Can anyone explain me what is the redshift?

Question

redshift with the nebulas/nebulae

Answer 1

It got to do with Doppler Effect. If an object is moving towards you, the light you see from the object is shifted to a shorter wavelength (blueshift). If it is moving away from you, the light you see from the object is shifted to a longer wavelength (redshift).

Answer 2

There have been several good answers explaining what the doppler shift is and how it works. Your question, however asked what the redshift was and so I assume you are referring to the redshift as it pertains to Hubble and the expanding universe.

Allow me to elaborate on what others have already explained....

The universe is about 75% hydrogen. Much of that hydrogen is in stars and those stars shine with light resulting from fusion. If you've read many of these answers, then you have probably already gotten a good idea of how that happens so we won't rehash that here.

Any time a hot gas is under pressure as it is in a star, it emits a continuous spectrum, usually in the form of what we often refer to as white light. By this I mean that it contains all the colors, both visible and invisible.

Each element in the universe has a certian fingerprint that shows up in these spectrums. The most famous and common are the Hydrogen Blamer Lines. These are thin black lines that show up in the spectrum when hydrogen is present. Why they show up is another story having to do with energy absorption and if you are interested in that, then feel free to post another question. What is important here, however, is that they always show up in the same colors at the same frequency and wavelengths when the source of the light is not moving.

Now when the source of that light is moving, either towards or away from you, the those Blamer Lines will shift a little towards the blue or towards the red. This is the result of the doppler shift and others have adequately explained this phenomenon. I would only add that the more those lines are shifted, the faster the object is moving.

It was when Hubble observed the Balmer Lines of hydrogen being shifted dramatically to the red side of the spectrum of virtually all the distant galaxies that he came to the conclusion that the universe was expanding. The additional conclusion was that if the universe was expanding now, then it must have at one point been much more contracted, and this led to the Big Bang concept.

So, as you can see, the "redshift" was the observation that directly led to the supposition that the universe was expanding and also that the universe began with the Big Bang.

Answer 3

When the light an object emits is displaced toward the red end of the spectrum it is said to be redshifted. In general, photons of light that are emitted at a source at one energy and detected by an observer at a lower energy are redshifted. Often, the redshift of an object can be measured by examining atomic absorption or emission lines in its spectrum. Redshifts can be caused by the motion of a source away from an observer. For distant objects, redshifts can be caused by the expansion of the Universe.

Answer 4

In physics and astronomy, redshift is a phenomenon in which the visible light from an object is shifted towards the red end of the spectrum. Scientifically, it is an observed increase in the wavelength and decrease in the frequency of electromagnetic radiation received by a detector compared to that emitted by the source. The corresponding shift to shorter wavelengths is called blueshift.

For visible light, red is the color with the longest wavelength, so colors experiencing redshift shift towards the red part of the electromagnetic spectrum. The phenomenon goes by the same name even if it occurs at non-optical wavelengths (e.g. gamma rays, x-rays and ultraviolet). At wavelengths longer than red (e.g. infrared, microwaves, and radio waves) redshifts shift the radiation away from the red.

Redshift typically occurs when a light source moves away from an observer, analogous to the Doppler shift which changes the frequency of sound waves. While observing this redshift has a number of terrestrial uses (e.g. Doppler radar and Radar guns), it is famously employed in astronomy where it is used as a diagnostic in spectroscopic astrophysics to determine information about the dynamics and kinematics (i.e. movement) of distant objects. This redshift phenomenon was first predicted and observed in the nineteenth century as scientists began to consider the dynamical implications of the wave-nature of light. There is also a gravitational redshift which occurs due to the time dilation that occurs in general relativity near massive objects. Most famously, redshifts are observed in the spectra from distant galaxies, quasars, and intergalactic gas clouds to increase proportionally with the distance to the object. This is generally considered to be one of the major forms of evidence that the universe is expanding, supporting the Big Bang model.

