Questions tagged [redshift]
Questions related to the phenomenon whereby electromagnetic radiation (such as visible light) generated by an object moving away from an observer will have increase in wavelength (i.e. shifted toward the red end of the spectrum) once it reaches the observer.
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CMB redshift used to determine the difference in aging between the two inertial observers
If CMB redshift tells us our cosmological time dilation and we have two inertial observers in relative motion, who measure slightly different CMB redshift at the direction of their motion relative to ...
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How can you calculate the distance to an object knowing its cosmological redshift? (without Hubbles law)
Given some redshift z, how do we find the distance using the cosmological red shift formula (and presumably the Friedmann equations)? a = 1/(1+z), and we can assume that omega_0 = 1. I know a ...
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Why would some sources in a cross-matched DESI/SDSS catalog have different spectroscopic redshifts?
I've crossmatched quasars from DESI DR9 and from SDSS DR16. When I plot the spectroscopic redshift from each of the individual catalogs for each source, I get:
Naively, I'd expect the $z_{spec}$ to ...
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Using prospector for jwst data
I am working with JWST data. I want to estimate the redshift of the sources I have identified with SEXtractor with the help of prospector. Can somebody guide me in this?
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Could we (Earth, Humanity, Solar System) be falling into a black hole?
With the expansion of the universe, all objects far away from us appear to be moving away (ie: exhibit Redshift). With distance, this acceleration / redshift also seems to increase (~73,000 (m/s) / (...
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Approximate conversion of redshift 'z' to a time and/or distance, when reading papers?
I'm looking for some form of "rough and ready" formula to convert between redshift z value, years since BB, and distance, so that when I read an astronomy paper and it discusses an event that occurred ...
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Redshift distance proportionality at high Z and need for "mighty mouse" galaxies?
Allegedly supported by some evidence from the new James Webb space telescope physicist Eric Lerner has written an article that have garnered some attention. He writes that:
"Put another way, the ...
CommunityBot
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How do we work out the light travel time on a cosmic scale?
I just read this article in the AUSTRALIAN SKY & TELESCOPE magazine, Nov/Dec 2022 Issue 140, on P16, KEEP YOUR DISTANCE: How far away are the objects we see in the universe? And on P23:
"And ...
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Does a cosmological redshift occur within our local group, of galaxies?
I know that it is not supposed to be expanding but space is space and it is expanding everywhere else outside it so why not inside it too, and gravity just holds everything back.
I suppose if it is, ...
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Shouldn't the Friedmann equation take into account the massive extra distance traveled during the time for gravity to travel across the universe? [closed]
I’ve got a question that has been bothering me for the past few years that of the few sources that are only somewhat related to this, none of them say anything about this should be wrong so I can’t ...
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Why are distant type Ia supernovae dimmer than expected?
Why are the (extremely) distant type Ia supernovae dimmer than expected?
Relative to what? Their cosmological red shift? Well, what else.
Please don't just say "Because the expansion is ...
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Why does a Decision Tree produce lines in photometric redshift predictions?
In this paper, the authors compare the speed and accuracy of various machine learning algorithms to produce photometric redshift estimates:
Why does the DT regressor put the estimates into bands ...
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Is the difference of redshift parameter z able to prove expansion is accelerating in flat FLRW universe model?
Sorry for my bad english, this is not my mother tongue.
Recently, I've encountered a problem in cosmology class that is about FLRW universe.
Assuming that the universe we inhabit is composed of non-...
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Are gravitational waves red-shifted?
Gravitational waves originate from significant distances. Presumably they are red-shifted the same amount as the galaxies they originated in. In the absence of gravitational “spectral lines”, can this ...
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JWST Early Black Holes: Gas Collapsed To Metallic Hydrogen Core?
I was reading an article about early black holes found by JWST at Redshift 9. And saw that there was wonder at how large amounts of gas could collapse into a black hole as a theory.
So my question is ...
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