Astronomy & Space Science · AST-765
The Cosmological Constant: Advanced Connections
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Overview
Advanced view of The Cosmological Constant
The cosmological constant, written Λ, is the simplest dark-energy term in Einstein's equations. It behaves like an energy density intrinsic to empty space that remains constant as the universe expands and has equation-of-state parameter w = -1.
The cosmological constant provides the baseline model for expansion forecasts, cosmic distances, structure growth, and tests for evolving dark energy.
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References & evidence
Source library for this chapter
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- 01DESI DR2 Results GuideOpen source ↗
DESI Collaboration
- 02The Big Bang — SummaryOpen source ↗
OpenStax Astronomy 2e · Mar 9, 2022
View claim-by-claim traceability3 verified claims
A constant vacuum-like energy density has negative pressure in general relativity.
supported · checked Sep 22, 2026A constant-Λ model fits a wide combination of CMB, supernova, BAO, and large-scale-structure data remarkably well.
supported · checked Sep 22, 2026The cosmological constant, written Λ, is the simplest dark-energy term in Einstein's equations.
supported · checked Sep 22, 2026