Compare · The Dark Universe

TeVeS (Tensor-Vector-Scalar) vs Skordis-Złośnik Aether Scalar-Tensor

Modified Gravity / MOND· within family

	TeVeS (Tensor-Vector-Scalar) Frontier	Skordis-Złośnik Aether Scalar-Tensor Frontier
Proposed	2004	2021
Key figures	Jacob Bekenstein	Constantinos Skordis, Tom Złośnik
In one sentence	Bekenstein's 2004 TeVeS is a relativistic theory that reduces to MOND in weak fields and to general relativity in strong fields, by adding a scalar and a vector field to the metric. It was the first serious relativistic MOND, but GW170817 constraints have substantially limited it.	Skordis and Złośnik's 2021 relativistic MOND theory is constructed from the start so that tensor modes propagate at light speed. It reproduces MOND galaxy-scale phenomenology while passing GW170817 by design.
Predictions	How much background light a galaxy or cluster bends (gravitational lensing) should follow the TeVeS values set by the visible matter alone, not the larger ΛCDM values that assume a dark-matter halo; the cleanest test is the ratio of lensing mass to ordinary (baryonic) mass in colliding clusters The acoustic peaks in the cosmic microwave background, the regular ripples left by sound waves in the early universe, should come out with different heights and spacings than ΛCDM predicts, testable against Planck satellite data Tensor mode propagation speed potentially different from light speed (now tightly constrained by GW170817)	Galaxy dynamics reproduce MOND at low accelerations, including the radial acceleration relation Tensor mode propagation speed equals c exactly, by construction (no GW170817 conflict) The cosmic microwave background's acoustic peaks and the way galaxies cluster on large scales should show measurable deviations from ΛCDM; the exact numbers await fitting the theory to all the major datasets at once
Where it breaks	GW170817 constrains tensor mode propagation speed to match light speed to one part in 10^15; generic TeVeS configurations violate this and require fine-tuning to survive Cosmological perturbation analyses find TeVeS struggles to reproduce the CMB acoustic peaks and large-scale structure formation as well as ΛCDM The theory's field content (scalar plus vector plus free interpolating functions) is seen as baroque relative to ΛCDM's simplicity Active relativistic-MOND research has moved to newer frameworks (Skordis-Złośnik) that handle GW170817 from the start, leaving TeVeS as a reference rather than a live candidate	A full global fit to CMB plus BAO plus supernovae plus galaxy data has not been completed; the framework is too young to know if it can match all data simultaneously Like TeVeS, the theory adds extra fields and free functions; some critics see it as replacing [[dark matter]] with an equally elaborate modified-gravity sector The galaxy-scale success is real, but it is inherited from MOND-original, and so are MOND's unsolved problems: the theory still faces the cluster-scale mass gap (Bullet Cluster) and the CMB acoustic-peak fit, neither of which Skordis-Złośnik has yet shown it resolves Without a unique microscopic motivation for the specific field content, the theory is hard to falsify in a sharp sense
Key unresolved problem	The gravitational-wave speed problem: the 2017 GW170817 event showed gravity travels at the speed of light, yet most versions of TeVeS make gravitational waves travel at a different speed, so the theory survives only with heavy fine-tuning.	The untested-at-scale problem: no one has yet checked the Skordis-Złośnik theory against all the big cosmological datasets at once, the cosmic microwave background, galaxy surveys, supernovae, and sound-wave imprints (BAO), so we cannot tell if it explains everything ΛCDM does.
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TeVeS (Tensor-Vector-Scalar)

2004 · Frontier

Skordis-Złośnik Aether Scalar-Tensor

2021 · Frontier

Proposed

2004

2021

Key figures

Jacob Bekenstein

Constantinos Skordis, Tom Złośnik

In one sentence

Bekenstein's 2004 TeVeS is a relativistic theory that reduces to MOND in weak fields and to general relativity in strong fields, by adding a scalar and a vector field to the metric. It was the first serious relativistic MOND, but GW170817 constraints have substantially limited it.

Skordis and Złośnik's 2021 relativistic MOND theory is constructed from the start so that tensor modes propagate at light speed. It reproduces MOND galaxy-scale phenomenology while passing GW170817 by design.

Predictions

How much background light a galaxy or cluster bends (gravitational lensing) should follow the TeVeS values set by the visible matter alone, not the larger ΛCDM values that assume a dark-matter halo; the cleanest test is the ratio of lensing mass to ordinary (baryonic) mass in colliding clusters
The acoustic peaks in the cosmic microwave background, the regular ripples left by sound waves in the early universe, should come out with different heights and spacings than ΛCDM predicts, testable against Planck satellite data
Tensor mode propagation speed potentially different from light speed (now tightly constrained by GW170817)

Galaxy dynamics reproduce MOND at low accelerations, including the radial acceleration relation
Tensor mode propagation speed equals c exactly, by construction (no GW170817 conflict)
The cosmic microwave background's acoustic peaks and the way galaxies cluster on large scales should show measurable deviations from ΛCDM; the exact numbers await fitting the theory to all the major datasets at once

Where it breaks

GW170817 constrains tensor mode propagation speed to match light speed to one part in 10^15; generic TeVeS configurations violate this and require fine-tuning to survive
Cosmological perturbation analyses find TeVeS struggles to reproduce the CMB acoustic peaks and large-scale structure formation as well as ΛCDM
The theory's field content (scalar plus vector plus free interpolating functions) is seen as baroque relative to ΛCDM's simplicity
Active relativistic-MOND research has moved to newer frameworks (Skordis-Złośnik) that handle GW170817 from the start, leaving TeVeS as a reference rather than a live candidate

A full global fit to CMB plus BAO plus supernovae plus galaxy data has not been completed; the framework is too young to know if it can match all data simultaneously
Like TeVeS, the theory adds extra fields and free functions; some critics see it as replacing [[dark matter]] with an equally elaborate modified-gravity sector
The galaxy-scale success is real, but it is inherited from MOND-original, and so are MOND's unsolved problems: the theory still faces the cluster-scale mass gap (Bullet Cluster) and the CMB acoustic-peak fit, neither of which Skordis-Złośnik has yet shown it resolves
Without a unique microscopic motivation for the specific field content, the theory is hard to falsify in a sharp sense

Key unresolved problem

The gravitational-wave speed problem: the 2017 GW170817 event showed gravity travels at the speed of light, yet most versions of TeVeS make gravitational waves travel at a different speed, so the theory survives only with heavy fine-tuning.

The untested-at-scale problem: no one has yet checked the Skordis-Złośnik theory against all the big cosmological datasets at once, the cosmic microwave background, galaxy surveys, supernovae, and sound-wave imprints (BAO), so we cannot tell if it explains everything ΛCDM does.

Reader vote

No votes yet