Measuring Galactic Rotation: How & What We Know

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SUMMARY

Galactic rotation is measured using the redshift of emission or absorption lines from gas, which reveals the velocity of stars in relation to their distance from the galactic center. Observations indicate that stars farther from the center exhibit velocities significantly higher than expected, leading to the conclusion that dark matter is a crucial factor in explaining these discrepancies. Research spanning nearly 90 years and thousands of galaxies supports these findings, despite the presence of measurement errors. Both our Milky Way and other galaxies are studied to understand these dynamics.

PREREQUISITES
  • Understanding of redshift and its application in astronomy
  • Familiarity with emission and absorption lines in spectral analysis
  • Basic knowledge of dark matter and its role in astrophysics
  • Awareness of galactic structure and dynamics
NEXT STEPS
  • Research the methods of measuring redshift in astronomical observations
  • Explore the concept of dark matter and its implications for galactic rotation
  • Study the techniques used in spectral analysis of emission and absorption lines
  • Investigate the historical context and evolution of galactic rotation studies over the past 90 years
USEFUL FOR

Astronomers, astrophysicists, and students of cosmology interested in understanding the dynamics of galaxies and the role of dark matter in galactic rotation.

PhDnotForMe
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TL;DR
How we measure galactic rotation
How have we been able to measure galactic rotation? I have seen graphs showing the relation between the velocity of stars in a galaxy and their distance from the center. These graphs show that the observed velocities of stars are much faster than they are expected to be, particularly ones that are farther from the center and they use dark matter to explain it. Do we look at our own galaxy or do we look at other galaxies? How are we so sure? Any links would be greatly appreciated.
 
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It can be measaured by using the redshift of the emission or the absorption lines that is coming from the gas.
PhDnotForMe said:
Summary: How we measure galactic rotation

Do we look at our own galaxy or do we look at other galaxies?
We do both ?
PhDnotForMe said:
Summary: How we measure galactic rotation

How are we so sure?
Why shouldn't we ?
 
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Arman777 said:
Why shouldn't we ?
Why should we ? -_-
 
Arman777 said:
It can be measaured by using the redshift of the emission or the absorption lines that is coming from the gas.

Nice
 
PhDnotForMe said:
Nice
I find this nice site that explains it in more detail
http://www.astronomy.com/magazine/ask-astro/2018/05/rotational-speed-of-a-galaxy
PhDnotForMe said:
Why should we ? -_-
There are always some errors in these measurements but this research is done for almost 90 years and for thousands of galaxies.

Do you have any opinion about what could be wrong with these measurements ?
 
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Arman777 said:
I find this nice site that explains it in more detail
http://www.astronomy.com/magazine/ask-astro/2018/05/rotational-speed-of-a-galaxyThere are always some errors in these measurements but this research is done for almost 90 years and for thousands of galaxies.

Do you have any opinion about what could be wrong with these measurements ?
Nope, was just curious on the actual method. Thanks for the link! You've been helpful:)
 
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