a MOND theory that is not falsified by the CMB?

Discuss Astrophysics.
Post Reply
User avatar
notFritzArgelander
In Memory
In Memory
Articles: 0
Offline
Posts: 14925
Joined: Fri May 10, 2019 4:13 pm
4
Location: Idaho US
Status:
Offline

TSS Awards Badges

a MOND theory that is not falsified by the CMB?

#1

Post by notFritzArgelander »


this is going to need a deeper dive. one reason i've always discounted MOND theories is that they don't predict the CMB correctly. if this one does, (that's a very big IF) i may have to rethink my level of distaste for MOND. it's even relativistic! there's still the primordial lithium and gravitational lensing and Bullet Cluster observations, though, so massive distaste is still justified. on a scale of 10, i may cut my 11 back to 8 or 9. ;)

https://phys.org/news/2021-10-mond-theo ... owave.html
Skordis and Zlosnik suggest their model can be used to explain both gravitational lensing and data in the CMB. Up next, they plan to find out if it can also explain the universe's lithium abundance and discrepancies in measurements of the cosmic expansion rate—something dark matter theories have failed to do. They also note their ideas are also free of ghost instabilities.
it's also the first time these fatal failures of MOND are being addressed.

https://journals.aps.org/prl/abstract/1 ... 127.161302
We propose a relativistic gravitational theory leading to modified Newtonian dynamics, a paradigm that explains the observed universal galactic acceleration scale and related phenomenology. We discuss phenomenological requirements leading to its construction and demonstrate its agreement with the observed cosmic microwave background and matter power spectra on linear cosmological scales. We show that its action expanded to second order is free of ghost instabilities and discuss its possible embedding in a more fundamental theory.
i'll check arXiv after my Dr appointment.
Scopes: Refs: Orion ST80, SV 80EDA f7, TS 102ED f11 Newts: AWB 130mm, f5, Z12 f5; Cats: VMC110L, Intes MK66,VMC200L f9.75 EPs: KK Fujiyama Orthoscopics, 2x Vixen NPLs (40-6mm) and BCOs, Baader Mark IV zooms, TV Panoptics, Delos, Plossl 32-8mm. Mixed brand Masuyama/Astroplans Binoculars: Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker IV, Vixen Porta II, Celestron CG5
User avatar
notFritzArgelander
In Memory
In Memory
Articles: 0
Offline
Posts: 14925
Joined: Fri May 10, 2019 4:13 pm
4
Location: Idaho US
Status:
Offline

TSS Awards Badges

Re: a MOND theory that is not falsified by the CMB?

#2

Post by notFritzArgelander »


I've found the arXiv pdf:

https://arxiv.org/pdf/2007.00082.pdf

A first read through has been done. It needs another look before I comment.
Scopes: Refs: Orion ST80, SV 80EDA f7, TS 102ED f11 Newts: AWB 130mm, f5, Z12 f5; Cats: VMC110L, Intes MK66,VMC200L f9.75 EPs: KK Fujiyama Orthoscopics, 2x Vixen NPLs (40-6mm) and BCOs, Baader Mark IV zooms, TV Panoptics, Delos, Plossl 32-8mm. Mixed brand Masuyama/Astroplans Binoculars: Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker IV, Vixen Porta II, Celestron CG5
User avatar
notFritzArgelander
In Memory
In Memory
Articles: 0
Offline
Posts: 14925
Joined: Fri May 10, 2019 4:13 pm
4
Location: Idaho US
Status:
Offline

TSS Awards Badges

Re: a MOND theory that is not falsified by the CMB?

#3

Post by notFritzArgelander »


The paper opens by acknowledging the failures of previous attempts at making a relativistic MOND, RMOND.

It ignores laboratory findings that falsify the minimum acceleration parameter in MOND. That is a grave oversight. They require that their RMOND obey general covariance and the Einstein equivalence principle so this is good. Problems with gravity then violating Lorentz invariance (!!!) are then noted.

I would have regarded the theory as dead at that point because of observational limits on Lorentz violation. But they press on.

They show the stability of the theory and gravitational waves and lensing. Nowhere is the Bullet Cluster where lensing is happening where the matter isn't discussed, Nor are DM free galaxies addressed. The only advantage of this theory over previous attempts at a relativistic MOND is that the Sun doesn't collapse gravitationally in two weeks time. That is all to the good. The above problems are all to the bad.

If they manage to deal with Li abundance and structure formation that will be good too. But the above problems need handling also.

Instead of my opposition to MOND dropping from 11/10 to 8-9/10 I/m afraid we're stuck at 10.
Scopes: Refs: Orion ST80, SV 80EDA f7, TS 102ED f11 Newts: AWB 130mm, f5, Z12 f5; Cats: VMC110L, Intes MK66,VMC200L f9.75 EPs: KK Fujiyama Orthoscopics, 2x Vixen NPLs (40-6mm) and BCOs, Baader Mark IV zooms, TV Panoptics, Delos, Plossl 32-8mm. Mixed brand Masuyama/Astroplans Binoculars: Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker IV, Vixen Porta II, Celestron CG5
User avatar
Michael131313 Mexico
Orion Spur Ambassador
Articles: 0
Offline
Posts: 966
Joined: Sun May 12, 2019 5:39 pm
4
Location: San Jose del Valle , Nayarit, Mexico
Status:
Offline

Re: a MOND theory that is not falsified by the CMB?

#4

Post by Michael131313 »


Thanks for the update nFA.
ES AR 102 102mm, f/6.5, ES 254mm f/5 DOB, Obie 10x50, GSO SV 30mm, ES 68° 20mm, ES 82° 14mm, 11mm, 8.8 mm, 6.8mm, 4.7mm. Twilight 1 mount.
Post Reply

Create an account or sign in to join the discussion

You need to be a member in order to post a reply

Create an account

Not a member? register to join our community
Members can start their own topics & subscribe to topics
It’s free and only takes a minute

Register

Sign in

Return to “Astrophysics”