Questions tagged [redshift]
Redshift refers to the difference in frequency of an electromagnetic wave as measured by a source versus a receiver in relative motion.
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When light gets red shifted by the expending universe it's energy decreases. What happens to that energy? [duplicate]
If a Photon of light is red shifted its wavelength increases and therefore its energy decreases. What happens to that energy as energy should be conserved right?
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Electromagnetic energy-momentum tensor with allowance for gravitational redshift
Is there an electromagnetic energy-momentum tensor that takes into account the gravitational redshift? If so, what does it look like and where can I read more about it?
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Keck versus Webb: discrepancies in the redshift measurements of the galaxy GN-z11 (the most distant galaxy discovered with the Hubble Space Telescope)
Two years ago Nature Astronomy published a paper based on measurements from the Keck Telescope stating that the redshift of the galaxy GN-z11 (discovered by Hubble) is:
$$ z=10.957 \pm 0.001 $$
Source:...
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Energy conservation in the redshifted light by expansion of the universe [duplicate]
I asked chat-gpt the same question, and this is her answer:
The energy of light that is redshifted due to the expansion of the universe doesn't disappear, it is simply transformed into other forms of ...
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Does the Doppler effect work either way?
I know that the Doppler effect is when waves get compressed or stretched. For light this causes red shifts and blue shifts. My question is if we were moving towards or away from the source of light, ...
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How would the Redshift of a Photon be influenced if it travels through a volumetric gas disk?
so me and a buddy have been working on a Black Hole render engine for quiet a while now. And at this point we have most of the technical stuff worked out. Which results in images like these;
Note, ...
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Different definitions of recession velocity
I have encountered two definitions of recession velocity that seem to refer to different concepts, but I am wondering whether the two are actually the same.
Definition 1
If we denote the scale factor, ...
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Blueshift caused by dark energy?
Galaxies that are sufficiently far away from our point of view are receding from us due to the accelerated expansion of the universe (supposedly caused by dark energy) and therefore their light is ...
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Doesn't the increase in redshift of galaxies over larger distances mean that the expansion of the universe is slowing down? [duplicate]
This question seems too simple to not have been asked, but I cannot seem to find an explanation. So apologies if this is a duplicate.
The current explanation for the expansion of the universe as I ...
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Distance $r$ between galaxies inside the galaxy cluster
I am currently working on the dynamics of the galaxy cluster, so i am trying to get the distance $r$ between the galaxies inside the galaxy cluster from its centre. As a input i have RA , DEC and Z ...
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Frequency shift of photon using magnetic field
According to GR, it is possible to redshift the frequency of a photon using a magnetic field as demonstrated by the Gerstenshtein Effect:
https://web.archive.org/web/20210225134450/http://jetp.ac.ru/...
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Calculating distance to galaxies seen through a telescope
When we see a galaxy through a telescope, say the James Webb telescope, it is said we see a galaxy as much as about 10 billion light years away. But 10 billion years ago we were much closer (because ...
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Mapping photoluminescense spectra based on their peak
Do you know any program that can map multiple spectra? To be more specific, I have a lot of spectra that show the emission peak wavelength of a material in different locations of its surface. It can ...
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Applications of relativistic, but non-gravitational, redshift
I am trying to find real-world applications or experiment of the special relativity redshift, where any gravitational effect can be neglected. That is, when
$$
\frac{\lambda_\text{observed}}{\lambda_\...
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Redshift and expansion and time
From the Weinberg 1972 book Gravitation and Cosmology Principles, we have the following ($R(t)$ is the scale factor):
I understand everything, except the first part of equation (14.3.4), how does the ...
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Interval at time of emission and observation between two photons
In deriving how scale factor is related to redshift $1 + z = \frac{1}{a(t_e)}$, we started by saying the first light wave obeys:
$c\int^{t_o}_{t_e}\frac{dt}{a(t)} = r$, where r is comoving distance.
