What are gravitational lenses?
Look here: http://zebu.uoregon.edu/~soper/Mass/gravlens.html
I saw the page that you gave.But in the image that was released by Nasa as reality ,I can't undestand anything.
See the two bright stars really close to each other on the left and third one a little farther away. That's really one star and some other star serving as a source of gravity. In the middle bottom part an object looks like a galaxy with a big star in the middle. That's the last example they mention. There are others but these are the most noticable.
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