When light shifts toward the blue end of the spectrum, it is shifting in the direction of shorter wavelengths. This happens when a luminous object, such as a star, is moving toward you. This motion tends to compress the waves which it emits. Stars that are moving away from the observer will instead exhibit a red shift. The waves are stretching out, because of the motion. And because the universe is expanding, red shifts are by far the most common.
When light shifts toward the blue end of the spectrum, it is shifting in the direction of shorter wavelengths. This happens when a luminous object, such as a star, is moving toward you. This motion tends to compress the waves which it emits. Stars that are moving away from the observer will instead exhibit a red shift. The waves are stretching out, because of the motion. And because the universe is expanding, red shifts are by far the most common.
The frequency of light from a star is reduced (its wavelength increased) when the star is moving away from the observer. Red light has longer wavelengths than blue light. So the light from a star which is moving away from the earth appears to be redder than it actually was. This phenomenon is similar to the pitch of an ambulance siren dropping as it passes you and is moving away. The true spectrum for light from a star depends on the temperature of the star, but there are characteristic absorption lines (dark lines) in the spectrum which are specific to chemical elements which are present in the outer regions of the stars - such as hydrogen and helium. Light from within the star is absorbed by the atoms of these elements when they move from a low-energy state to one with a higher energy level. A comparison of where in the spectrum these lines appear to be against where they should be (for a stationary) star are a measure of the red-shift (or blue shift).A red shift is observed if an object is moving away from the earth while a blue shift is observed if it is approaching the earth.
In that case, the star must be approaching us.
All stars are hot. Blue stars are the hottest. The hotter a star is, the shorter the wavelength of light it emits. Blue light has a shorter wavelengths than most other colors.
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.
They can do so by examining the light from the star. Doppler shift can indicate this
it Will not be a star
When light shifts toward the blue end of the spectrum, it is shifting in the direction of shorter wavelengths. This happens when a luminous object, such as a star, is moving toward you. This motion tends to compress the waves which it emits. Stars that are moving away from the observer will instead exhibit a red shift. The waves are stretching out, because of the motion. And because the universe is expanding, red shifts are by far the most common.
The frequency of light from a star is reduced (its wavelength increased) when the star is moving away from the observer. Red light has longer wavelengths than blue light. So the light from a star which is moving away from the earth appears to be redder than it actually was. This phenomenon is similar to the pitch of an ambulance siren dropping as it passes you and is moving away. The true spectrum for light from a star depends on the temperature of the star, but there are characteristic absorption lines (dark lines) in the spectrum which are specific to chemical elements which are present in the outer regions of the stars - such as hydrogen and helium. Light from within the star is absorbed by the atoms of these elements when they move from a low-energy state to one with a higher energy level. A comparison of where in the spectrum these lines appear to be against where they should be (for a stationary) star are a measure of the red-shift (or blue shift).A red shift is observed if an object is moving away from the earth while a blue shift is observed if it is approaching the earth.
The frequency of light from a star is reduced (its wavelength increased) when the star is moving away from the observer. Red light has longer wavelengths than blue light. So the light from a star which is moving away from the earth appears to be redder than it actually was. This phenomenon is similar to the pitch of an ambulance siren dropping as it passes you and is moving away. The true spectrum for light from a star depends on the temperature of the star, but there are characteristic absorption lines (dark lines) in the spectrum which are specific to chemical elements which are present in the outer regions of the stars - such as hydrogen and helium. Light from within the star is absorbed by the atoms of these elements when they move from a low-energy state to one with a higher energy level. A comparison of where in the spectrum these lines appear to be against where they should be (for a stationary) star are a measure of the red-shift (or blue shift).A red shift is observed if an object is moving away from the earth while a blue shift is observed if it is approaching the earth.
Not at all. "Blue shift" refers to a shift of features in the star's spectrum toward shorter wavelengths, for stars that are moving toward us. It has nothing at all to do with the composition or properties of the star itself.
Yes
In that case, the star must be approaching us.
light is put into a spectrum from red to blue. red shift is when a star is moving away from us so fast that the light waves stretch moving it up the spectrum, so up towards infared
how can you tell if an object is reflecting blue light from a star
A Doppler red-shift is a shift in recognizable features of a star's spectrum from the wavelengths where we know they belong toward longer wavelengths. Such a shift can be caused by the star's moving away from us, and that's how it's interpreted when astronomers see it. A Doppler blue-shift is a shift in recognizable features of a star's spectrum from the wavelengths where we know they belong toward shorter wavelengths. Such a shift can be caused by the star's moving toward us, and that's how it's interpreted when astronomers see it.
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.