Author: BBC World Service

With the new Mission Impossible film playing in cinemas, the Unexpected Elements team is channelling Tom Cruise’s energy to see if scientists can push the boundaries of what is considered ‘impossible.’

First up, we fuse medieval alchemy with particle physics and explore a method to turn lead into gold. We then look at the latest research that uses artificial intelligence to help us humans communicate with animals.

We put the spotlight on a favourite trope of science-fiction films – time travel! String theorist Brian Greene of Columbia University explains how going to the past, or back to the future, may or may not be hypothetically possible.

We also ponder ancient auroras, whether ants can plan a Hollywood-style heist, and what it takes to understand our consciousness.    Presenter: Marnie Chesterton, with Affelia Wibisono and Andrada Fiscutean Producer: Imaan Moin, with Alice Lipscombe-Southwell Studio engineer: Mike Mallen

China is aiming to join the small club of nations who have successfully returned scientific samples of asteroids for analysis on earth, teaching us more about how our and potentially other solar systems formed. Tianwen-2 launched successfully this week, bound for an asteroid known as Kamo‘oalewa, which sits in a very strange orbit of both the earth and the sun, making it a “quasi-satellite”.

Last year, scientists including Patrick Michel of the Côte d'Azur Observatory in France, published an intriguing suggestion that Kamo‘oalewa might in fact not be a conventional asteroid, but instead be a small piece of our moon that was ejected when the Giordano Bruno crater formed. In a little over a year from now, we might find out if that is right.

Do you have to hold text at arm’s length to read properly? Qiang Zhang, professor of physics at the University of Science and Technology of China, whose team recently published their demonstration of using a technique from radio astronomy but using optical light. Active Optical Interferometry involves using laser beams to achieve resolutions at distances far in excess of conventional imaging with lenses. As his team showed, and as Miles Paggett of Glasgow University admires, they managed to read newsprint sized letters at a distance of over 1.3km.

Finally, how did the Inca Empire write things down, and who did the writing? It has been thought that ornate threads of strings and baubles known as khipu are how records were made for business and administration, probably by a decimal code of knots in strings. But the exact purpose, nature and any meaning encoded therein, has eluded scholars for decades. Sabine Hyland, an anthropologist at the University of St Andrews, Scotland, has been studying them for years, and recently was granted access to the records of a village, only the fourth known, to have continued a form of the khipu tradition after the Spanish conquest to this day. She believes that they could even provide us in the modern world with valuable climate data.

Presenter: Roland Pease Producer: Alex Mansfield Production co-ordinator: Jazz George

(A Long March-3B Y110 carrier rocket carrying China's Tianwen-2 probe blasts off from the Xichang Satellite Launch Center on 29 May, 2025 in Sichuan Province of China. Credit: VCG/Getty Images)