The Mystery of the Expanding Universe Explained

Added: 2026-05-16

[00:00:00]Space is getting bigger right now. When astronomers look at distant galaxies, they see their light stretch to the red side of the spectrum, a real effect called redshift.

[00:00:10]That stretch means the space between us and those galaxies has grown while the light was traveling. Here is the key idea. Galaxies are not flying through space like bullets. Instead, space itself is expanding and carrying them apart.

[00:00:26]This comes from Einstein's general relativity, where space and time can stretch, curve, and evolve as the universe changes. The farther a galaxy is, the faster it seems to recede, which is what we call Hubble's law.

[00:00:39]So, when you look at the night sky, do you feel strange knowing that even the darkness between the stars is slowly growing? [music]