The Energetic Cat - EWTS #009

Joe: Hello, and welcome to Enough with the Science, Season 2.

Senan: Yes indeed, we're back after a summer of freedom and frolicking.

Joe: Yes, I'm Joe.

Senan: And I'm Senan, and this week we're going to start off Season 2 with a conundrum that has been keeping Joe awake at night.

Joe: Well, now, before we go into that, just to let you know that if you're new to the podcast...

Senan: Are you going to waste a minute of every podcast by telling people why we're here?

Joe: Yes, absolutely. This is somebody's first time. They're switching on to us for the first time and going, "What is this about? Why would I listen to this for the next 20 minutes?"

Senan: Okay, let me short-circuit this. This podcast is Nerd versus Joker.

Joe: It's like a Marvel comic that's gone wrong on air. So basically, Senan is the nerd and I try and derail his nerdness.

Senan: So what is it that's been keeping you awake at night, Joe?

Joe: Basically, it's a simple question. I can't understand... there's two ideas in my head that I just can't mesh together. Now, this happens to me many times, but I don't often have the opportunity to let Senan enlighten me and let me get some sleep. So, the two ideas are: the Law of Conservation of Energy, so that energy cannot be created or destroyed, it can only be converted from one form into another, versus the slow, inexorable death of the universe, where eventually everything just blinks out and everything is cold and dark and there's nothing left.

Senan: So you mean some kind of generic death or is there a specific kind of death of the universe you have in mind?

Joe: Eventually the last final star winks out.

Senan: So, might the term "heat death" apply to what you're trying to convey?

Joe: I wish I'd used that as a band name at some stage! But I had never heard it until you brought it up. So maybe that is the official term for what I'm describing.

Senan: I think there is the theory, yeah, that the universe will eventually... Now we're talking about, it's estimated, trillions upon trillions of years from now that the universe will eventually undergo something called heat death. Implicit, I think, in your question is the idea that in order for that to happen, all the energy in the universe has to somehow disappear.

Joe: Well, yeah. If you look at energy, like it's heat, it's light, you can see it, you can feel it, it does stuff. And then if there's nothing but a cold, dark, black, dead universe—and I hope you're not tuning in to be cheered up this week—but if that's all that's left, then where is the energy gone? There. That's what keeps me up at night.

Senan: Okie doke. Right, I'm going to give you the answer first and then we're going to delve into the details. [laughter]

Joe: The answer is I have the wrong end of the stick completely.

Senan: The answer is that the energy which currently is ordered in a particular way, all of it will become disordered. So, all of the energy will still exist, but it'll all be disordered.

Joe: Entropy. I love it.

Senan: Entropy is exactly what you're talking about. So another term for the heat death of the universe is maximum entropy.

Joe: Maximum entropy?

Senan: Yes. So entropy just in this context just means disorder of energy.

Joe: So essentially, entropy means that in the way our universe is ordered at the minute, that it kind of goes from order to disorder. Energy moves from a situation...

Senan: Yeah. And that is the kernel of what's causing, or will cause, the heat death of the universe eventually. But we need to first of all talk about what the hell is energy anyway. Now, the fact is energy is not a thing at all. Everybody has been taught in school about conservation of energy and this kind of energy and that kind of energy. Energy as a thing, as one single thing, just doesn't exist. It's a nice little human invention. It's an abstract concept we've invented to describe lots of different things. And what they all have in common is that we can get some kind of work out of them. We can piggyback on these phenomena of loads of different kinds and we can get some kind of work out of them.

Joe: Some kind of work out of them?

Senan: The potential to do work for us.

Joe: It's a kind of selfish way of looking at energy. You have to work for us. If you don't work for us, you're not energy.

Senan: And that's yet another definition of the heat death of the universe is when the universe's ability to do any work expires, that's the heat death of the universe.

Joe: Okay. I think you're going to maybe have to define work. What's work?

Senan: Yeah, we'll come to that. I want to talk about the disordered part first. So another way of describing it is disordered energy. In other words, when the entire universe is just composed of disordered energy, that's also the heat death. What do I mean by disordered? So I'm going to give you a little analogy, which is probably going to break down pretty quickly with one or two questions from you, but let's dive in.

Joe: Here we go, I'm ready.

Senan: I want you to imagine you've got a little jam jar. And it's empty, you've washed all the dregs of the jam out of it. And you've three small piles that are not touching each other in the bottom of the jam jar. One of them is sugar, one is salt, and one is pepper. Three little discrete little piles. You put the lid on the jam jar and you shake the hell out of it. And then you put it back down on the table. And what you had was three piles of ordered energy. And what you now have is one big pile of disordered energy. The work of making your food sweet, you can't use it for that purpose because if you put a spoonful in, you're also going to get salt and pepper taste, and vice versa. So that's an analogy of the difference between ordered and disordered energy in that you no longer can get useful work out of that.

Joe: Just to be really mean. So disordered energy we can't get any work out of.

Senan: Yeah.

Joe: So then it's not energy.

Senan: No, it's energy in that it is capable of creating activity on the microscopic level, but the activity is so random and so multi-directional that there's no coherent direction to it. So, say the flow of a river. The water in a river, it's all flowing in one direction, so that has a coherent energy flow in it. It's kinetic energy, the movement of the water, and we can make use of that with a generator that we put, or a water wheel or whatever, into the river. So that's a coherent energy. It's all flowing in one direction. And we are basically going to piggyback on that flow to generate electricity, for example.

