What would it take to falsify the "big bang" model of cosmology?

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Catastrophe

"There never was a good war, or a bad peace."
As a follow-up to my post #121, I would be most grateful if anyone can throw any light on this item.

P.S. Neither can I see any backward extrapolation of an expansion to a single point as being in any way justified - even more so, when the expansion itself is not smooth, and the more so when punctuated by an expansion of spacetime at greater than light speed. Why not an expansion back to a non-infinitesimal nexus?
If Hubble's "law" is to hold, it is my understanding (?????) that if galaxies, having mass, they cannot travel > c, then, to get around this, if I understand correctly, a 'fudge' is introduced stating, that not the galaxies, but spacetime is that which is expanding faster than light?????.

OoooooooooPs! Does not Hubble's "law" state that it is the galaxies which are moving away from each other????

Cat :)
 
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Catastrophe

"There never was a good war, or a bad peace."
(Contd.) For your information:
Hubble's law - Wikipedia
https://en.wikipedia.org › wiki › Hubble's_law


"Hubble's law, also known as the Hubble–Lemaître law, is the observation in physical cosmology that galaxies are moving away from Earth at speeds ... " et cetera
Interpretation · ‎Derivation of the Hubble... · ‎Units derived from the Hubble...

Where is my error, please?

Does BBT require that more distant galaxies are receding faster than light, or should Hubble's Law be corrected to state that some non-material markers in spacetime suggest that spacetime itself is expanding faster than light?

Another question: When BBT uses a backward extrapolation towards a "singularity" (which I propose to be inadmissible) what happened at the point (first point, any point, whatever) ;)where/when c was reached in the first place?

Cat :)
 
And, finally, (I am posting these separate issues on 3 separate posts),

Is redshift due to receding galaxies or to receding or expanding spacetime? . . .

Cat :)
Yes. Doppler shift is what is used for the radial movement through space. Cosmological redshift describes the radial movement of space (expansion). At great distances, the Doppler motion (peculiar motion) becomes insignificant compared to the expansion rate.
 
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Catastrophe

"There never was a good war, or a bad peace."
Helio, thank you for your reply. I still don't get the point about Hubble's Law.
I thought recession (speed) was meant to be constant (H) x distance. However, if this continues to apply, recession (speed) will/has reach/reached c. Unless galaxies are non-material, this results in galaxies exceeding c. From your reply
Doppler shift is what is used for the radial movement through space.
I assume you are meaning physical movement of galaxies through spacetime, no? Also, if spacetime is expanding FTL, it cannot carry material (galaxies) with it or recession speed would become constant (at the limit) and Hubs would give all galaxies stopping dead. Constant(V) = H x Constant(D).

If, at some point, you are suggesting Hubs no longer applies, what replaces it. Can spacetime, containing no physical mass and/or light not originating from a physical object (viz. galaxy) produce a Doppler Effect?

Cat :)
 
Helio, thank you for your reply. I still don't get the point about Hubble's Law.
I thought recession (speed) was meant to be constant (H) x distance. However, if this continues to apply, recession (speed) will/has reach/reached c. Unless galaxies are non-material, this results in galaxies exceeding c. From your reply I assume you are meaning physical movement of galaxies through spacetime, no? Also, if spacetime is expanding FTL, it cannot carry material (galaxies) with it or recession speed would become constant (at the limit) and Hubs would give all galaxies stopping dead. Constant(V) = H x Constant(D).
The FTL speed of a galaxy being carried away by space, is the speed relative to us. It could be treated as not moving at all, arguing we are the galaxy traveling FTL (relative to it).

The ballon analogy helps understand this nuance. Put a number of dots on a small balloon, then while inflating the ballon, pick any dot and look at the speed of the dot nearest to it, then note the speed of a dot farther away from your dot. The farther the dot, the faster the relative speed to your “fixed” dot. That rate is the basis for the H-L constant.

On a much larger scale, at some point, a very distant ballon dot will be moving FTL. But, light from this FTL region on your huge ballon will soon propagate to a closer region that isn’t FTL, relative to your dot. Thus it will eventually reach your reference dot.

Traditional Doppler equations can’t handle FTL redshifts, hence we have the cosmological redshift equations.
 
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Aug 14, 2020
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Infinity is impossible to observe and thus is dismissed out of hand by astronomers and physicists for the Universe. It is possible for an infinity of universes to exist, to have always existed, but that infinity will never be observed, or detected, from anywhere local in it. So, what exactly are we left with observing and detecting? Infinity closed up to and zeroed out (as infinity) at distant finite horizons of existence and only potentials of it left over.
 

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