Meet the panel

Our experts are astronomer Carolin Crawford, nanoscientist Colm Durkan, chemist Ljiljana Fruk, and Haydn Belfield from the Centre for Existential Risk, they're here to answer your questions and to bust some myths...

Chris - Let me introduce the fine panel of people who are going to be answering your questions for you this week Carolin Crawford. She's from the University of Cambridge and she's at the end of the scale which looks at things that are extremely big because you're a space scientist.

Carolin - That's right. Yes.

Chris - We can talk about the universe. Sitting next to Carolin, Colm Durkin who is also from Cambridge University. And he's concerned with the extremely small. I'm intrigued,  down as small as what?

Colm - Small as you can get.

Chris - How big is that?

Colm - Just about the size of atoms and a bit bigger, so pretty small.

Chris - I'll hand you that. Thank you Colm. And Haydn Belfield a newbie on the program as well. Welcome to the show. You're from the Center for Existential Risk. What does that mean and what does that involve?

Haydn - So these are really big threats to international security,  so things like a pandemic or a nuclear war or other happy things like that.

Chris -  And you calculate or look at the likelihood of those things happening and ways to mitigate them and so on.?

Haydn - Yeah very much looking at ways to try and stop them because nobody wants that to happen.

Chris - Thank you very much Haydn. And also here is Ljiljana Fruk, who's a chemist at the University of Cambridge and also a keen cook. Soon soon to be restauranteur.

Ljiljana - Yes yes. And fortunately there are no big extremes in being a cook. Only extremes of pleasure.

Chris - Yeah extreme taste. Now everyone's got a bit of a myth to bust for so many. What's your myth then,  Ljiljana.

Ljiljana - Well I was recently asked about dopamine because I work with dopamine. Dopamine is a hormone that is usually related to all pleasurable things, so people think that this is the hormone of pleasure, but actually it's a hormone of motivation, very important for learning.

Chris - Of course when one eats some delicious food

Ljiljana - Yes

Chris - You are motivated to seek more of the same, you will get a rush. I mean in your brain.

Ljiljana - Yes. So it's a motivational hormone but then you have all kinds of other chemicals which are related, of keeping this happiness high.

Chris - And from very high to very low, very very small. Colm there must be myths abounding in the nano world.

Colm - Oh, there are more than you can shake a stick at, Chris. The one that really irks me is people have been saying for about 20 years that nanotechnologies would be able to make what they call nanorobots second go around the body repairing damaged cells and that is just complete twaddle, I’m afraid.
Chris - Why?

Colm - You basically cannot make things that do what you want at those length scales. You just can't. You can't make a little robot that can move around to any part of the body at will, and repair cells. We can do things that are pretty cool and that are close but not quite that. Not an autonomous machine.

Chris - Does anyone else feel saddened to hear though?

Colm - I know it's very sorry sorry to shatter your dreams.

Chris - I wanted to introduce Carolyn’s myth as well because you must have some massive myths with the universe at your fingertips.

Carolin - Yes but I'm just going to return to an old chestnut, having had this reflected back in me and talking to some schoolchildren this week, which is when they think of astronauts floating around in space I keep getting told there's no gravity in space and that's where they're floating and I just want to remind people there's plenty of gravity everywhere in space. And you know, astronauts aren't that far away if they're in the international space station, only four or five hundred kilometers further out. So yeah they've got reduced gravity but it's only reduced to 90 percent of what we have on earth. So the point is that they're in freefall, they're sitting in the international space station that is falling at the same rate the astronauts around Earth, so there's no kind of reaction force between the two and that's why they're weightless. So there's plenty of gravity in space.

Chris - I must admit I used to find that quite tricky to understand until I actually I met Dave Ansell who we're going to hear from later on in the program who showed me or  introduced  me to the experiment the Isaac Newton did, or his thought experiment about firing a gun, and firing a gun harder and harder and the bullet goes further and further but falls under gravity and eventually is going so fast that it is falling towards the earth all the time and missing the earth's surface. And as a result it's in orbit. And then I suddenly understood; Ah now I understand how it's under the influence of gravity it's always falling and falling and missing.

Carolin - Yes that's exactly what an orbit is. You're just falling towards something. It's just like it's deflecting your route and just continue curving around but you're not being pulled onto something.

Chris - Thank you Carolyn. And Haydn, what have you got for us in the myth department?

Haydn - So the myth I thought I could talk about today was we should be scared of the Terminator. The things we have to be worried about, I think the real risks aren't to do with some unstoppable evil robot thing that's marching towards you and has two hands and scary red eyes.