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Using the Planck units, and the value evaluated in 2025 for the Hubble constant H 0 = 76.5 ± 2.2 (km/s)/Mpc = (2.48 ± 0.07) × 10 −18 s −1 [18], 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. If the energy density is ...
This is a list of lists, grouped by type of astronomical object. Solar System ... List of largest cosmic structures; List of the most distant astronomical objects;
The speed of light in IAU is the defined value c 0 = 299 792 458 m/s of the SI units. In terms of this speed, the old definition of the astronomical unit of length had the accepted value: [ 3 ] 1 au = c 0 τ A = ( 149 597 870 700 ± 3 ) m, where τ A is the transit time of light across the astronomical unit.
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} .
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.
The value of the Hubble constant in (km/s)/Mpc, including measurement uncertainty, for recent surveys [52] The value of the Hubble constant, H 0, cannot be measured directly, but is derived from a combination of astronomical observations and model-dependent assumptions. Increasingly accurate observations and new models over many decades have ...
In the tables, z is the cosmological redshift, c the speed of light, and h the dimensionless Hubble parameter, which has a value of approximately 0.7 (the Hubble constant H 0 = h × 100 km s −1 Mpc −1). Mpc stands for megaparsec. The co-ordinates (right ascension and declination) and distance given refer to the approximate center of the region.
This is a list of the largest cosmic structures so far discovered. The unit of measurement used is the light-year (distance traveled by light in one Julian year; approximately 9.46 trillion kilometres). This list includes superclusters, galaxy filaments and large quasar groups (LQGs). The structures are listed based on their longest dimension.