# Dark energy explained by an inadequate fitting of the FLRW metric

## TL;DR

This paper suggests that the apparent accelerated expansion of the universe and the need for dark energy could be artifacts of biased measurements and inadequate fitting of the FLRW metric, especially due to non-random distribution of supernovae.

## Contribution

It demonstrates that measurement biases and fitting procedures can lead to an apparent cosmological constant, challenging the necessity of dark energy in explaining cosmic acceleration.

## Key findings

- Bias in supernova measurements can mimic dark energy effects.
- Inadequate FLRW fitting due to matter distribution bias explains accelerated expansion.
- The apparent cosmological constant may be an artifact of measurement and fitting biases.

## Abstract

Approximating a real manifold by an idealized one requires to calibrate the parameters characterizing the idealized manifold in function of the real one. This calibration is a purely conventional process and can generally be done in several ways, leading to different fittings. In practice, however, all possible fittings cannot be considered as representative of the real manifold. Approximating the real metric of the universe by the FLRW metric would be adequate only if both corresponding structures, defined by the space-time interval, are equivalent on large scales. This requirement puts some constraints on what would be a representative FLRW metric. We show that the way how measurements on SNIa are interpreted to determine the evolution of the scale factor implicitly define the calibration process, and that this one is compatible with the aforementioned constraints. On a theoretical point of view, this indicates that the as fitted FLRW metric would indeed be representative of the real one. On a practical point of view, however, we show that a bias in the measurements could invalidate this conclusion. The bias comes from the fact that SNIa are not randomly distributed over space, but are probably mostly located in regions were matter is largely present, i.e., in overdense regions. We explain how this bias could account for the apparent accelerated expansion of the universe, without needing to introduce the dark energy assumption. We show in particular that this bias leads to an inadequate fitting of the FLRW metric, resulting in the appearance of a new term in the evolution equation of the related scale factor, being equivalent to the cosmological constant.