After collecting data for more than twelve years the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) announced it may have detected new kinds of gravitational waves caused by colliding supermassive black holes. Professor Chiara Mingarelli of the University of Connecticut tells Roland Pease why this is such an exciting discovery.

Supermassive black holes are at the heart of galaxies and they are the engines of quasars, the brightest light sources in the heavens that can be seen across the expanse of the Universe. A team including Professor Xiaohui Fan of the University of Arizona has identified the oldest quasar in the universe.

The SARS-CoV-2 virus looks much like bat coronaviruses, but the mostly likely route into humans involved some other infected animal. Roland talks to Dr Dalan Bailey of The Pirbright Institute about how he has been looking for possible intermediaries.

A new study that looks into the genetics of twins and their families in Iceland shows that identical twins aren’t really identical. Kari Stefansson of the Icelandic genome company, DeCode, explains that the differences can appear when the twins are at the embryonic stage.

And , When it comes to speed, humans have got nothing on cheetahs - or greyhounds, kangaroos or zebras for that matter. It’s over long distances we really come into our own: when running for hours or even days, our body structure and excellent sweating skills make us able to outpace much faster mammals.

But what are the limits of human endurance? Can we run ever further and faster, and what’s the best diet to fuel such ambitions?

This week’s questions come from two CrowdScience listeners in Japan who already know a fair bit about stamina, having run several marathons and long-distance triathlons between them. We head to Greece, legendary birthplace of the marathon, to witness an even more arduous challenge: hundreds of athletes following in the footsteps of the ancient Greek messenger Pheidippides, to run an astonishing 246km across the country. The ever-so-slightly less fit CrowdScience team do our best to keep up, and try to discover the secrets of these runners’ incredible endurance.

(Image: Representative illustration of the Earth embedded in space-time which is deformed by the background gravitational waves and its effects on radio signals coming from observed pulsars.