Difference between revisions of "Homogeneous Universe"
From Universe in Problems
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= Homogeneous and isotropic Universe, Hubble’s law = | = Homogeneous and isotropic Universe, Hubble’s law = | ||
− | + | $\left(\dot a \over a \right)^2$ | |
<div id="02001"></div>'''Problem 1.''' A system with constant magnetic field is homogeneous but not isotropic, because the direction along the field and perpendicular to it are not equivalent. On the contrary, a spherically symmetric distribution of electric charges is by construction isotropic, but not, in general, homogeneous. | <div id="02001"></div>'''Problem 1.''' A system with constant magnetic field is homogeneous but not isotropic, because the direction along the field and perpendicular to it are not equivalent. On the contrary, a spherically symmetric distribution of electric charges is by construction isotropic, but not, in general, homogeneous. |
Revision as of 08:58, 19 March 2012
Homogeneous and isotropic Universe, Hubble’s law
$\left(\dot a \over a \right)^2$
Problem 1. A system with constant magnetic field is homogeneous but not isotropic, because the direction along the field and perpendicular to it are not equivalent. On the contrary, a spherically symmetric distribution of electric charges is by construction isotropic, but not, in general, homogeneous.