Equation 4 · Part 6 · Comparing the Main Approaches to Precision Cosmology
addition
addition
What this part means
Add the term after the plus sign to the term or group before it.
Its job in the formula
Add the term after the plus sign to the term or group before it.
Full expression→addition→Article meaning
The passage around this formula
Evolving dark energy , in the w0-wa parametrization, keeps the sound horizon alone and instead lets dark energy’s equation of state change with cosmic time: . where a is the cosmic scale factor (a = 1 today) and w = -1 recovers a plain cosmological constant. This is the family DESI’s DR2 BAO release put back on the table: fit jointly to DESI BAO, Planck CMB, and supernovae, a w0-wa model is preferred over flat LambdaCDM at up to several sigma, with the preferred trajectory suggesting dark energy was somewhat more negative than -1 in the past and is evolving toward less negative values now [ 3 , 4 ] .
Learn the underlying idea
Addition combines quantities; subtraction measures the signed difference between them. Parentheses show what is combined before the rest of the expression is evaluated.
Open the illustrated addition and subtraction in an equation guide →
Sources cited in the article section
- [5] Early Dark Energy Can Resolve The Hubble Tension ↗
- [6] The Ups and Downs of Early Dark Energy solutions to the Hubble tension: a review of models, hints and constraints circa 2023 ↗
- [4] Extended Dark Energy analysis using DESI DR2 BAO measurements ↗
- [3] DESI DR2 Results II: Measurements of Baryon Acoustic Oscillations and Cosmological Constraints ↗
These citations provide research context; check each source for the exact claim it supports.