Others have mentioned that light doesn't scatter in a vacuum.

However, light gets dimmer with distance. according to an "inverse square law". This has at least two implications.

• Astronomers must use wider telescopes and leave the camera open over a longer time to capture enough light to see stuff far away.

• Astronomers can use increasing dimness at greater distances to measure distance. In 1924, Edwin Hubble used the increasing dimness of Cepheid variable stars in the Andromeda Galaxy to claim the Andromeda nebula was actually another galaxy outside the Milky Way Galaxy. Source