I propose a formula for the dark energy density (dark energy formula): ΩΛ = ΩbAeh/t2 In this equation: ΩΛ is the dark energy density, with the estimated value from 0.712 to 0.743, according to WMAP seven-year data release ; Ωb is the baryon density, 0.0456 ±0.0016, according to WMAP seven-year data release ; Aeh is the area of a sphere represented by the event horizon of the Universe, calculated as 4πr2, where r is the distance to the event horizon (currently estimated at about 16 billion light years ); t is the age of the Universe, currently 13.75 ±0.11 billion years, according to WMAP seven-year data release . This formula adequately describes the state of the Universe, as the calculated value of the dark energy density is in conformity with its actual value within the established margins (from 0.712 to 0.743): for the minimum calculated value, ΩΛ = 0.044×4π×162/13.862 = 0.737 for the maximum calculated value, ΩΛ = 0.0472×4π×162/13.642 = 0.816 References  Table 8 on p. 39 of Jarosik, N., et.al. (WMAP Collaboration). Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Sky Maps, Systematic Errors, and Basic Results (PDF). nasa.gov (2010). (http://lambda.gsfc.nasa.gov/product...year/basic_results/wmap_7yr_basic_results.pdf, retrieved 2011-10-18).  Tamara M. Davis, Charles H. Lineweaver. Misconceptions about the Big Bang, Scientific American (2005), and Expanding Confusion: Common Misconceptions of Cosmological Horizons and the Superluminal Expansion of the Universe, Publications of the Astronomical Society of Australia, 2004, 21, 97-109.