Answer 5

Babylon English-Hebrew

redshift
(ש"ע) תנועה לכיוון אורכי הגל הארוכים





Britannica Concise Encyclopedia

redshift

Displacement of the spectrum of an astronomical object toward longer wavelengths (visible light shifts toward the red end of the spectrum).

In 1929 Edwin Hubble reported that distant galaxies had redshifts proportionate to their distances (see Hubble's constant). Since redshifts can be caused by motion of an object away from the observer (the Doppler effect), Hubble concluded that all galaxies are receding from each other. This became the cornerstone of theories of an expanding universe.



© 2005 Encyclopædia Britannica, Inc.



Merriam-Webster Collegiate® Dictionary

red·shift
Pronunciation: 'red-'shift
Function: noun
Date: 1923

: a displacement of the spectrum of a celestial body toward longer wavelengths that is a consequence of the Doppler effect or the gravitational field of the source also : a measurement of a celestial body's redshift equal to the ratio of the displacement of a spectral line to its known unshifted wavelength and used especially to calculate the body's distance from earth
–red·shift·ed adjective



© 2005 Merriam-Webster, Incorporated


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Answer 6

Redshift is a Doppler shift to longer wavelength, lower frequency light caused by the light source moving away from you. Lower frequency light is redder and higher frequency light is bluer. An object moving toward you would look bluer. A similar effect happens with sound. As the sound source approaches you it is Doppler shifted to shorter wavelengths and higher frequency, which is a higher pitched sound, and as it moves away it makes a lower pitched sound. That is why a car speeding past you makes that zeeeeeoooouuuuuummmm sound as it passes.

So why doesn't the car look bluer approaching and redder going away? Because the speed has to be a large fraction of the speed of the waves. Sound waves move at 600 miles per hour so a car moving at 60 miles per hour is at 10% the speed of sound and the Doppler shift is easily heard. To make an easily seen optical Doppler shift would require moving at 10% the speed of light, which would be about 70 million miles per hour. The Doppler shift for light of a car is enough to measure with modern electronics though. Police radar uses Doppler shift of radio waves, which are just very low frequency light waves, to measure your speed and maybe give you a ticket!

Answer 7

I requested 2 questions that were very resembling yours. even with the undeniable fact that, i did not get solutions as stupid as you purchased. i ask your self why it quite is? be conscious how those human beings declare there are 'different factors', yet they don't problem to inform us what they're. yet another different technique is to attempt distraction, inclusive of asking the position the flexibility got here from in the first position. I also like the "it really is no longer a regulation" actuality, even even with the undeniable fact that redshift might want to be anticipated and measured. Redshift is likewise be measured in the indicators we get carry of from our own GPS satellites! The redshift/blueshift equations are used through your GPS receiver to ascertain your region and speed. i think asking the vast Bang deniers to describe the data is a surprising thanks to prepare their dishonesty. The creationists were able to go back up with option factors for the data of evolution (unbelievable as they're), even with the undeniable fact that the vast Bang deniers won't be able to even pretend to furnish their own explaination for redshift and CBR. per chance i visit ask my questions each so regularly, basically to make certain what occurs.

Answer 8

When an light is moving towards you, the wavelength gets shortened and you get Blue shift. However, when it is moving away from you, the wavelength gets longer, and you see Red shift. This is essentially the Doppler's effect. By detecting the degree of shift, one can determine the speed that the object is moving.

A similar phenomenon happens with Sound. When a motorcycle passes you at high speed, you will here "Vaaa........Rooommm".
The "Vaaa..." is higher frequency and the "Rooommm" is the lower frequency.

Answer 9

The red shift is the reduction in frequency of light waves from objects receding from us. The speed of light is constant no matter the velocity of the object that emits it. So if the object is moving away from us the light from it can't drop to a sub light speed. Instead the frequency drops and causes it to shift to a lower place in the spectrum. It's much the same for sound. The best example is a train speeding toward you has a certain pitch. As the train passes you the pitch drops dramatically to a lower frequency. The phenomenon is much the same for electromagnetic waves or sound waves.

Answer 10

to a longer wave length bcoz of lots of reasons specify the area u r working