Israel says it has assassinated Ali Larijani, the most powerful man in Iran and the country’s de facto ruler. The head of Tehran’s National Security Council – whose family is sometimes referred to as the “Kennedys of Iran”, and who is said to have orchestrated the massacre of tens of thousands of Iranian protesters in January – was reportedly killed in missile strikes overnight. Some of the cases in the deadly meningitis outbreak in Kent have been confirmed as meningitis B, a bacterial strain that most people are not vaccinated against. Routine vaccination against MenB for babies was only rolled out by the NHS in 2015, meaning most people are not immune. Oxford astronomers believe they have discovered a new type of planet around 35 light-years from Earth. Unlike rocky or gaseous worlds, the planet, known as L 98-59 d, is covered with a “global magma ocean” that lies beneath a highly sulphurous atmosphere with temperatures a toasty 1,500C.

The conflict with Iran started with vague war aims. It now has a single “clear and overriding objective”, says Gideon Rachman in the FT: “reopen the Strait of Hormuz”. Now that this narrow waterway – through which 20% of the world’s oil exports pass – has been effectively closed by Tehran, Donald Trump cannot simply declare victory and walk away. In the short term, the longer it remains closed, the greater the risk of global recession. And in the longer term, Iran now knows that its control over the strait gives it a “stranglehold over the world economy”. Even if it can be persuaded to relax its grip in the coming weeks or months, it can always “tighten it again in future”.

Iran’s advantage is asymmetric: a handful of attacks on oil tankers, and the threat of more, has been enough to persuade ship owners and crews to steer clear. And even if the US and Israel obliterate Tehran’s missile launchers, the Islamic Republic has plenty of other options, including deep-sea mines, inflatable boats equipped with limpet bombs, and drones. Trump has asked allies to send their navies to help break the blockade. “He has even appealed to Beijing.” But while Britain, the EU and others have a significant interest in the strait, after a year of tariffs, threats and insults they’re reluctant to risk their own forces to solve a problem they didn’t create and which the US navy can’t fix alone. Meanwhile, Iran’s Gulf neighbours face a dilemma: try to reach an accommodation with the current leaders, or press harder for regime change, with all the dangers that brings. Iran is taking a battering. But having demonstrated the power of its most potent geopolitical weapon, it may emerge stronger than ever.

🚢💣 Tehran has spent decades preparing to block the strait, says Caitlin Talmadge in Foreign Affairs. It amassed approximately 5,000 sea mines, including hard-to-find “seabed influence mines” that detonate in response to acoustics, magnetics or pressure (rather than contact). It has multiple means of delivering these mines, including midget submarines and hundreds of small boats, many of which may be hidden in networks of impregnable caves and tunnels. How much of this arsenal has survived the US and Israeli bombardment is unclear. But even a modest mine-laying campaign could be enough to stop tankers entering the strait.