They are far apart because they are different distances away from us. E.g. two galaxies that look right next to each other in the image could be 5 billion and

They are far apart because they are different distances away from us. E.g. two galaxies that look right next to each other in the image could be 5 billion and 6 billion light years away from us, which means 1 billion light years away from each other. Hover over the galaxies in the image here to see the distances (warning: makes sound): https://apod.nasa.gov/apod/ap180305.html https://apod.nasa.gov/apod/ap180305.html