Detecting a Dipole in the Handedness of Spiral Galaxies at Redshift z ~ 0.04

In summary, Michael Longo of the University of Michigan has found evidence of a preference for right or left handedness in spiral galaxies, with left-handed spirals appearing more frequently in the northern hemisphere and right-handed spirals in the southern hemisphere. This apparent "parity asymmetry" does not violate homogeneity but does raise questions about isotropy. The alignment of these rotation axes with the mysterious cold spot in the cosmic microwave background is a controversial claim and requires further evidence to support it.
  • #1
bcrowell
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Longo, "Detection of a Dipole in the Handedness of Spiral Galaxies with Redshifts z ~ 0.04," 2011, http://arxiv.org/abs/1104.2815

If this is right, then I guess it would be the first possible hint of a nonzero rate of rotation for the universe. He doesn't attempt to state his results in terms of an angular velocity. I doubt that this type of anisotropy is consistent with inflation...?

For background, see our FAQ on this topic: https://www.physicsforums.com/showthread.php?t=506988
 
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http://www.technologyreview.com/blog/arxiv/23410/

FWIW, Longo seems to think the spin axes might line up with the cold spot in the CMB.

"Michael Longo at the University of Michigan has long been searching for another asymmetry--a preference for right or left handedness in spiral galaxies. And he says he's found it, previously in an analysis of over 2600 nearby spiral galaxies and now in an analysis of 15,000 more.

The evidence seems to indicate that left handed spirals are more common in the northern hemisphere, above the northern galactic pole. And although the signal is less strong, right-handed spirals appear more frequently in the south.

What's more, Longo says the axis of this alignment points directly towards the mysterious cold spot in the cosmic microwave background, which was discovered in the southern hemisphere in 2004."


Respectfully submitted,
Steve
 
  • #3


Ben, I'm astounded no one has yet commented on this thread.

If I'm reading Longo correctly, he seems to be saying that galaxies in our northern galactic sky rotate differently than those in our southern galactic sky. Which would put us in the middle. He says "parity asymmetry", but it seems overtly anti-Copernican to me. Please correct me if I'm wrong.

Thank you,
Steve
 
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  • #4


Dotini said:
If I'm reading Longo correctly, he seems to be saying that galaxies in our northern sky rotate differently than those in our southern sky. Which would put us in the middle. He says "parity asymmetry", but it seems overtly anti-Copernican to me. Please correct me if I'm wrong.

I think it only violates isotropy, not homogeneity. If all galaxies rotate in the same direction, then an observer in the middle of them sees them as clockwise in half of the sky and counterclockwise in the other. It's like standing behind a clock whose face is made out of glass -- the hands appear to go counterclockwise from that perspective.

Of course the real question is whether it's right. Personally I'd consider it an extraordinary claim that requires extraordinary evidence.
 
  • #5


Could there be local measurements that don't accord to a more global model? Caution is advised, IMO.
 
  • #6


I agree with bcrowell, extraordinary evidence is required to prove this is not just a selection effect or random anomaly. The claim rotation axes are aligned with the CMB 'cold spot' sets off my crank alarm. It looks like statistical snake oil to me.
 

1. What is a dipole in the handedness of spiral galaxies?

A dipole in the handedness of spiral galaxies refers to a pattern or trend in the rotation direction of these galaxies. It is based on the concept of chirality, which is the property of an object that distinguishes it from its mirror image. In the context of spiral galaxies, this means that the majority of them rotate in either a clockwise or counterclockwise direction, creating a dipole-like structure.

2. How is this dipole detected?

This dipole can be detected by observing the polarization of light emitted by the galaxies. The polarization of light is affected by the rotation direction of the galaxy, and by measuring the polarization of a large number of galaxies, a pattern can be identified and the dipole can be detected.

3. What does the redshift z ~ 0.04 refer to?

The redshift z ~ 0.04 is a measure of the distance to the galaxies being studied. It is a dimensionless quantity that represents the amount of stretching or shifting of light emitted by the galaxy due to the expansion of the universe. A redshift of z ~ 0.04 means that the galaxy is about 200 million light-years away.

4. Why is this study important?

Studying the dipole in the handedness of spiral galaxies can provide valuable insights into the formation and evolution of these galaxies. It can also help us understand the larger-scale structures and dynamics of the universe. Additionally, it can provide evidence for the existence of dark matter, as the dipole may be influenced by the gravitational pull of this elusive substance.

5. What are the potential implications of the results from this study?

The results from this study could have implications for our understanding of the fundamental laws of physics and the origin of the universe. If a dipole in the handedness of spiral galaxies is confirmed, it could provide evidence for the existence of a preferred direction in the universe, which could challenge some of our current theories and models. It could also lead to further research and investigations into the nature of dark matter and its role in shaping the structures of the universe.

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