24 april

Halley’s comet appeared on the eve of the Greater Litany and shone for a week: “such a sign as no man ever saw before”, says the Chronicle. On the Tapestry, men point up at it beside the newly crowned Harold: ISTI MIRANT STELLA, “these men marvel at the star”.

The Anglo-Saxon Chronicle: “Then was over all England such a token seen as no man ever saw before.” It appeared on 24 April, the eve of the Greater Litany, months before the Norman invasion. At Malmesbury the old monk Eilmer, who had once tried to fly from the abbey tower, remembered it from his…

Louis IX of France sailed from Aigues-Mortes, the port he had built for it, wintered in Cyprus and took Damietta in a day. After the disaster in Egypt he stayed four years in the Holy Land, rebuilding the walls of Acre, Caesarea, Jaffa and Sidon.

The sultan of Malindi lent a pilot who knew the monsoon route to India; the crossing took 23 days. Later legend named him as the famous Arab navigator Ibn Majid, but he was most likely a Gujarati.

Charles V’s army forded the Elbe in morning fog and scattered the Saxon army. Elector John Frederick was captured, wounded in the face, and lost his electoral title. Titian painted the victorious emperor on horseback the next year.

Police rounded up more than 200 Armenian writers, clergy, doctors and politicians in the capital and sent them into the interior, where most were killed. Armenians mark the genocide on this date.

Police rounded up about 240 Armenian intellectuals and community leaders in the capital and sent them to the interior; most were killed. Armenians mark the genocide on this date.

The Ottoman government deported the Armenians of Anatolia towards the Syrian desert and had them murdered on the way, in massacres and on death marches to camps around Deir ez-Zor. Estimates of the dead run from about 600,000 to more than a million. Assyrian and Greek Christians were massacred too.

Shackleton, Worsley, Crean, McNish, McCarthy and Vincent sailed the 22½-foot boat, decked over by McNish with canvas and packing-case lids, about 800 nautical miles across the Southern Ocean. Worsley fixed their position with a sextant from a pitching boat on the few days the sun came out.

Vladimir Komarov flew the first Soyuz, launched with known faults. After a day of trouble in orbit its main parachute failed to come out, and the capsule hit the steppe at full speed. He was the first person to die during a spaceflight.

China became the fifth, with a 173 kg satellite that played the anthem The East Is Red from orbit. It weighed more than the other four countries’ first satellites put together.

At 01:06 on Friday 25 April operators began lowering Unit 4 from its full 3,200 megawatts of heat. By 03:47 it stood at half power, 1,600 megawatts, where the test was meant to follow.

Unit 4 was to be shut down for maintenance, and on the way down the staff would test whether the turbine, coasting to a stop, could power the cooling pumps for the minute or so the diesel generators needed to take over. Earlier attempts had failed. What was planned as a day-shift job ended up on…

Hubble goes upHubble Space Telescope

Space shuttle Discovery carried the 2.4-metre telescope, the size of a bus, to about 600 kilometres and released it the next day. Planned since the 1970s, it had waited out the Challenger disaster, spending more than three years in storage.

NASA’s Great ObservatoriesHubble Space Telescope

Four telescopes for four kinds of light: Hubble, Compton for gamma rays (1991), Chandra for X-rays (1999) and Spitzer for infrared (2003). They never all flew at once: Compton was brought down on purpose in June 2000 after a gyroscope failed, three years before Spitzer launched.

President Biden signed the Protecting Americans from Foreign Adversary Controlled Applications Act: ByteDance had 270 days to sell TikTok’s US business, or app stores and hosting companies would have to drop it.