Astronomy textbooks typically present galaxies as staid, solitary, and majestic worlds of glittering stars. But galaxies have a dynamical side. They have close encounters that sometimes end in grand mergers and overflowing sites of new star birth as the colliding galaxies morph into wondrous new shapes. NASA released these images to celebrate the 18th anniversary of the Hubble Space Telescope launch.

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More Pictures of Galaxies in Collision

source:http://geology.com