Uranus and Neptune are the Ice Giants of the Solar System. We are joined by Naomi Rowe-Gurney,  who specializes in studying their atmospheres to uncover their mysteries, from their diamond rains to their likely funky smells!

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Compisite view of Uranus (left) and Neptune (right) as seen by Voyager 2 in 1986 and 1989 respectively. NASA/JPL-Caltech

Chris
Today we are joined on the Astroholic explains by another special guest.

Alfredo
It is been a season of wonderful guests. Please special guests Introduce yourself.

Naomi Rowe-Gurney
Um, hi, I’m Naomi Rowe-Gurney and I am a PhD student at the University of Leicester.

Alfredo
Hello, Naomi.

Chris
Hello Naomi.

Alfredo
So what do you study?

Naomi Rowe-Gurney
I study the ice giants, to Uranus and Neptune. I studied their atmospheres. I looked at data from the Spitzer Space Telescope, which is this telescope that’s following us in space. It looks in the infrared. So it looks like the heat that comes from atmospheres. And I take some of that data and kind of look at what’s inside Uranus’s atmosphere and also like how hot it is, etc.

Alfredo
That is wonderful. Oh, my God. Spitzer was just retired this year, and it’s heartbreaking.

Naomi Rowe-Gurney
It was in January. So sad. Yeah, my instrument hasn’t worked since 200… a long time ago, it broke a while back.

Alfredo
Fair enough. But to be honest, is a mission that was sent to space in the first decade of this century.

Naomi Rowe-Gurney
2003?

Alfredo
Yeah, so it worked for a very, very, very long time. Way past its specifications.

Naomi Rowe-Gurney
It was a success.

Alfredo
Definitely. So tell us a little bit about what you do, and what kind of part of the atmosphere you you’re looking at.

Naomi Rowe-Gurney
So I look at the bit in the middle. So a lot of people look at stuff like really deep so the troposphere, like down like into the depths where all of this like crazy chemistry is happening. Or some people look at the top where there’s the sun is hitting it and there’s like aurora and stuff. Whereas I look in the middle so it’s the stratosphere and the upper troposphere, which is where all of the kind of chemical reactions happen because of the sun. So photodissociation of methane mostly. So methane is what makes the both the ice giants really blue. And when it breaks down, it breaks into these like other hydrocarbons and then I look at like the little wiggly lines that show which hydrocarbons..

Chris
This is very exciting and this is the perfect place for me to jump in.

Alfredo
Okay! Let’s brace ourselves to whatever question Chris asked concocted for us. I’m very glad that you could join us because apparently I needed the help from somebody with expertise on ice giants before this so glad that you can help.

Chris
So you’re either gonna love this or absolutely hate it or just roll your eyes and leave the room but here we go.

Alfredo
I’m gonna go and grab the Nerf gun.

Chris
Okay. In 1967 John Lennon and Paul McCartney of Beatles fame wrote a song titled Lucy in the Sky with Diamonds. A number of conspiracies arose surrounding the song with a popular one taking the acronym of the song title, and the surreal song lyrics to refer to the drug LSD.

Alfredo
okay

Chris
But they was allegedly false because Lenin confirmed that the lyrics in the title were inspired by a drawing that his child did. And also from Lewis Carroll’s Alice in Wonderland.

Unknown Speaker
I’m really curious, where are you going with this?

Chris
So I’m putting this out there right now. Okay, their explanation was a lie. Because the Beatles were simply covering up their prophetic ability that one day the LCLS [Linac Coherent Light Source] would discover a kind of sky filled with diamonds far away in our solar system. So please tell us more about the recent report about diamonds on the ice giants Neptune and Uranus.

Naomi Rowe-Gurney
Wow, that was amazing. Wow, I wish every question was posed that poetic way I really do.

Chris
Also, if the Beatles ever listened to this, please don’t sue us.

Naomi Rowe-Gurney
Yeah, they might, they might! I get this question all the time. All the time.

Alfredo
Awesome.

Naomi Rowe-Gurney
Yeah. So people I don’t know when this came out, but it was in a lot of popular magazines. Obviously people like sparkly things. So when diamonds are involved like people go crazy. So, when it came out is it’s just a paper that did some chemistry. So like in the lab chemistry, they like played with the hydrocarbons that are present in the ice giant atmospheres and, like condensed them and made the environment the same as, like, pressures that were really deep in the atmosphere (way deeper than I study) in the atmospheres of both Uranus and Neptune. And what they found was they were creating diamonds at these pressures with these hydrocarbons. So there is every chance that in obviously the same conditions at the ice giant, there is lots of diamond creation happening.

