© NASA/ESA Hubble Space Telescope.
The brane annihilation that ends inflation in the brane inflation model could produce giant strings that stretch across the entire universe. These cosmic strings are very massive because a string's mass scales with its length. If the cosmic string happened to pass between us and a background galaxy, we would see a double image of the galaxy produced by the gravitational lensing process explained in Units 3 and 10. The signature of cosmic string lensing is the discontinuous break between the two galaxies in the simulated data shown here. (Unit: 4)