Question

How can there be anything outside of the observable universe?

Answer 1

There are at least 2 trillion galaxies in the observable universe. Assuming the Universe is isotropic, the distance to the edge of the observable universe is roughly the same in every direction.

Density (of total energy): 9.9×10−27 kg/m3 ...

Volume: 4×1080 m3

Contents: Ordinary (baryonic) matter (4.9%); D...

Mass (ordinary matter): 4.5 x 10 51 kg.