Galactic Silhouettes

1. What are the interesting features in this picture?

The spiral arms of the foreground galaxy appear dark where the dust is silhouetted against the light from the more distant galaxy. The bright blue stars forming a pinwheel shape near the center of the foreground galaxy have formed recently from interstellar gas and dust.

A small, red patch near the center of the image is the bright nucleus of the background galaxy. It is reddened for the same reason the setting sun looks red. When light passes through a volume containing small particles (molecules in the Earth's atmosphere or interstellar dust particles in galaxies), its color becomes redder.