- #1
Buzz Bloom
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- TL;DR Summary
- I am assuming that there is a database somewhere listing all of the galaxies which astronomers have found. If that is correct, my question is:
What fraction of these galaxies have a distance from Earth value associated with it?
Summary: I am assuming that there is a database somewhere listing all of the galaxies which astronomers have found. If that is correct, my question is:
What fraction of these galaxies in the database have a distance from Earth value associated with it, other than a distance based only on the value of z using a standard value for H0?
My guess is that it is a small fraction since for most of them a special kind of supernova must be detected whose brightness curve enables a calculation of distance D independent of z. My curiosity about this is from an idea I have that it might be possible to use all (or most of) the galaxies in the database knowing only the z values for the galaxies to calculate the radius of curvature of the universe.
I am also guessing that only galaxies with a value for z, and a value D which is not based only on z (using H0), are used to calculate the values for the five universe model parameters: h0 and four Ωs.
What fraction of these galaxies in the database have a distance from Earth value associated with it, other than a distance based only on the value of z using a standard value for H0?
My guess is that it is a small fraction since for most of them a special kind of supernova must be detected whose brightness curve enables a calculation of distance D independent of z. My curiosity about this is from an idea I have that it might be possible to use all (or most of) the galaxies in the database knowing only the z values for the galaxies to calculate the radius of curvature of the universe.
I am also guessing that only galaxies with a value for z, and a value D which is not based only on z (using H0), are used to calculate the values for the five universe model parameters: h0 and four Ωs.
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