How quantum superposition could unravel the ‘grandfather paradox’

The ‘grandfather paradox’ has long been one of the most popular thought experiments in physics: you travel back in time and murder your grandfather before he’s ever born. If you’ve killed your grandfather, you’ve prevented your own existence, but if you never existed, how could you have committed the murder in the first place? Some physicists have avoided the question by arguing that backwards time travel simply isn’t consistent with the laws of physics, or by asserting a ‘many worlds’ interpretation of the Universe. But could the concept of quantum superposition remove what seems so paradoxical from this tale of time travel and murder once and for all?

An ageing philosopher returns to the essential question: ‘What is the point of it all?’

‘Being 97 has been an interesting experience.’

By the time of his death, the US philosopher Herbert Fingarette (1921-2018) had lived what most would consider a full and meaningful life. His marriage to his wife, Leslie, was long and happy. His career as professor of philosophy at the University of California, Santa Barbara was both accomplished and controversial – his book Heavy Drinking (1988), which challenged the popular understanding of alcoholism as a progressive disease, was met with criticism in the medical and academic communities. In a later book, Death: Philosophical Soundings (1999), Fingarette contemplated mortality, bringing him to a conclusion that echoed the Epicureans: in non-existence, there is nothing to fear. But as Being 97 makes evident, grappling with death can be quite different when the thoughts are personal rather than theoretical. Filmed during some of the final months of Fingarette’s life, the elegiac short documentary profiles the late philosopher as he reflects on life, loss, the many challenges of old age, and those lingering questions that might just be unanswerable.

Magnetic and majestic: visualising the powerful storms hidden from human view

Violent plasma explosions from the Sun’s surface – known as coronal mass ejections – reverberate to the farthest reaches of our solar system. However, due to the Earth’s protective magnetosphere, most people don’t take note of these events unless a particularly powerful solar flare disrupts radio signals or produces colourful aurorae near the poles. Created as part of an art installation, this inventive, visceral short uses data collected from the University of Alberta’s CARISMA radio array to sonically and visually interpret a geomagnetic storm high in Earth’s atmosphere. Manifesting the data as a dynamic sculpture, the digital rendering captures the volatility of these usually unseen and unheard phenomena, hinting at their potentially destructive powers.

Chocolate, monsters and mothers – surreal glimpses of our most common dreams

While your dreams might feel strange or random, and unique to you (if you even remember them at all), an ongoing project by the US psychologist Kelly Bulkeley offers some insight into our most common dream experiences. Since 2009, Bulkeley has encouraged people around the world to submit the contents of their dreams to his searchable online Sleep and Dream Database, which has thus far collected accounts of some 30,000 dreams. This appropriately surreal short video imagines a composite dream as it divulges some of the fascinating insights from the database, including the food you’re most likely to encounter while sleeping (chocolate), and the person you’re most likely to come across (mother, of course).

‘I want you to live forward, but see backward’: a theoretical astrophysicist’s manifesto

The theoretical astrophysicist Katie Mack at North Carolina State University is known for her work on dark matter, as well as her science-outreach efforts. In this short video essay, Mack weaves together cosmology and poetry as she details her personal mission to make her work enhance and challenge our understanding of the Universe, and by extension, ourselves. She writes: ‘I want to make you wonder what is out there; what dreams may come in waves of radiation across the breadth of an endless expanse; what we may know given time; and what splendors might never, ever reach us.’