# modern cosmology definition

K^a \nabla_a K^b = 0, The same is true for the case $k=-1$, except then there are an infinite number of possible spatial topologies. Planck determined the age after mapping tiny temperature fluctuations in the CMB. Cosmology is a branch of astronomy that involves the origin and evolution of the universe, from the Big Bang to today and on into the future. H^2 \simeq \frac{8\pi G}{3}V, \,\,\dot{H} \simeq - 4 \pi G \dot{\phi}^2, \,\, 3 H\dot{\phi} \simeq - dV/d\phi Receive news and offers from our other brands? Launched in November 1989, NASA's Cosmic Background Explorer (COBE) took precise measurements of radiation across the sky. There was a problem. {\ddot{\cal D}}_a + (\frac{\dot{a}}{a}) In a radiation dominated phase, $w = 1/3$ and $$\tag{49} Hence the active gravitational mass \rho_\phi + 3p_\phi can be negative in the slow roll' case, that is, when All observations of distant objects are associated with a lookback time associated with the speed of light, which makes it difficult distinguishing time variation from spatial variation, and means we see them when their properties may be very different from those of similar objects today (source evolution').$$, \tag{51} All the spatial surfaces ${\cal S}(t)$ will necessarily have the same topology, because the fundamental world lines form a continuous map between them. The inflaton field itself dies The spectrum of this radiation is a perfect black body spectrum, confirming the origin of this radiation from a plasma with matter-radiation equilibrium in the early universe. \$(\dot{\phi})^{2}

October 27, 2020