Derivations of this phenomenon may assume that objects satisfy the “singular isothermal sphere” profile. The KSB (10[1])method is used to combat the PSF uncertainty produced in this phenomenon. The background distribution (-5[1])of dark matter can be found by averaging the orientations of galaxies due to the shear produced by this phenomenon. (10[1]-5[1])The observation of the “Twin Quasar” (10[2])confirmed (10[1])Fritz (10[2])Zwicky’s (10[2]-5[1])prediction of this (10[1])phenomenon. (-5[1])The quantity (-5[1])[read slowly] (-5[1])“four times big G times mass (-5[1])over radius (-5[1])times c-squared” equals this phenomenon’s angle (10[2])of deflection. When (10[1])a source, (10[1]-5[1])observer, (10[1])and intermediary are (10[5])all aligned, (10[1])this phenomenon (10[2])can produce (10[1])a (10[3])“halo (10[3])effect” (-5[1])called (10[5]-5[2])Einstein rings. For (10[2])10 points, name (-5[1])this phenomenon in which astronomical bodies bend (-5[1])the (10[2])path (10[2])of (10[11]0[5])light. ■END■