Why does the night sky look a bit different after 100 years?

Question

I am using Heavens Above interactive Skychart and noticed that if you move the year by 100 year increments, the night sky changes, but not so much. What causes this?

In: Planetary Science

Answer 1

All of celestial bodies including Earth move in space. Earth is not in the same location that it was 100 years ago and neither is anything else. This changes the way the night sky looks.