Related Experiment Video
Updated: May 27, 2026
13:02
Three-dimensional Particle Tracking Velocimetry for Turbulence Applications: Case of a Jet Flow
Published on: February 27, 2016
Cosmic curvature from de Sitter equilibrium cosmology
1Department of Astronomy and Astrophysics and Kavli Institute for Cosmological Physics, The University of Chicago, 5640 South Ellis Avenue, Chicago, Illinois 60637, USA.
Physical Review Letters
|November 24, 2011
Summary
De Sitter equilibrium cosmology predicts detectable universe curvature today. This curvature depends on matter-to-cosmological-constant density and initial bubble curvature, offering insights into the early universe.
Area of Science:
- Cosmology
- Theoretical Physics
- Astroparticle Physics
Background:
- The standard cosmological model assumes a spatially flat universe.
- De Sitter spacetime describes a universe with a positive cosmological constant, often associated with cosmic inflation.
Purpose of the Study:
- To investigate the predictions of de Sitter equilibrium cosmology regarding the observable curvature of the universe.
- To identify key parameters that determine the predicted curvature.
Main Methods:
- Theoretical analysis of de Sitter equilibrium cosmology.
- Derivation of the relationship between predicted curvature and cosmological parameters.
Main Results:
- De Sitter equilibrium cosmology generically predicts observable levels of universe curvature.
- The predicted curvature, Ω(k), is determined by the ratio of nonrelativistic matter density to cosmological constant density (ρ(m)(0)/ρ(Λ)) and the initial bubble curvature Ω(k)(B).
- The prediction is independent of inflation scale and potential shape.
Conclusions:
- Future measurements of ρ(m)(0)/ρ(Λ) and Ω(k) can test de Sitter equilibrium cosmology.
- This framework offers a new avenue to probe the very early universe and potentially falsify or support specific cosmological models.
Related Concept Videos
01:17Space-Time Curvature and the General Theory of Relativity
In 1905, Albert Einstein published his special theory of relativity. According to this theory, no matter in the universe can attain a speed greater than the speed of light in a vacuum, which thus serves as the speed limit of the universe.
This has been verified in many experiments. However, space and time are no longer absolute. Two observers moving relative to one another do not agree on the length of objects or the passage of time. The mechanics of objects based on Newton's laws of motion,...
This has been verified in many experiments. However, space and time are no longer absolute. Two observers moving relative to one another do not agree on the length of objects or the passage of time. The mechanics of objects based on Newton's laws of motion,...
01:26Gauss's Law: Spherical Symmetry
A charge distribution has spherical symmetry if the density of charge depends only on the distance from a point in space and not on the direction. In other words, if the system is rotated, it doesn't look different. For instance, if a sphere of radius R is uniformly charged with charge density ρ0, then the distribution has spherical symmetry. On the other hand, if a sphere of radius R is charged so that the top half of the sphere has a uniform charge density ρ1 and the bottom half has a uniform...
01:14Bending of Curved Members - Strain Analysis
The mechanics of deformation in curved members, such as beams or arches, under bending moments, involve complex responses. When such a member, symmetric about the y-axis and shaped like a segment of a circle centered at point C, is subjected to equal and opposite forces, its curvature and surface lengths change significantly. This alteration results in the shift of the curvature's center from C to C', indicating a tighter curve.
The important part of bending analysis for such a member is the...
The important part of bending analysis for such a member is the...
01:18Deformations in a Symmetric Member in Bending
When analyzing the deformation of a symmetric prismatic member subjected to bending by equal and opposite couples, it becomes clear that as the member bends, the originally straight lines on its wider faces curve into circular arcs, with a constant radius centered at a point known as Point C. This phenomenon helps to understand the stress and strain distribution within the member more clearly.
When the member is segmented into tiny cubic elements, it is observed that the primary stress...
When the member is segmented into tiny cubic elements, it is observed that the primary stress...
01:21Schwarzschild Radius and Event Horizon
No object with a finite mass can travel faster than the speed of light in a vacuum. This fact has an interesting consequence in the domain of extremely high gravitational fields.
The minimum speed required to launch a projectile from the surface of an object to which it is gravitationally bound so that it eventually escapes the object’s gravitational field is called the escape velocity. The escape velocity is independent of the mass of the object. Merging the idea of escape velocity with the...
The minimum speed required to launch a projectile from the surface of an object to which it is gravitationally bound so that it eventually escapes the object’s gravitational field is called the escape velocity. The escape velocity is independent of the mass of the object. Merging the idea of escape velocity with the...
01:21Deformations in a Transverse Cross Section
When a material is subjected to uniaxial stress, it elongates or contracts in the direction of the applied force, and also undergoes changes in the perpendicular directions. This behavior is crucial for understanding how materials behave under stress and is governed by mechanical properties such as Poisson's ratio v, which measures the ratio of transverse strain to axial strain.
As the material stretches, it expands or contracts in orthogonal directions to the load. This phenomenon varies...
As the material stretches, it expands or contracts in orthogonal directions to the load. This phenomenon varies...