Episode 320 Was Mars once home to alien life? The evidence is stronger than ever, since NASA’s discovery of rocks marked by patterns similar to those made by microbes on Earth. Found in an area now named Bright Angel, these rocks give us a tantalising insight into Mars’ ancient past - but just how definitive is this finding? It’s long been thought that when the Roman Empire withdrew from Britain in the early 400s, the result was chaos and economic collapse. But a new archaeological discovery suggests that’s not the case. Signs show a boom in the ancient metalworking trade around that time. Do we need to rethink this period of our history entirely? We’re constantly discovering more and more ways to boost our microbiome and improve our health – everything from eating more fibre and fermented foods to having pets and embracing dirt. And now there’s something else to add to the list: weight lifting. After being put on a weight training programme, a group of sedentary adults showed a surprising uptick in beneficial gut bugs. But how are the two things connected? Chapters: (00:00) Intro (01:19) Strongest evidence for past life on Mars (14:55) The Romans impact on the British economy (23:19) Link between exercise and your microbiome Hosted by Rowan Hooper and Penny Sarchet, with guests Mike Marshall, Mike Tice and Sanjeev Gupta. To read more about these stories, visit https://www.newscientist.com/Get your ticket for New Scientist Live here: https://live.newscientist.com/ Learn more about your ad choices. Visit megaphone.fm/adchoices

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“What did the council decide on item 42?” — answered with the speaker and the moment.