5 galaxies in perfect alignment challenge our best model of the universe

[Admin]

Astronomers have discovered a group of dwarf galaxies with distinct features that challenge predictions made by the prevailing cold dark matter (CDM) model.

5 galaxies in perfect alignment challenge our best model of the universe : Read more

 

[Torbjorn Larsson]

I call foul. The paper itself does not discuss dark matter models.

And in fact their dwarf galaxy sample is an outlier in that all of them lack dark matter [fig. 4], indicating interaction with other galaxies. Moreover they don't try to estimate the likelihood of seeing the same rotational orientation, which is a slight statistical excess.

That e.g. cosmological dark matter filaments align galaxies and their angular momenta as they gravitationally stream along filaments towards the massive cosmic web nodes is a known phenomena.

Here we investigate the possibility that filaments of galaxies—cylindrical tendrils of matter hundreds of millions of light years across—are themselves spinning. By stacking thousands of filaments together and examining the velocity of galaxies perpendicular to the filament’s axis (via their redshift and blueshift), we find that these objects too display vortical motion consistent with rotation, making them the largest objects known to have angular momentum. The strength of the rotation signal is directly dependent on the viewing angle and the dynamical state of the filament. Filament rotation is more clearly detected when viewed edge-on. In addition, the more massive the haloes that sit at either end of the filaments, the more rotation is detected. These results signify that angular momentum can be generated on unexpectedly large scales.

https://www.nature.com/articles/s41550-021-01380-6

 

[Catastrophe]

The number of galaxies in the universe is estimated to be between hundreds of billions and two trillion:

• 100–200 billion galaxies
  This estimate is based on multiplying the number of galaxies in a small patch of sky by the number of times that patch would fit in the entire sky.
  
  
  
• 2 trillion galaxies
  This estimate is based on computer simulations that match what telescopes see with estimates of how many more galaxies might be there. However, a 2021 study using data from NASA's New Horizon's spacecraft suggests that the number of galaxies is more likely in the hundreds of billions.
  
  
  

The heading states "perfect alignment" but the article says "unusually aligned in a near-straight" line.

Furthermore, with hundreds of billions of observable galaxies, is it any wonder that 5 are in a near-straight line?

Cat