Gravitational lensing en mass, galactic cluster:

Originally posted by sonhouse
http://antwrp.gsfc.nasa.gov/apod/astropix.html
I wonder what the night sky would look like if you were in the middle of this cluster?

... and what an early civilization would build their knowledge of astronomy?

Originally posted by FabianFnas
... and what an early civilization would build their knowledge of astronomy?

If you are talking about the gravitational lensing we see, inside the cluster you would not see such, since it would only be visible as an optical distortion from a long distance away, like billions of light years. Inside the cluster you might see microlensing but not macrolensing like in the photo.

BTW, here is a permanent link(I forgot that link on the first post would only be up for a day): http://antwrp.gsfc.nasa.gov/apod/ap100620.html