2025 · Proceedings of the National Academy of Sciences
Could dark energy be changing over time?
Verdict
UNSCIENTIFIC
Neither the paradigm nor the study inside it passes. The verdict is unscientific.
1·Study methodology · inside the paradigm
UNSCIENTIFIC
Does not follow the scientific method within Cosmology / Dark Energy Model.
2·Paradigm · Cosmology / Dark Energy Model
UNSCIENTIFIC
Fails the tests. The worse layer decides.
How the verdict is decided
The verdict grades both layers: the paradigm this study assumes, and how the study was carried out inside it. Both must be scientific for the whole thing to be scientific. A clean method inside an unscientific paradigm is unscientific. An unscientific method inside a better paradigm is unscientific. A split on either layer is mixed. The worse layer decides.
1·Study methodology
Did this study test its claim with methods that are independent, falsifiable, and non-circular?
UNSCIENTIFIC
This paper claims that DESI's observations suggest what the model calls dark energy has varied in strength over cosmic time, weakening in the current era. All three tests fail.
Independently Verifiable
Fail
The spectrometers produce spectral lines and redshift measurements, and the cosmological model tells you those lines mean space expanded and dark energy exists.
Falsifiable
Fail
A null result would be called systematic errors or dataset selection, not accepted as disproof.
Non-Circular
Fail
DESI was built to study dark energy, and the BAO ruler and redshift-as-expansion reading both come from the cosmological model the instrument claims to test.
Why
DESI captures light from distant galaxies and quasars. Spectrometers measure where spectral lines fall, and the cosmological model reads those shifted lines as evidence that space expanded. The BAO concept used as a standard ruler for distance comes from big bang theory. The redshift-as-expansion reading comes from the same framework. They combine these distances with redshifts to plot the universe's expansion history, then read patterns in that history as dark energy changing over time. Every link assumes the cosmological model. The instrument was built to study dark energy. The standard ruler was defined by big bang physics. A stranger who rejects cosmology sees spectral lines and object positions, not dark energy. If the data showed constant dark energy, the field would call it systematic errors or insufficient data. The paper itself shows the result shifts between 2.8 and 4.2 sigma depending on which datasets are included.
2·Paradigm · Cosmology / Dark Energy Model
Does the framework this study assumes pass the three tests?
UNSCIENTIFIC
Independently Verifiable
Fail
Dark energy has never been observed without the cosmological model that invented it.
Falsifiable
Fail
No observation can kill the framework because any unexpected result gets a new theoretical patch.
Non-Circular
Fail
The instruments and interpretive frameworks were built from the cosmological model they claim to test.
Why
The dark energy paradigm was invented to explain why distant supernovae appeared dimmer than expected in the 1990s. The model named an unknown antigravitational force, built instruments to study it, and now reports patterns in instrument output as evidence about the force's properties. Dark energy has never been observed without the model that created it. Nobody has seen it. The entity exists only as the model's interpretation of redshift and distance data. The paradigm cannot die. If dark energy is constant, the cosmological constant survives. If it varies, quintessence or interacting dark sector models get proposed. If results are ambiguous, the field calls for more data. Every unexpected result gets a new theoretical patch. The null energy condition violation and negative neutrino mass problems are debated rather than treated as disproof. The instruments were built from the model's assumptions. The BAO standard ruler comes from big bang theory. The tool was built to find what the model already named.
From the paper
This implied that some unknown effect was acting in opposition to gravity, causing the expansion of space to accelerate. This unknown thing was named “dark energy.”
Measuring that redshift allows DESI scientists to determine how much the universe has expanded since light left the galaxy or quasar of interest.
BAOs thus provide a standard ruler in the universe.
Depending on which supernova dataset is included, the results can also be a more humdrum 2.8 sigma.