I'm Rory Stewart and I grew up wanting to be a hero and I'm still fascinated by the ideas of heroism.

In my new series, I'm taking in the long sweep of history from Achilles to Zelensky and asking, what is a hero?

Simply doing your job, being a decent human being.

A true hero is someone who just kind of shines by

their own light and that light is to be recognised by others. The long history of heroism with me,

Rory Stewart. Listen on BBC Sounds. Hello, you and this is a very special edition of Inside Science

from the BBC. My name's Adam Rutherford. and this was first broadcast on the 7th of May 2015.

While you're all eagerly awaiting the outcome of democracy, we're running our own version of question time, where you have asked the questions.

We've been soliciting your scientific queries for a few weeks now, things that have been bugging you, making you scratch your

heads. And boy, did you send them in. So we've assembled our regular expert panel covering

a range of scientific disciplines and specialist topics. Unlike question time, these guys have

seen the questions beforehand, so they're not just making it up as they go along. Panel, please

introduce yourselves. I'm Tim Cockrell. I'm a zoologist

and I'm really interested in biodiversity and ecology. I'm Andrew Ponson. I'm an astronomer at

University College London and I'm particularly interested in cosmology, how the universe began and what's in it.

I'm Helen Cherokee. I'm a physicist at University College London, and I study the bubbles

underneath breaking waves.

Okay, thank you, team. Now, we did have dozens, if not hundreds, of questions from our eager

listeners. And I do have to say that the majority of them concerned the astronomical,

the cosmological. So we're going to deal with those first.

Tim, as a resident biologist, I am also, will come to the biological soon enough.

But we're going to start with a question from Peter Gostev. And it goes like this.

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