headed to a fifth straight term as prime minister, and poised to soon surpass founding father david ben-gurion one of the naon's founders, as the longest serving leader ever. for the pbs newshour, i'm john yang in tel aviv. >> woodruff: unlikely as it sounds, we now have an image of that invisible space anomaly, a black hole, a cosmic abyss with gravity of such intensity that nothing, not even light, escapes it. a team of astronomers made the image public at a press conference in washington, d.c. this morning. we start our report tonight with this background video from thenc world scfestival and oficed by its co-founder, brian greene, professor physics at columbia university. it's the latest in our weekly science and technology series, "t leading edge." >> about 100 yeans ago, albert in gave us a new description of the force of gravity in which gravity exerts its influence through warps and curves in the fabric of space and time. just a couple of years later, karl schwarzschild, he was a german astronomer, who was stationed n the russian front during world war i and charged with tackling artil