The plodding photon, or how the speed of light looks sluggish on a galactic scale

According to Albert Einstein’s theory of special relativity, the speed of light (approximately 299,792 kilometres – or roughly 7.5 rotations around the Earth – per second in a vacuum) is the Universe’s speed limit, and therefore the fastest we could ever hope to travel through space. Swift as it might seem, when it comes to traversing the vast expanses between solar systems and galaxies, it’s still very slow-going. Indeed, the nearest galaxy to the Milky Way, Canis Major, is 25,000 light years away. Set to a mesmerising score by the US composer Steve Reich, Riding Light is an illuminating look at light speed, simulating the journey of a photon from the Sun’s surface to just beyond Jupiter’s orbit. For a brisker take, see a condensed, three-minute version of the same video here.

What is it to be Bayesian? The (pretty simple) math modelling behind a Big Data buzzword

If you’ve ever tripped up over the term ‘Bayesian’ while reading up on data or tech, fear not. Strip away the jargon and notation, and even the mathematics-averse can make sense of the simple yet revolutionary concept at the core of both machine learning and behavioural economics. As this video from the YouTube channel 3Blue1Brown skilfully explains, at its most basic, Bayes’s theorem is a tool for assessing degrees of probability based on prior conditions. And there are ways to make it altogether more intuitive than the statistical formulas might suggest. Although the theorem dates back to its 18th-century namesake, the English statistician and philosopher Thomas Bayes, it has gained increasing relevance in the Big Data revolution.

‘They told us to stay put’: the South Korean ferry disaster that sank lives and trust

On 16 April 2014, the ferry MV Sewol sunk off the coast of South Korea, killing 304 people – the vast majority of them high-school students on a field trip. Like many other tragedies, the event made headlines around the world before quickly fading from the international news cycle. In South Korea, however, facts about the incompetence, government failures and lapses in responsibility that led to the Sewol’s sinking emerged slowly over the course of several years, prolonging pain and stoking anger to the present day. The documentary In the Absence by the South Korean director Yi Seung-Jun is a devastating account of the sinking and its aftermath – from the first signs of trouble at sea to the years-long struggle by bereaved families demanding accountability and justice. Combining original material with real-time audio and video of the tragedy, the film offers an extraordinary, chilling account of the consequences of following instructions from inept authorities – and the profound breakdown of public trust that follows such a disaster.

Dadaism ridiculed the meaninglessness of modern life – with captivating results

Dadaism was an avant-garde artistic movement born amid the wreckage of the First World War in Europe and formed in reaction to the perceived meaninglessness of modern life – in particular, of capitalism and its violence. The Swedish artist Viking Eggeling’s stop-motion animation Symphonie diagonale is considered both a Dadaist masterpiece and an early example of experimental animation. Basing the imagery on drawings he created alongside the influential German artist and fellow Dadaist Hans Richter, Eggeling revised and screened several versions of the short from 1922 up until his death in 1925. Shown as a silent film upon its release, this version of Symphonie diagonale features an original score, exclusive to Aeon. The contemporary Illinois-based composer William Pearson intends his music to react to Eggeling’s original vision in both style and composition, with playful, occasionally mechanical organ sounds, and melodies forming in sequence with the visuals emerging on screen.

The eerie serenity of a summer’s day by water, before one of history’s bloodiest battles

‘We laugh and for one heartbeat forget to be afraid…’

The Battle of the Somme, fought by French and British forces against the German army in northern France in 1916, was one of the bloodiest in history. It lasted 140 days and resulted in more than 1.5 million casualties. The Scottish artist Herbert James Gunn (1893-1964) served as a rifleman, and painted The Eve of the Battle of the Somme in the field, just hours before the attack on ‘the Boche’ began on 1 July 1916. He depicts a scene of eerie serenity: young men relaxing by water on an idyllic day, watched by a menacing line of army tents, a foreshadow of the unfathomable bloodshed that followed. Commissioned by the UK charity The Poetry Society, the short film The Big Push reinterprets Gunn’s painting through impressionistic paint-on-glass animation. It is set to an eponymous poem written and read by the contemporary Scottish poet John Glenday, inspired by Gunn’s painting.