Chris
That’s absolutely just mind blowing to me.

Naomi Rowe-Gurney
Big diamond

Chris
I was gonna ask as well, like, do we have any idea like what they’d be like tiny molecule size or…

Naomi Rowe-Gurney
They start that way but then they accumulate because obviously you’re squishing things further and further down, they’re just gonna end up like squishing into, like giant diamonds! Should be so cool to see.

Chris
Wow!

Naomi Rowe-Gurney
Yeah, this is at a depth that you would never get to as a human. So there’s no way you would ever find this out. It’s all always gonna be theory.

Chris
It’s never it’s never going to be the ideal place to go and find diamonds.

Naomi Rowe-Gurney
It’s not not a mining opportunity. Definitely not.

Alfredo
Another this this is all theoretical. But do you think there is anyway to see any indirect evidence from atmosphere observation? Like you mentioned photodissociation of hydrocarbons, and that’s what you work on. Do you think there’s… To be honest, I don’t do much chemistry or astrochemistry.

Chris
Are you simply asking if when you look at the planets, would they be shiny other than other planets?

Alfredo
No, no Sweetie.. there’s no light just like…

Naomi Rowe-Gurney
I mean, would you be able to see evidence of diamonds in the higher atmospheres where you can do observation

Alfredo
Yeah, or something like that could be associated. I know that it requires enormous pressure. It’s probably it’s just too deep. But I was just thinking: How high do the little seeds diamonds form? Do you really need incredibly high pressure?

Naomi Rowe-Gurney
Yeah, you need really high pressure. So the pressures that I’m looking at are like, up to 100 bars, that’s like, pretty… it’s not that deep. You know? [Diamons are] like really really far in, I don’t even know the pressures that they were doing it was like more like 6000 bar or something ridiculous.

Chris
what does bar refer to, sorry?

Alfredo
A bar is a unit of pressure.

Naomi Rowe-Gurney
Yeah.

Chris
Okay.

Alfredo
I always forget the, the conversion. Yes, I was literally I was thinking that like is it…

Chris
So how much is a bar?

Alfredo
A bar is about one atmosphere, which is about the atmosphere you get at sea level on Earth. So, okay, so we’ll be talking about hundred bars is 100 times… 100 atmospheres and diamonds who will require something like 60 thousands atmospheres

Chris
really?

Naomi Rowe-Gurney
like a crazy amount of pressure.

Chris
I mean, this is going slightly off topic, but still talking about diamonds just briefly. So is that just because the diamonds on Neptune and Uranus, they form because of that pressure and can that pressure exist inside Earth where we get diamonds?

Naomi Rowe-Gurney
Yeah, so this will be a similar setup but it will probably be a different pressure actually because you have to take into account like the the temperature as well. So I mean pressure and temperature kind of go hand in hand but there it’s so cold out in Uranus and Neptune is obviously going to be like magnitudes different to here. So

Alfredo
That was super cool. Oh my god.

Chris
Sorry, I just I’m just I’m grabbing my list of I only have it like about four or five questions, but hopefully that will spark off bigger conversations as well

Alfredo
Go ahead.

Chris
This one is another one the headlines I remember headlines just went wild with no kind of apologize for asking it again. But it’s the subject of Uranus smells of farts.

Naomi Rowe-Gurney
Oh, yeah.

Chris
Tell us more about this. Is this common in ice giants? What’s going on there?

Naomi Rowe-Gurney
Oh, funny story about this actually… The guy who found this out is my supervisors supervisor.

Chris
No way.

Alfredo
Your academic granddad.

Naomi Rowe-Gurney
Yeah, academic grandpa!

Alfredo
Awesome!

Naomi Rowe-Gurney
Yeah, he found this out. Obviously it’s H2S that is observed at Uranus and it never been observed before. And so he sent it out to the press. And in the press came back with all of this you radio smells like farts and it was all over the internet and he was so unhappy. He was so angry, everybody kept on sending him like the articles like over and over again just to piss him off more and it was hilarious.

Alfredo
I would admit that that was the title of my article as well. But I would I did point out that hydrogen sulfide only smell like fart in I think less than 5 parts per million concentration and over that before kills you, because it will make you really sick is people described as being sickly sweet.

Naomi Rowe-Gurney
Oh, that’s weird.

Alfredo
I cannot remember the concentration on Uranus. I think the concentration was probably this will be a sniff and you’ll be dead, but

Naomi Rowe-Gurney
Probably

Alfredo
You will probably die not thinking like “oh my god, Uranus really smells a fart”. You’re probably thinking like, “Oh my god, this is so like molasses sweet”. And then when you’re dead.

