Redshift & Blueshift: Is There a Consensus?

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    Blueshift Redshift
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Discussion Overview

The discussion revolves around the concepts of redshift and blueshift in astronomy, specifically questioning whether there is a consensus on the percentage of each type of shift observed in celestial bodies. Participants explore the implications of these shifts in the context of cosmic expansion and local galactic movements.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant questions if there is a consensus on the percentage of redshift and blueshift readings, indicating a lack of clarity on the topic.
  • Another participant emphasizes the need for specificity, noting that measurements of redshift are primarily associated with cosmological expansion, while local motions can affect blueshift readings.
  • A novice participant seeks to understand if there are large celestial bodies other than the Andromeda galaxy that are approaching the Milky Way, or if most are receding.
  • Some participants suggest that there are at least two other galaxies approaching the Milky Way, indicating that local dynamics may differ from the general trend of expansion.
  • Links to external resources are provided to explore blue-shifted objects and local group dynamics further.
  • One participant mentions that the Milky Way is already colliding with another galaxy and that several more are on a collision course, contrasting with the general expansion of the universe.

Areas of Agreement / Disagreement

Participants express differing views on the specifics of redshift and blueshift measurements, with no consensus reached on the overall percentages or the implications of these shifts for local versus cosmic scales.

Contextual Notes

The discussion highlights the complexity of measuring redshift and blueshift, with factors such as local galactic interactions and the nature of cosmic expansion influencing interpretations. There are unresolved questions regarding the exact nature and percentage of these shifts.

Who May Find This Useful

Astronomy enthusiasts, students of astrophysics, and individuals interested in cosmic dynamics and galactic interactions may find this discussion relevant.

LocktnLoaded
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Since we have been taken readings of redshift, blueshift for sometime now, is there a consensus on a percentage of each?
 
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You need to be a LOT more specific. If you mean measurements of cosmological expansion, all measurements are redshifted. If you mean the local volume, then they are dependent on local motions and I don't know the mix.

What are you asking?
 
novice at astronomy

In short I guess what I'm trying to ask is , besides the Andromeda galaxy, are there any other large bodies coming our way, or are they all expanding outward from us?
 
I believe there are at least another two galaxies approahing us.
They are fairly local.
You could try NASA site or NED, to ask your question.
 
Last edited by a moderator:
http://nedwww.ipac.caltech.edu/cgi-bin/nph-allsky?ra_constraint=Unconstrained&ra_1=&ra_2=&dec_constraint=Unconstrained&dec_1=&dec_2=&glon_constraint=Unconstrained&glon_1=&glon_2=&glat_constraint=Unconstrained&glat_1=&glat_2=&z_constraint=Less+Than&z_value1=0&z_value2=&z_unit=km%2Fs&ot_include=ANY&ex_objtypes1=Clusters&ex_objtypes1=Supernovae&ex_objtypes1=QSO&ex_objtypes2=AbsLineSys&ex_objtypes2=GravLens&ex_objtypes2=Radio&ex_objtypes2=Infrared&ex_objtypes3=EmissnLine&ex_objtypes3=UVExcess&ex_objtypes3=Xray&ex_objtypes3=GammaRay&nmp_op=ANY&out_csys=Equatorial&out_equinox=B1950.0&obj_sort=RA+or+Longitude&zv_breaker=30000.0" lists 2189 blue-shifted objects.
 
Last edited by a moderator:
LocktnLoaded said:
In short I guess what I'm trying to ask is , besides the Andromeda galaxy, are there any other large bodies coming our way, or are they all expanding outward from us?

Seems that the Milky Way is already colliding with another galaxy and there are a few more on the way.
http://curious.astro.cornell.edu/question.php?number=386

The Andromeda galaxy collision will just be much more significant.

The Milky Way is part of a "Local Group" of galaxies which are not expanding away from each other (galaxies tend to be found in clusters).
http://www.seds.org/messier/more/local.html
 
Last edited by a moderator:

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