Take a shimmering, surreal swim with what might be the Earth’s oldest animals

Until recently, mainstream thinking in biology had long held that sponges were the first animal to emerge on the evolutionary tree. But over the past decade, a new wave of research argues that ctenophores, a phylum of sea invertebrates found in saltwater around the world, might be our oldest and most distant relatives. Featuring entrancing camerawork of ctenophores recorded by the US artist Charles Lindsay at Hope Island in British Columbia, Canada, Fieldwork: Comb Jellies offers a close-up look at the translucent creatures that have prompted the tree of life to be redrawn. As the jellies move across the frame, the quick movements of the fused cilia (or ‘comb rows’) they use to propel themselves diffracts the light into a rainbow, giving them an ethereal glow. Combining audio recorded at source with processed sounds from a variety of underwater microphones, Lindsay’s glitchy and immersive sound design gives the impression of a deep-sea swim on an otherworldly planet.

For more on ctenophores, read the Aeon essay Aliens in Our Midst.

From imbalanced humours to brain chemistry – on the evolution of melancholy

The Ancient Greeks blamed sadness on bodily humours called ‘melaina kole’ (black bile). Today, clinical depression is often understood as an imbalance of brain chemicals – although this is a paradigm that many experts believe is overdue for an update. This animation from TED-Ed offers a brief examination of the history of melancholy, scoping how philosophers, poets, writers and scientists have envisioned and altered our understanding of the experience across the ages.

The meanings and mysteries of the iconic Sutton Hoo helmet brought vividly to life

The early Anglo-Saxon artefact known as the Sutton Hoo helmet has, since its origins in the 7th century, passed through many incarnations, including: exquisite armour, long-dormant burial object, astounding archeological discovery and high-stakes puzzle. Today, the Sutton Hoo helmet – so named for the site in the English county of Suffolk at which it was discovered in 1939 – lives on as one of the British Museum’s most famous pieces. In this video, Sue Brunning, curator of the museum’s European Early Medieval Insular Collection, examines the iconic object, revealing the multitude of meanings and mysteries it holds. Through her investigation, Brunning brilliantly captures how history is an ever-fluid work in progress, being made and remade as new discoveries are brought – often quite literally – to light.

When medicine offers no relief, a biohacker begins a radical self-experiment

In 2015, the US scientist, artist and self-described ‘biohacker’ Josiah Zayner undertook a controversial project to help resolve his lifelong gastrointestinal issues. The plan was to replace the vast colonies of microbiota on and inside his body via transplants from a healthy donor – and then document the proceedings. Although an accomplished biologist with a PhD in biophysics and two years as a NASA researcher under his belt, Zayner’s endeavour was frowned upon by much of the scientific community, with critics condemning the project for operating outside the normal boundaries of bioethics. Especially controversial was Zayner’s plan to self-administer a faecal transplant – a risky procedure usually reserved for potentially fatal conditions. In their documentary Gut Hack, the filmmakers Mario Furloni and Kate McLean follow Zayner’s fascinating, radical and not-for-the-squeamish quest for relief. In so doing, they also confront deeper issues of ethics and autonomy at the core of contemporary science.

Against ‘beauty’ in science – how striving for elegance stifles progress

That there is an inherent ‘beauty’ and ‘elegance’ to the laws of nature is a view that permeates the field of physics. But, according to the German theoretical physicist Sabine Hossenfelder, the notion that the further you peer into reality, the easier the equation gets, has no basis in reality. Indeed, since the mid-20th-century, the maths of physics has become increasingly knotty, even as many physicists have continued to search for a path back to simplicity. In this interview with Robert Lawrence Kuhn for the PBS series Closer to Truth, Hossenfelder makes the case that this fixation on beauty isn’t just misguided – it’s stifling scientific progress.