Physics
Cosmology
The Inflationary Universe Standard Model Cosmic Inflation Cosmological Constant Cosmic Microwave Background
Read →The Inflationary Universe
source The Inflationary Universe: A Possible Solution To The Horizon And Flatness Problems (Guth, 1980) Questions I still have DONE WHY#1: why is that …
Read →Standard Model (Cosmology)
This refers to the Cosmological “Standard Model”, i.e. the CDM. This is not the same as the Standard Model of Particle Physics Lambda-CDM …
Read →Cosmological Principle
The Cosmological Principle states that at large enough scales (>100Mpc) the universe’s matter distribution is isotropic and homogeneous and should not …
Read →Cosmological Constant
TODO
Read →Cosmic Microwave Background
TODO
Read →Manifold
A manifold is a topological space that locally resembles Euclidean space near each point. As defined in Physics An N-dimensional manifold of points is one for …
Read →Shape of the Universe
Open/Closed/Flat TODO
Read →Principle of Relativity
The Principle of Relativity states that: The laws of physics take the same form in every intertial frame. No exception has been found to this principle, and it …
Read →Olber's Paradox
The Problem People used to believe that the Universe was infinite (in age and size) and static. If this were true Why is the night sky not as bright as day? …
Read →Newtons Laws of Motion
I In an intertial frame of reference (i.e. a frame of reference undergoing zero acceleration), an object at rest stays at rest (or, similarly, keeps its initial …
Read →Newtonian Spacetime
Newtonian Spacetime differs from Relativistic spacetime in that time is considered an absolute (i.e. ). Transformations between reference …
Read →Mechanics
Read →Isotropy (Physics)
Isotropy means that direction is not preferred, and that there is uniformity in any orientation. Specifically, in Astrophysics and Cosmology, it means that …
Read →Inertial Frames
Above are two frames in Cartesian coordinates, and . We have coordinates , which define our dimensions. Inertial Frame An …
Read →Homogeneous (Physics)
Homogeneous means that location is not preferred, that the physics are the same at any point. Specifically, in Astrophysics and Cosmology, it means that there …
Read →Generalized Coordinates
Generalized coordinates are useful when calculating Lagrangians or Hamiltonians. The term itself, refers to the parameters that describe the configuration of a …
Read →General Relativity
Concepts Inertial Frames Newtons Laws of Motion
Read →Galilean Transformations
In Newton’s formulation of spacetime, time is an absolute; meaning that every observer experiences the same flow of time. Assuming an inertial frame with …
Read →Flatness Problem
Overview In the Big Bang model there are multiple parameters which appear to be “fine tuned” in that, small changes to a given parameter have …
Read →Equations of Motion
Linear Motion (under constant ) \begin{equation} \mathbf{r} …
Read →Degenerate Coordinate Systems
Any coordinate system which cannot describe an entirety of a space As an example, polar coordinates are degenerate at
Read →Curvature
TODO
Read →Cosmic Inflation
Inflation Inflation (Cosmic) is a theory put forth (originally, by Alan Guth in his 1980 paper) to explain why, if the universe is full of mass, is it not …
Read →Configuration Space
The vector space defined by generalized coordinates. Example: The position of a particle in Euclidean 3-space is defined by the generalized coordinate \(q = (x, …
Read →Black Holes as Primordial Dark Matter
source: Physicists Argue That Black Holes From the Big Bang Could Be the Dark Matter Primordial Black Holes A “Primordial Black Hole” (PBH), is a …
Read →Black Hole Information Paradox
High-level The result of the marrying of QM with GR. (Initially, Hawking’s) calculations suggested that information would permanently disappear in a black …
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