This is what DESI aims to do: make precise measurements of the obvious size of these bubbles, whether near or far, by determining the distance between galaxies and quasars over 11 billion years. This data can then be cut into pieces to determine how fast the universe has expanded at every point in time in the past, simulating how dark energy affects that expansion the more it is.
Upward trend
Last year’s results are based on an analysis of full-year data obtained from cosmic times in seven different slices, including the largest 450,000 quasars collected ever, with a record accuracy of 0.82% in the most distant period (8 to 11 billion years ago). Despite basic consistency with the Lamba CDM model, some subtle differences emerge when these first-year results are combined with data from other studies, involving cosmic microwave background radiation and IA Supernovae type.
Essentially, these differences suggest that dark energy may become weaker and weaker. In terms of confidence, the results were combined with the CMB dataset using the 2.6-sigma level of the DESI data. When supernova data is added, these numbers grow to 2.5-sigma, 3.5-Sigma or 3.9-Sigma levels, depending on which specific Supernova dataset is used.
A DESI co-spokesman will say in the University of Waterloo’s percival that it is important to combine DESI data with other independent measurements. “All different experiments should give us the same answers to how important we are to the universe, which expands rapidly. For the basic properties of this model.”
These latest results cover the first three years of data collected, covering nearly 15 million galaxies and quasars. Again, only the DESI data is consistent with the lambda CDM, i.e., the dark energy is constant. Once again, when combined with other datasets (from CMB, supernova and weak gravity lens studies), it is implied that dark energy may change over time. The confidence level ranges from 2.8 to 4.2 Sigma, depending on the combination of the dataset, which is just less than five Sigma thresholds.
This may make ordinary citizens progressive, but the reality is more complex. “DESI data itself is not progressive,” Percival said. “We now have three years of data, not one year of data. It’s important, not only because of the area, but because we add overlap. The way we do our survey is that we have built plates on the sky, and after three years instead of a year of operations, our data is more complete, so our data is more complete, so that our data is more complete, and that makes more and more, this is complete, and that’s so complete that the full content is complete. The measurement itself is much better.
