All Questions
Tagged with distances hubble-constant
8 questions
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How much does a mile stretch in my lifetime due to cosmic expansion?
I've wanted to figure this out since I was a kid. Cosmic expansion is very small locally, and I was trying to get an appreciation for it.
How much would the mile expand in 80 years if the electrons in ...
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With 42 supernovae in 37 galaxies, how do we know SH0ES results is robust?
SH0ES is a collaboration that's anchoring the cosmic distance ladder by matching Cepheid data with Type 1a supernovae. Both of these are standard candles, so if we know the distance to a particular ...
- 4,861
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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 ...
user54537
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What is Hubble's parameter/constant H0 supposed to mean, exactly? [duplicate]
Surely it must mean that every second each Mpc expands by that much. Well what else, could it be.
So if the expansion is accelerating, then how can H0 be decreasing!?
Let's look at Hubble's law: v=H0D,...
user54537
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What exactly is the estimated distance to a far-off object when they say '50 Mpc/h' or '50 Mpc h^-1'? Is it less than 50 Mpc? Do you ÷ by 67 or 74?
Several recent arxiv.org papers I read mention distances to very distant objects in Mpc (megaparsecs) divided by Hubble's 'constant'....
Does that mean we should divide the Mpc or Gpc (gigaparsecs) by ...
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Calculating the present comoving distance or light travel distance of distant objects when only one value is given?
I was wondering how to calculate either the present comoving distance or the light travel distance when the source material only gives one value?
Is there and an online calculator or simple equation ...
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Question from Introduction to Modern Cosmology by Andrew Liddle
The exact question goes like this:
In the real Universe the expansion is not completely uniform. Rather, galaxies exhibit
some random motion relative to the overall Hubble expansion, known as their
...
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Did Gaia actually generate complete light curves for 212 Cepheids in other galaxies?
The recent BBC news item Gaia clocks speedy cosmic expansion says that a recent Gaia measurement of 212 Cepheid variables in other galaxies within the local group yields a Hubble constant of ~73 km/s/...
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