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Proper distance in terms of the deceleration parameter
So, in an effort to connect theory to measurable quantities, in the Ryden cosmology textbook the scale factor is Taylor expanded as $$a(t) \approx 1 + H_o (t-t_o) - \frac{1}{2}q_o H^2_o (t-t_o)^2$$ ...
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Wrong scale factor on wikipedia
From wikipedia we have for Scale-Factor $a(t)$:
".. two galaxy clusters, moving with the Hubble flow in an expanding or contracting FLRW universe at any arbitrary time "t" to their ...
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What happens to the energy of the photon in the red shift? [duplicate]
In Doppler or Hubble red shift, the wavelength reached us is longer than the original wavelength, as a result, according to the Planck relation, its energy has decreased. Where does this energy go? ...
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Blushifted receding objects in an accelerating expanding universe?
I found this article (https://arxiv.org/abs/astro-ph/0104349) which apparently shows that there can be blue-shifted objects in an expanding universe.
However, it is not clear to me whether this would ...
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Are Photons Entangled with Gravity? [closed]
Part 1: A photon's wavelength is red-shifted by expanding space. Since $E=hf$ the photon imparts some of it's energy to the curvature of space, slowing the expansion of space ever so slightly. Is that ...
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How can you determine distances to obejcts further away than 13.72 billion light years?
I was checking out this calculator where you can calculate distance to distant astronomical objects from redshift.
Here are some values:
z=0.1 > distance (light travel time) 1.31 billion lightyears
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Why galaxies with a redshift > 2 have a lower velocity now, compared to when the light was emmited?
I was playing around with astropy cosmology data, and I made the following graph:
On the x axis I plotted Redshift, and on the y axis the speed of light as 1c, 2c etc.
Until a redshift of ~ 2, my ...
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Is photon redshifted if observer starts moving away after photon is released
A. A light source and an oberserver are stationary relative to each other. The source emits a photon and the observer measures the wavelength.
B. A light source and an observer are stationary ...
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Hypothetically, according to the Standard Model, if the universe were not expanding, could we not cut out the Big Bang and inflation?
Hypothetically, according to the Standard Model, if the universe were not expanding, could we not cut out the Big Bang and inflation and begin the universe in an expanded state and still get the same ...
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Redshift and luminosity
Consider a flat FLRW Universe where the scale factor is $a = (t_0/t)^{2/(3+3w)}$. For a given redshift $z$, in which universe, $w=0$ or $w=1/3$ would a star appear brighter?
I am trying to solve this ...
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Too many low redshift galaxies in NED database
When using the NED database I found there are too many galaxies with very low redshift (Near zero). I used NEDs search by parameters function to find all galaxies within Z=0 to Z=.03 redshift. I did ...
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Proof of double Doppler shift
We know that the Doppler effect for EM radiation is $\Delta$$f$ = $\frac{v}{c}$$f_0$
$\Delta$$f$ = the change in frequency
v = the relative speed of the source and observer
c = the speed of light in a ...
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Supernova Observation and Hubble Parameter
“Their observations measured the evolution of the Hubble parameter over time by constructing a Hubble diagram: a plot of distance modulus versus redshift (Figure 11.33). For small $z$, the Hubble ...
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Is gravitational redshift measurable from a spacecraft observing an earthbound laser?
Aside from the calculation, the specific scenario for which I have no sense of the solution is the following:
The equivalence principle proposes a parallel between the force experienced by an ...
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Cosmological redshift in static universe [duplicate]
Can cosmological redshift be explained in a static universe?
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Would a telescope travelling at close to the speed of light be able to make better images because the object would be nearer (Lorentz contraction)?
The Lorentz contraction means that when you fly toward (or away from) a distant object, that object becomes less distant in your frame of reference. So if a telescope were flying towards a distant ...
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Is a photon redshifted differently depending on whether it is passing inside a galaxy or in a cosmic void?
Consider two photons that are emitted in different directions from the same source in the Milky Way, a long time ago (redshift $z_i$.) One of the photons leaves the galaxy, travels for, say, 50 Mpc, ...