Chris
Smells amazing. Dead.

Naomi Rowe-Gurney
Yes! Maybe one day we’ll know what Uranus smells like, maybe one day but he goes and gets like a box and like puts it in… I don’t know how would you figure out what it smells like?

Alfredo
I don’t know like he will need… I don’t know…

Chris
It’s like it’s like years ago when people on eBay were selling bottles of fresh air from the countryside.

Alfredo
The fact that it was only discovered what a year and a bit ago, this important component of the atmosphere, how, how much or little do we know about the atmosphere of Uranus and Neptune?

Naomi Rowe-Gurney
Actually very little. I mean, we’ve only visited both planets once. And so we’ve been to both of them but only for like brief flybys with Voyager 2 and that was in 1986, fieriness in 1989, for Neptune. So there’s a long time ago before I was born, it already left Neptune and it was traveling into like interstellar space. So all have the data that we get is either from Earth based or like space based telescopes that are near Earth. So we can’t really figure everything out. I mean, you can’t observe things like like inert gases like noble gases from faraway because they don’t react. And the only way that we can see gases from a distance is because they react with the sun or with light that we can observe them. So…

Chris
That’s fascinating. I never thought of that. I never really thought of that. I mean, obviously, I’m not a scientist, but that’s something that I never really considered how the Sun would factor into detecting, well, either certain elements or compositions of atmospheres on other planets.

Alfredo
Yes, the Sun plays a major role because in the reaction also changed molecules and everything. So I know a little bit more than that on Saturn. Thanks to both Hubble and Cassini. We’ve seen so much of how the seasons change and how the color on the planet change. So guess what? Uranus and Neptune are much further out. So th effect will be less but also different given that the probably have different composition

Naomi Rowe-Gurney
We don’t know much about what effect the Sun has on them because we haven’t been able to observe that effect. And everything that we do observe is kind of like small snippets and time so we don’t have a like a comprehensive study of like the entire like as it spins and as it goes around the sun, and obviously it takes like 89 years for Uranusa to go around the sun, it takes 164 years something for Neptune to go around the sun. So we have these huge, like years that we have to take into accounts of seeing a seasonal change is like a lifetime journey.

Chris
This ties quite nicely into another question I had…

Alfredo
You always say this and then it’s always a bit of a stretch.

Chris
I don’t think this is it.. because we’re talking about seasons, or things like that.

Alfredo
Okay.

Chris
Because I think it was within the last few months. A story talked about storms on ice giants that lasted for decades.

Naomi Rowe-Gurney
Yeah.

Chris
Why did why do they last so long?

Naomi Rowe-Gurney
That is a good question.

Alfredo
I have no clue.

Naomi Rowe-Gurney
Um, they last a long time, I think because of the size of the planet. And also there’s a lot of gases, a lot of atmosphere. And so like the atmosphere of Earth is like really, really tiny compared to the huge atmospheres on the gas giants. I mean, that’s why they call gas giants because they literally are just atmospheres, like huge ones. And so with a lot more gases and a lot more light from not as much light from the sun, everything is a little bit kind of delayed than on earth like everything happens very quickly on earth we got like land masses and ocean and like not a lot of gas to play with where it’s there’s a lot more.

Chris
Would it tie into.. This mean just like trying to think of theories now! Because on earth obviously we have the seasons and they occur cosmically regularly. There’s like four months per season. Three months per season….

Alfredo
Right. Three months per season on Earth.

Chris
Yes. Right. Three months per season. So that’s um, it’s, you know, we go around the Sun very fast compared to planets further out in the solar system.

Alfredo
Yeah

Chris
Our weather systems. change a lot is it with the storms maybe lasts so long on planets further away? Because seasons don’t change as often as ours?

Naomi Rowe-Gurney
True, although on Uranus the season is super extreme because it’s rotating on its side. So for like half of the year, its poles are facing the sun and then the other half of the year is equator facing the sun. This is a bit hard to visualize in your mind, but when it’s spinning, so when it’s sunny, but what is it summer solstice, it means that the hemisphere that that summer solstice is literally like the pole is facing the sun, because it’s on its side and it will do that for a quarter of its journey. So like 24 years it will be or 21 years, i can’t remember it will be facing the Sun so and then as it comes comes around the other pole will face the sun and the other one will be in complete darkness for for 20 or so years.

Chris
Wow.

Naomi Rowe-Gurney
Extreme but in a different way.

