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  2. Cosmological constant - Wikipedia

    en.wikipedia.org/wiki/Cosmological_constant

    Using the values known in 2018 and Planck units for Ω Λ = 0.6889 ± 0.0056 and the Hubble constant H 0 = 67.66 ± 0.42 (km/s)/Mpc = (2.192 7664 ± 0.0136) × 10 −18 s −1, Λ has the value of = = = where is the Planck length. A positive vacuum energy density resulting from a cosmological constant implies a negative pressure, and vice versa.

  3. Exact trigonometric values - Wikipedia

    en.wikipedia.org/wiki/Exact_trigonometric_values

    In mathematics, the values of the trigonometric functions can be expressed approximately, as in ⁡ (/), or exactly, as in ⁡ (/) = /.While trigonometric tables contain many approximate values, the exact values for certain angles can be expressed by a combination of arithmetic operations and square roots.

  4. Equation of state (cosmology) - Wikipedia

    en.wikipedia.org/wiki/Equation_of_state_(cosmology)

    These problems are solved by cosmic inflation which has . Measuring the equation of state of dark energy is one of the largest efforts of observational cosmology . By accurately measuring w {\displaystyle w} , it is hoped that the cosmological constant could be distinguished from quintessence which has w ≠ − 1 {\displaystyle w\neq -1} .

  5. Friedmann equations - Wikipedia

    en.wikipedia.org/wiki/Friedmann_equations

    The first Friedmann equation is often seen in terms of the present values of the density parameters, that is [6] =, +, +, +,. Here Ω 0,R is the radiation density today (when a = 1 ), Ω 0,M is the matter ( dark plus baryonic ) density today, Ω 0, k = 1 − Ω 0 is the "spatial curvature density" today, and Ω 0,Λ is the cosmological constant ...

  6. List of trigonometric identities - Wikipedia

    en.wikipedia.org/wiki/List_of_trigonometric...

    A formula for computing the trigonometric identities for the one-third angle exists, but it requires finding the zeroes of the cubic equation 4x 3 − 3x + d = 0, where is the value of the cosine function at the one-third angle and d is the known value of the cosine function at the full angle.

  7. Cosmological constant problem - Wikipedia

    en.wikipedia.org/wiki/Cosmological_constant_problem

    In cosmology, the cosmological constant problem or vacuum catastrophe is the substantial disagreement between the observed values of vacuum energy density (the small value of the cosmological constant) and the much larger theoretical value of zero-point energy suggested by quantum field theory.

  8. Lambda-CDM model - Wikipedia

    en.wikipedia.org/wiki/Lambda-CDM_model

    The values of these six parameters are mostly not predicted by theory (though, ideally, they may be related by a future "Theory of Everything"), except that most versions of cosmic inflation predict the scalar spectral index should be slightly smaller than 1, consistent with the estimated value 0.96. The parameter values, and uncertainties, are ...

  9. Trigonometric tables - Wikipedia

    en.wikipedia.org/wiki/Trigonometric_tables

    The values for a/b·2π can be found by applying de Moivre's identity for n = a to a b th root of unity, which is also a root of the polynomial x b - 1 in the complex plane. For example, the cosine and sine of 2π ⋅ 5/37 are the real and imaginary parts , respectively, of the 5th power of the 37th root of unity cos(2π/37) + sin(2π/37)i ...