Why is space so dark?

Space is dark because there is almost nothing there to scatter light toward your eyes. Sunlight and starlight travel through the vacuum, but unless that light hits dust, air, a planet, or you, the space between objects stays black.

Earth’s sky looks blue because our air redirects sunlight in every direction. On the moon, astronauts stood in sunshine on bright ground while the sky stayed black overhead, showing how much our glowing daytime sky depends on the atmosphere around us.