Are you still with us?

Are You Dead?

That’s the name of an app that’s gone massively viral in China. Every two days, you click a green button to confirm you’re alive and well – but if you miss it, an emergency contact is alerted.

The app is aimed towards those who live alone, so it’s got us contemplating the science of connection and loneliness. First, we take a look at the most isolated trees on Earth and how they act as important recorders of history. We also discuss NASA’s space probe Voyager 1, and how we can connect with a device that’s 25 billion kilometres away from us.

We’re joined by glaciologist Liz Morris, who shares what it was like to do research far from civilisation, in Antarctica.

Then we reunite with a species that we thought was lost for ever, and answer an important question: just how big can spiders get?

All that, plus many more Unexpected Elements.

Presenter: Marnie Chesterton, with Candice Bailey and Ogechi Ekeanyanwu Producers: Ella Hubber, with Lucy Davies, Imy Harper, Tim Dodd, Sophie Ormiston and Margaret Sessa-Hawkins