Dark matter not found in globular clusters orbiting MilkyWay

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SUMMARY

The discussion centers on the absence of dark matter in globular clusters orbiting the Milky Way Galaxy, as highlighted by Steven Novella on the podcast “Skeptics Guide to the Universe.” Participants clarify that globular clusters and satellite galaxies can be distinguished visually, negating the need for dark matter as a differentiating factor. The conversation raises critical questions about the measurement of dark matter in globular clusters, emphasizing the challenge of quantifying a hypothetical entity by subtracting visible mass from total mass.

PREREQUISITES
  • Understanding of dark matter and its gravitational effects
  • Familiarity with globular clusters and satellite galaxies
  • Basic knowledge of astronomical measurement techniques
  • Awareness of the current theories surrounding dark matter
NEXT STEPS
  • Research the methods for measuring dark matter in astronomical bodies
  • Explore the differences between globular clusters and satellite galaxies
  • Study the implications of dark matter's absence in certain celestial structures
  • Investigate current experimental approaches to understanding dark matter
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Astronomers, astrophysicists, and students of cosmology interested in the properties and implications of dark matter in relation to globular clusters and satellite galaxies.

Gordon Potter IV
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On the podcast “Skeptics Guide to the Universe”, host, Steven Novella mentioned that astronomers can tell the difference between globular clusters orbiting the Milky Way Galaxy and satellite galaxies by looking to see if there is the gravitational effects of dark matter. Why would this be? That there is no dark matter in GC’s orbiting MW but satellite galaxies do? And isn’t this a good clue as to what dark matter may be or at least eliminate some ideas? I was unable to find any further info online, and thought this might be the right place to learn more.
Thank you
 
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Welcome to PF.

'Dark matter' is a placeholder name for stuff which has mass like normal matter, but is not visible.
That is, it does not interact with the electromagnetic field
Enough dark matter though produces gravitational effects which have been observed.
We don't know what it is, but it's being worked on experimentally.
The wiki summary is OK.
https://en.wikipedia.org/wiki/Dark_matter
 
Last edited:
Gordon Potter IV said:
On the podcast “Skeptics Guide to the Universe”, host, Steven Novella mentioned that astronomers can tell the difference between globular clusters orbiting the Milky Way Galaxy and satellite galaxies by looking to see if there is the gravitational effects of dark matter. Why would this be?

Hi there
welcome to PF :smile:


Sorry, but that's rubbish ... globulars and galaxies are very different looking visually ... you don't need to use any other exotic method to distinguish their difference, like that guy is suggesting

regards
Dave
 
Last edited:
davenn said:
Hi there
welcome to PF :smile:


Sorry, but that's rubbish ... globulars and galaxies are very different looking visually ... you don't need to use any other exotic method to distinguish their difference, like that guy is suggesting

regards
Dave

That does not answer Gordon Potter IV's question the way I read it. Why do globular clusters lack dark matter?

I'll add the further question, "how accurately can you measure the dark matter in a globular cluster?"
 
stefan r said:
That does not answer Gordon Potter IV's question the way I read it. Why do globular clusters lack dark matter?

That wasn't the Q

this was ...

On the podcast “Skeptics Guide to the Universe”, host, Steven Novella mentioned that astronomers can tell the difference between globular clusters orbiting the Milky Way Galaxy and satellite galaxies by looking to see if there is the gravitational effects of dark matter. Why would this be?

he never stated
Why do globular clusters lack dark matter?
that is YOUR statement
 
stefan r said:
I'll add the further question, "how accurately can you measure the dark matter in a globular cluster?"

how can you measure something, that is still hypothetical ... accurately or otherwise ?
 
By measuring the total mass and subtracting the mass of the stars.
 
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