* The battle for the UK Tory leadership * Killing of Al Qaeda leader Ayman al Zawahiri *

Pope Francis has hinted that he might retire. He would follow Pope Benedict, who is now 95. The election of a successor to Francis would mean the Catholic Church would have three living popes, and that makes some people nervous. Jan Machielsen, senior lecturer in early modern history at Cardiff University explains why.

* The Artemis moon landing project *

* Why ants are the mini-engineers vital to our survival #

* Discovering the secret lives of cheetahs * Orban in Vienna *

* Personalised Precision Medicine: how better testing could revolutionise healthcare *

* Opposition activists executed in Myanmar *

* ESA Gaia Mission: "A billion stars in a billion pixels" *

* How Ukraine is becoming a proxy war *

* Dealing with the heat * Iran, Russia and the changing balance of world powers *