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What's the definitive meaning of "redshift", as a quantity to be measured? [closed]
The recently supplied tag information on redshift states:
"Redshift typically refers to the difference between the frequency of an electromagnetic wave as ...
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How can gravity change the wavelength of a photon without the two peaks or troughs to accelerate one from the other?
How can gravity change the wavelength of a photon without the two peaks or troughs to accelerate one from the other? So is it possible that gravity accelerates light? Can the a certain wavelength ...
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How do we observe redshifted light from distant stars if the effect is not intrinsic to photons?
Derek from Vertasium says that wavelength and energy are not intrinsic properties of photons; they are properties of the photon-observer system. An observer in freefall in space will not observe ...
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How to account for signal transmission in measurements of beat frequency between separated senders?
An important technique in optics experiments is the determination of the beat frequency (a.k.a. beat note) between (optical, as good as monochromatic, suitably stable) signals of two senders; say, of ...
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Cosmological energy conservation
The expanding universe is gaining energy through increasing dark energy, and losing energy from red shift. Are these two effects comparable in magnitude?
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Wouldn't Miller's planet be fried by blueshifted radiation?
In Interstellar, wouldn't Miller's planet be fried by blueshifted radiation? The 61,000x time dilation multiplier would make even cosmic background radiation photons into extreme UV photons.
I was ...
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Which are the spectral lines used to calculate the redshift?
I'm not sure if this is correct but I read in an article that the light of a distant star is first passed through a tube containing hydrogen gas and then through the prism for getting the absorption ...
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How is the light from distant stars obtained on a prism for calculating redshift?
Redshift has been used to map the expanse of the universe but what mechanism do scientists use to obtain and single out the light from a galaxy millions of light years away on a prism for getting the ...
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Is it possible to visualise red shift?
If a picture of a star or galaxy hurtling away from Earth is taken, does it appear red despite it being a different colour? Would a blue coloured star moving away from us appear red to us or vice ...
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Is redshift an accurate method for measuring distances of distant galaxies and quasars?
I'm currently in 11th grade working on a science project about measuring distances using redshifts. I understand how the wavelength of a light wave increases when an object moves away from the point ...
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Why is the age of the universe $=D/v$, despite that $v$ is not constant with time?
I am watching a series of lectures by the Noble prize laureate Brian Schmidt and Paul Francis and in this episode (at 4:20) they make the simple assumption that a galaxy receding from us due to the ...
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Does the relative speed of light, or just the frequency of light, change near a planet?
I have read this this question that describes the red shift in frequency of light near a large planet. I'm wondering if the light will actually reach me slower.
Imagine that we have two lasers 1,000,...
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What is the “conspiratorial anisotropy” if we would see no star redshifts in one direction of the sky? [closed]
Suppose we see no redshift of stars in one direction only (or better, in directions on a small patch around it). And suppose in that direction (on a patch of sky around it) we see a lot more stars ...
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Mass of cosmologically distant object in Earth frame
The original paper on GW 150914 in PRL 116,06112 (2016), talks about black hole masses in the source frame and the detector frame, indicating that the black hole masses in the detector frame are ...
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How to calculate the redshift of reionization?
I am trying to calculate equalities given Omega parameters.
For example given, $\Omega_L = 0.6889083, \Omega_M = 0.311, \Omega_R = 9.17$ x $10^{-5}$ and $\Omega_K = 0$
$H_0 = 67.7$ km/sec/Mpc
The ...
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Redshift Due to Expanding Space (not increasing distance) [closed]
Please NOTE: "For example, a question that proposes a new concept or paradigm, but asks for evaluation of that concept within the framework of current (mainstream) physics is OK."
And: "...
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Cosmological time-dilation caused redshifting and photonic energy: Are Photon’s Energies Changed by Relativistic Transformations?
Amateur here, so go easy.
Given that cosmological time-dilation is the only GR-consistent reading of cosmological redshifting due to the accelerated expansion of space (due to the constancy of the ...
