Quadruple vision... The Hubble telescope has imaged
a spectacular example of “gravitational lensing” (see image at right, click to embiggen). The yellowish supernova seen four times is actually
behind the closer galaxy that appears to be centered between them. The gravity field of that galaxy is acting like a lens, bending the light from the supernova around itself so that we see four different images of the supernova. This is a phenomenon Einstein predicted as a consequence of his general relativity theorem...
