), we won't see all the colours, but only certain lines (this is due to the change in energy levels of electrons within the H or He atoms). The resulting spectrum is known as a line emission spectrum. Since all stars are made of the same gases, when we look at their line emission spectra, the lines of colour should all be the same compared compared to each other.
However, we notice that the line spectra of distant stars are shifted closer to the red end of the spectrum, (the colours will be "redder") meaning that the light reaching us is at a lowerfrequency than we expect. This means that the source of the light, the star, "must" be moving, just as in the Doppler effect applied to sound, a car moving away from us would have a lower pitch.
If the moving object was approaching us, we would see light as a higher frequency, and therefore the lines in the emission spectra would shift toward the blue end of the spectrum.
The key to understanding the red shift is to remember the Doppler effect in terms of the moving car, and to remember that colour is the frequency ("pitch") of a light wave.
First: sound Doppler is not quite Relativistic Doppler.
Second: a shift towards the red end of the spectrum means the light has lost energy. Could be lost to movement, a Doppler shift, or could be lost due to gravity, a gravity-hole effect.
What else can I help you with?
Does the velocity of a star toward or away from earth determine measuring the shift of its spectral lines?
Yes. If the star is moving away from the Earth, its spectral lines will shift towards the red end of the spectrum. If it is moving towards the Earth, its spectral lines will shift towards the violet end of the spectrum. This is due to Doppler effect.
What does a blue shift in the spectrum indicate?
A blue shift in the spectrum indicates that an object is moving toward the observer, resulting in a decrease in the wavelength of the emitted light. This phenomenon is often observed in astronomy, where it can signify that a star or galaxy is approaching Earth. The shift towards the blue end of the spectrum occurs due to the Doppler effect, which affects the frequency of waves as the source moves relative to an observer.
How do you know if a star is moving toward us or away?
This is determined by measuring the "red shift" or "blue shift" of the star, or in other words, whether its perceived color on earth is shifted towards the red end of the spectrum or towards the blue end. This color shift effect is similar to the Doppler effect in that it is caused by the compression or rarefaction of waves by a moving object. So a star moving away from us would look slightly more red than usual because the light waves that reach us are drawn out due to the motion of the star. And conversely, a star moving towards us would look slightly more blue than usual, for the same reason.
What is the difference between the red shift and the blue shift?
A "redshift" is a change in the light observed from a source to longer wavelengths. That's a change from the blue end of the spectrum to the red end of the spectrum. A "blueshift" is the opposite. It's a change towards shorter wavelengths.
A red shift in the spectrum of the light from an object indicates the object is moving where?
A red shift in the spectrum of light from an object indicates that the object is moving away from the observer. This is a result of the Doppler effect, where the wavelengths of light are stretched as the object moves away, causing a shift towards the red end of the spectrum.
What does a shift toward the blue end of the spectrum mean?
A shift toward the blue end of the spectrum means that the light being observed has a higher frequency and shorter wavelength compared to light at the red end of the spectrum. This shift is known as "blue shift" and is commonly seen in scenarios where the light source is moving closer to the observer, such as with objects moving towards Earth in the universe.
Does the velocity of a star toward or away from earth determine measuring the shift of its spectral lines?
Yes. If the star is moving away from the Earth, its spectral lines will shift towards the red end of the spectrum. If it is moving towards the Earth, its spectral lines will shift towards the violet end of the spectrum. This is due to Doppler effect.
What does the blue shift mean in regard to stars and galaxies?
Light is a spectrum. On one end it is red and the other blue. We see light in this spectrum as waves and if it is blue, the object is coming toward us. If the waves are red than it is moving away. The frequency of these waves tell us how fast and object is moving toward or away from us.
When the wavelength of a spectral line emitted from an object increases which end of the visible light spectrum does not move toward and what is the objects motion relative to earth?
Increasing wavelength is an indication of a Doppler shift caused by an object moving away from the viewer. Longer wavelengths (of the visible spectrum) are redder, shorter wavelengths are bluer. Objects moving away from you have a red shift, objects moving toward you have a blue shift.
When the absorption line of a galaxy shift toward the blue end of the spectrum it means that the galaxy is?
It means the heading towards us, red means it is moving away from us.
What does it mean if a star is experiencing a red shift?
redshift is what happens when visible light gets longer in wavelength, thus shifting toward the red end of the spectrum of visible light. This is a phenomenon that occurs when the light source is moving away from the observer.
If light experiences the Doppler effect what will happen to its color?
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.
What is a Blue shift star?
A blue shift star is a star that appears bluer than normal due to its motion toward Earth, causing a shift of its spectral lines towards the blue end of the spectrum. This phenomenon is known as the Doppler effect and is used in astronomy to study the movement of celestial objects.
How do you know if a star is moving toward us or away?
This is determined by measuring the "red shift" or "blue shift" of the star, or in other words, whether its perceived color on earth is shifted towards the red end of the spectrum or towards the blue end. This color shift effect is similar to the Doppler effect in that it is caused by the compression or rarefaction of waves by a moving object. So a star moving away from us would look slightly more red than usual because the light waves that reach us are drawn out due to the motion of the star. And conversely, a star moving towards us would look slightly more blue than usual, for the same reason.
What causes a blue shift?
A blue shift occurs when an object is moving towards an observer, causing the light waves to compress and shift towards the higher energy blue end of the spectrum. This can happen due to the Doppler effect, gravitational effects, or cosmological expansion.
When the wavelength of the spectral line emitted from an object decreases which end of the visible light spectrum does it move toward and what is the object's motion relative to Earth?
If the wavelength decreases, the spectral line moves towards the blue end of the visible light spectrum. This phenomenon is known as blue shift, indicating that the object is moving towards Earth.
What happen to the spectrum of a star moving toward the earth away from the earth?
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.
