Neptune gives out about two and a half times as much heat as it gets in the sun.

It's really just about the availability of material.

Oh yeah, Neptune, that's got stuff going on.

Hello and welcome to the supermassive podcast from the Royal Astronomical Society with me,

science journalist, Izzy Clark and ast astrophysicist, Dr. Becky

Smethurst. We've done it. It's taken us all year, but we've finally reached the final

planet in our solar system, Neptune. My second favorite planet, obviously, after Saturn,

but I just, I don't know what it is about Neptune. Like, I think it's the

colour. I'm just, I'm just a sucker for a blue and it's just the most gorgeous, deep,

sea-colored blue as well. It's just right. I think just the color goes with its name, right? I even

painted my nails. Oh, have you? Like, Neptune blue for you is? Yeah, just in honor of this episode.

Saturn's out there getting jealous like, Becky is talking about another planet?

And I don't know how I feel about this.

So coming up, Lee Fletcher from the University of Leicester is back to cover the basics of Neptune.

And Carolyn Kennett, chair of society for the history of Astronomy, tells me about its controversial discovery.

Oh, intrigue. I like it.

But as always, Dr. Robert Massey, the Deputy Director of the Royal Astronomical Society, is here.

So, Robert, how big is Neptune?

It's always good to start with a question I can answer there, is he, I think. So yeah, so quite big is the answer. It's the fourth largest planet in the solar system. Still a gas giant or it's an ice giant. 49,000 kilometers across, which means it's a bit smaller than you're actually, but more massive. And you could fit 58 Earths inside. And it's really far away as well, which is a crucial point.

Four and a half billion kilometres. So although it's quite big, it always looks really small in a telescope. And you actually need quite good conditions to see it as not looking like a star. So the most you get to see with most telescopes on Earth is a little tiny blue disc. And if you're very lucky, it's Big Moon Triton. And we did see it. I don't know if you remember when we visited Hursman, so we saw it there because it was just trailing along behind, I think it was further along than Saturn was. So we have, we, we, we, we, are three of us have seen it. You must have seen it as like, yeah. I've seen it as like a blue dot. And I'm like, oh yeah. Exactly. If I squint, am I seeing it? Is that?

I love it if you use like Stellaria, but it's like Neptune is there. You're like, is it? Okay. I always end up trying to take a photo with my phone, like a night mode shot to be like, is it there? But then so many stars pop up that I'm like, I still don't know where to look. Well, cheers, Robert. We'll catch up with you later in the show for some more questions and those all-important stargazing tips. Okay, so that is the size of Neptune covered. But what is it like as a planet? And how much do we know about it, given that only one spacecraft, Voyager 2, has ever passed this ice giant. A travesty. A real travesty. Well, Lee Fletcher, Professor of Planetary Science at the

University of Leicester, was featured in our Uranus episode, and this time I caught up with him

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