this post was submitted on 13 Aug 2024
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[–] [email protected] 6 points 4 months ago (1 children)

Well, following the main reference in the Wikipedia page leads to this:

The implied velocity for the Solar System barycenter is v = 369.82 ± 0.11 km s−1, assuming a value T0 = Tγ , towards (l, b) = (264.021◦ ± 0.011◦, 48.253◦ ± 0.005◦) [13]. Such a Solar System motion implies a velocity for the Galaxy and the Local Group of galaxies relative to the CMB. The derived value is vLG = 620 ± 15 km s−1 towards (l, b) = (271.9◦ ± 2.0◦, 29.6◦ ± 1.4◦) [13], where most of the error comes from uncertainty in the velocity of the Solar System relative to the Local Group. The dipole is a frame-dependent quantity, and one can thus determine the ‘CMB frame’ (in some sense this is a special frame) as that in which the CMB dipole would be zero. Any velocity of the receiver relative to the Earth and the Earth around the Sun is removed for the purposes of CMB anisotropy studies, while our velocity relative to the Local Group of galaxies and the Local Group’s motion relative to the CMB frame are normally removed for cosmological studies. The dipole is now routinely used as a primary calibrator for mapping experiments, either via the time- varying orbital motion of the Earth, or through the cosmological dipole measured by satellite experiments.

Do any references suggest this dipole is under debate?

[–] [email protected] 2 points 4 months ago* (last edited 4 months ago) (1 children)

Here is a paper from University College London LINK

And researcher Saadeh's following interview LINK

Which supports the idea that, based on observed CMB data compared to mathematical models, the universe behaves the same in every direction, an anisotropic model with no preferred motion direction.

[–] [email protected] 2 points 4 months ago (1 children)

Ok, I guess the idea that the CMB suggests movement relative to a quasi-absolute reference frame really has become disputed lately... I also found this newer paper by the same authors. It's a pity, I liked the idea.

[–] [email protected] 1 points 4 months ago* (last edited 4 months ago)

Same, it gave credence to the concept of a potential center of the big bang being something we could find and observe, which is just really cool to think about.