# Tag Info

1

The energy density of the Cosmic Microwave Background (CMB) is $4.19 \times 10^{-14} J/m^3$. This value can be calculated from the CMB temperature being 2.728 K and $energy$ $density = aT^4$ where $a$ is the Radiation Constant. You can multiply the energy density by your volume of interest such as that of the observable universe if you want total energy. ...

0

If you knew the maximum entropy $S_{\text{max}}$ possible for a system then you know how many possible states there are because $$S_{\text{max}}=\sup_{p_n}\left\{-\sum_nkp_n\log p_n\right\}=k\log N,$$ where $k$ is Bolzmann's constant, and $N$ is the number of states. There is a limit to the amount of entropy a volume of space can hold, and such a maximally ...

0

This is similar to the idea that if the universe was infinite in size and infinitely old, the sky would be as bright as the sun, since every point in the sky would end on a star, somewhere in the infinite universe. Since this is not the case, it led people to conclude that the universe is either finite in size or age. Similarly, even if the universe was ...

0

One cannot simply observe edge of universe without taking in consideration of the big bang being a silent inflation rather than a large explosive inflation. As when universe was created the temperature was too hot for matter to exist thus the photons being pure energy rather than a bright explosion. Next, if the big bang happened in presence of matter ...

2

You are thinking that the big bang happened in a particular point in space and then expanded outwards from that point. This is not true. The big bang happened at all points in space. This is because space itself expanded in the actual bang. Therefore each point in space has its own "horizon" of 13.7 billion light years across. This edge is due to light ...

Top 50 recent answers are included