Alfredo
Oh my god like that will definitely mess up whatever atmosphere… Good luck in trying to understand what’s going on…

Naomi Rowe-Gurney
Who I feel sorry for the people that have to study the magnetic field because because it’s on its side as it’s rotating. The magnetic field like pops out the back like a corkscrew. So, looks like a normal bar magnet, you know, like, it’s in like a little cone shape that comes out out of the back away from the sun, whereas Uranus would be like literally a corkscrew coming out from. So good luck to them studying that.

Alfredo
Oh my god, that is fascinating.

Chris
How come How come Uranus is tilted?

Naomi Rowe-Gurney
We don’t know.

Alfredo
I think that there was a suggestion of giant impact.

Naomi Rowe-Gurney
There are a few suggestions. But yeah, the giant impact one is a popular one because it’s easy to kind of visualize, but I’ve heard a lot of counter arguments that say that it hasn’t. Like the after effects would have been different if it had been a giant impact. But obviously there’s no there’s no way to find out. There’s no way to apart from to study the planet more. But another thing that’s weird about Uranus is that it’s cold. It’s actually got a colder atmosphere than Neptune. Even though Neptune’s further out than Uranus. So should technically you should just get colder as you go further away from the sun. But Uranu’s atmosphere is actually the coldest in the solar system. So yeah, so that’s another thing that kind of compounds the big Impact Theory because if it impacted Uranus then all of its heat would get lost. So kind of turn the planet inside out. This impact. So it is a compelling theory but there are other ones as well.

Chris
I love that! I love that there’s a giant mystery just there

Naomi Rowe-Gurney
They’re looking though.

Chris
My final big question: the conditions on Neptune and Uranus with them being ice giants, and this is one that you can answer as well, because this is going to be talking about exoplanets.

Alfredo
Uh-uh.

Chris
Are the exoplanets or are they known exoplanets with similar conditions to our two giants? Or do they think there are?

Naomi Rowe-Gurney
Yes. There are a lot. It’s one of like the major, like scientific motivators for studying ice giants. Unfortunately, I feel like it should be the other way around. Because the ice giants are like super important to understand anyway. But a lot of people like to look at exoplanets because.. they could have life on them I suppose. They are kind of, you know, exotic and fun. I’ve never been really interested in exoplanets because I can’t see them. They just points of light… although saying that that my data from Spitzer is just a point of light, but you know, I can see if I want to in a different telescope.

Alfredo
That is… that is a fair description, but I would, I was about to be devil’s advocate on that, because some of the exoplanets that we’ve been able to observe directly, I think they are really far out so they are on the ice giant scale, but I think they’re all quite massive like Jupiter or bigger size so maybe not exactly like

Naomi Rowe-Gurney
There are quite a few that they call Neptunes or Neptune-like planets even though that Neptune and Uranus like but because we think that Uranus is weird and probably didn’t start out that way. And Neptune is kind of the quintessential ice-giant. They’re called Neptune, like, exoplanet so there are a lot it’s actually I think because of like observational bias. They’re one of the most common types of exoplanets that we have observed because they’re at that kind of Goldilocks mass that that you can observe very easily with certain methods.

Alfredo
I’m glad that we’re getting a definite answer in the sense that Neptune is just common. And it’s just like every system has a Neptune while we got a Uranus!

Naomi Rowe-Gurney
Exactly that’s why I like Uranus the best! Everybody always asked me “What’s your favorite ice giant?” and it used to be Neptune because I prefer the color that was literally it. It was completely be superficial. But now I think it’s Uranus, because it’s kind of the oddball, you know.

Alfredo
It does its own thing.

Naomi Rowe-Gurney
I like him, just the way he is!

Chris
It absolutely sounds like one of the most interesting planets in the solar system.

Alfredo
Absolutely.

Chris
I have no idea about all of this stuff.

Alfredo
And it’s chill. It’s laying on its side with unpretentious

Naomi Rowe-Gurney
It’s relaxing!

Chris
Just having a rest. Paint me like one of your French planets.

Alfredo
You have taugh us a lot about ice giants a lot about Uranus

Chris
really been mind blowing for me a lot of this stuff is fascinating. Cool. Thank you so much for joining us today.

Alfredo
Yeah, thank you so much.

Naomi Rowe-Gurney
Thank you for having me!

Alfredo
If you want to say where people can find you online if you want or anything?

Naomi Rowe-Gurney
Yes. You can find me my science Twitter which is @NRoweGurney. And that’s pretty much all the social media that I do. I don’t I don’t do any of these newfangled things like Tik Tok or even Instagram. I’m rubbish at so you know, Just twitter. That will do.

Alfredo
Thank you so much for joining us and it was an absolute pleasure.

Naomi Rowe-Gurney
Thank you for having me.