After president Joe Biden's faltering performance in the TV debate with Donald Trump there are calls to replace him. Also, Iranians are voting to elect a new president to replace Ebrahim Raisi who was killed last month in a helicopter crash, and why radioactive rhino horns help conservation efforts.

Joe Biden and Donald Trump will be using the stage at the CNN debate in Atlanta to try and convince voters to back them in November. Also: Palestinians flee Gaza City's Shejaiya area amid heavy bombardment, and Elon Musk's SpaceX hired to destroy International Space Station.