Search
- https://phys.libretexts.org/Courses/University_of_California_Davis/Physics_156%3A_A_Cosmology_Workbook/01%3A_Workbook/1.10%3A_The_Friedmann_EquationSticking with our Newtonian expanding universe, we will now derive the Friedmann equation that relates how the scale factor changes in time to the mass/energy density. We will proceed by using the Ne...Sticking with our Newtonian expanding universe, we will now derive the Friedmann equation that relates how the scale factor changes in time to the mass/energy density. We will proceed by using the Newtonian concept of energy conservation. (You may be surprised to hear me call this a Newtonian concept, but the fact is that energy conservation does not fully survive the transition from Newton to Einstein).
- https://phys.libretexts.org/Courses/Chicago_State_University/PH_S_1150%3A_Basic_Astronomy/17%3A_Dark_Energy_and_the_Fate_of_the_Universe/17.03%3A_The_Friedmann_Equation_and_the_Fate_of_the_UniverseIn this equation, H is the Hubble parameter (expansion rate), ρ is the average density of matter and energy in the Universe, S is the scale factor, and k is a number that describes the overall curvatu...In this equation, H is the Hubble parameter (expansion rate), ρ is the average density of matter and energy in the Universe, S is the scale factor, and k is a number that describes the overall curvature of the Universe. The age of the Universe will be the amount of time that passes between the beginning of the Universe and the point at which the scale factor again becomes zero (blue line intersects the x-axis).
- https://phys.libretexts.org/Bookshelves/Modern_Physics/Book%3A_Spiral_Modern_Physics_(D'Alessandris)/8%3A_Misc_-_Semiconductors_and_Cosmology/8.2%3A_Modeling_the_Universe_(Project)Cosmology is the scientific study, and the associated mathematical models, of the universe as a whole. Amazingly, using only a few basic scientific principles one can construct a quantitative model of...Cosmology is the scientific study, and the associated mathematical models, of the universe as a whole. Amazingly, using only a few basic scientific principles one can construct a quantitative model of the universe that agrees surprisingly well with observational data. This model not only is in agreement with current observations, but makes clear predictions for the age of the universe and its future fate.
- https://phys.libretexts.org/Courses/Skidmore_College/Introduction_to_General_Relativity/07%3A_Cosmology/7.05%3A_The_Friedmann_EquationIn 1922, Alexander Friedmann combined the Friedmann–Lemaître–Robertson–Walker metric with the Einstein Field equations and discovered a way to determine a(t). We now call it the Friedmann Equation.
- https://phys.libretexts.org/Bookshelves/Astronomy__Cosmology/Big_Ideas_in_Cosmology_(Coble_et_al.)/17%3A_Dark_Energy_and_the_Fate_of_the_Universe/17.03%3A_The_Friedmann_Equation_and_the_Fate_of_the_UniverseIn this equation, H is the Hubble parameter (expansion rate), ρ is the average density of matter and energy in the Universe, S is the scale factor, and k is a number that describes the overall curvatu...In this equation, H is the Hubble parameter (expansion rate), ρ is the average density of matter and energy in the Universe, S is the scale factor, and k is a number that describes the overall curvature of the Universe. The age of the Universe will be the amount of time that passes between the beginning of the Universe and the point at which the scale factor again becomes zero (blue line intersects the x-axis).