Joe: Okay. So the light of the sun.

Senan: Yeah, the light of the sun is energy that is coming down that we can make use of. So that's orderly energy, like the flow of the river. Now let's talk about disordered energy. I gave you one analogy there, the jam jar a minute ago. Another one is a room which is completely sealed. Imagine a room with no doors, why would somebody build that? Anyway, let's assume that there is a room which is completely sealed and the air in the room is all at the same temperature and the walls of the room are at the same temperature. Okay? So there's no energy flow going on anywhere there. So you don't have a situation where one side of the room is hot and the other side is cold and the heat is trying to flow across to make up the difference. That energy... so there's still plenty of energy in that room in that if you look at the molecules of air down at the microscopic level, they're all bouncing around like molecules always do. But they're doing it all in random directions. There's no coherent direction to it.

Joe: Has anybody built this room? Has anybody ever done this as an experiment? Trying to build this Schrödinger's air?

Senan: Well, if there was a cat in there, there would be of course some energy.

Joe: You could have done Schrödinger's elephant?

Senan: Well, I suppose it's just easier to pick up the cat, isn't it?

Joe: And nobody cares about cats. Oh, that's it, we're cancelled. Cancelled already. First episode in the second season.

Senan: So the room is kind of a bit of an analogy for the universe when it undergoes heat death in that all these molecules are still there with their own little discrete packet of energy, but they're all moving around in different directions and it evens out to be one homogeneous mass that has no particular coherence. It's all disordered.

Joe: Okay. So energy has to be coherent to be energy. If it's not coherent, then it's not...

Senan: Well, to be energy that we want to make use of, yes.

Senan: That's a very interesting idea, coherent. We mentioned the river of course, that's one example. Another example is a boulder hanging out of a crane. So a boulder is 20 feet up in the air and suspended from a rope that's connected to a crane. Obviously it's not moving, but it has a lot of potential energy just by sitting there. And all that potential energy is focused towards the ground, towards the earth underneath it, because gravity from the earth is pulling against it. So again, even though it's not moving, it has this coherent potential energy focused towards the ground.

Joe: To land on, for example, a cat.

Senan: Potentially, yeah. It might make a cat burger if it hits just right.

Senan: So we've touched on this idea of energy is only something we're interested in calling energy if we can get some work out of it in some shape or form. And then we've got to talk about energy gradients. So that's a bit of a complex abstract topic.

Joe: I'm going to come back in about half an hour, will you just talk away?

Senan: So tell me, actually before we go any further, what's your concept of a gradient?

Joe: A gradient is like up a hill. There's a hill. There's a gradient when you were trying to go up a hill in the car in the ice. And there's a gradient up the hill depending on the gradient of the hill and how good your tires are, that will dictate how long it will take you to get up the hill. So there's a kind of connection between them.

Senan: Yeah. So would you say it's like the angle of the slope?

Joe: Well, maybe that's the definition, yes. I wouldn't disagree with that, Your Honor. I'm just going to consult with my client.

Senan: So imagine a ball sitting on top of that hill. And there's like a bit of a rock holding it, stopping it from rolling down the hill. There's an energy gradient there.

Joe: We're very boulder-centric today. We're having a very boulder, rock-centric podcast. Rock, paper, scissors.

Senan: So the ball is there, but it can't roll away because something is in the way. But it's on top of the hill. So there's an energy gradient there. It just is a coincidence that the hill also happens to have a gradient called a slope. But essentially that ball is like the boulder swinging out of the crane. It's got potential energy to go down the hill.

Senan: But anyway, let's try and define what I'm talking about as an energy gradient because it's a key part of this concept of something we can exploit to get work out of it. So essentially, if we think of a situation where we have two bunches of stuff; we're getting into the real technical language now.

Joe: Okay. Two bunches of stuff.

Senan: And those two bunches of stuff might be side by side, or if they're not, they're somehow connected with each other. Okay? But we look at the side-by-side example first. If you've got a balloon, and you blow it up, and then you hold the nozzle with your fingers. So inside that balloon, you've got a load of high-pressure air that you blew into it. And then around the outside of the balloon in the atmosphere around us, you have air, but it's at a much lower pressure. So there's a gradient there. There's a difference between the high pressure in the balloon and the low pressure outside. And currently you have blocked the passage, the pathway that would allow the higher pressure part to flow into the lower pressure part because the gradient wants to equalize itself. The gradient wants to naturally go away.

Joe: Okay, so the nature of gradients are to disappear.

Senan: To gradually... some fast, some slow, to disappear. So let's say you take a little propeller thing and you attach it to the nozzle of the balloon. And then you release the nozzle of the balloon. All the high-pressure air will flow out to equalize with the low-pressure air outside. And along the way, it'll spin that little propeller and maybe generate a little piece of electricity for you. So that's essentially what a gradient is. We used high pressure as an example, but we could have used other ones, say chemical energy like a battery. So in a battery, you've got on one side of the battery, you've got a load of free electrons. And on the other side, you've got a load of positively charged protons. So that's the negative and the positive terminal. Normally they're not connected to each other, but you introduce an electric circuit, i.e., maybe you connect a torch to the battery or your mobile phone or something, and now they can flow. So although the two bunches of stuff; that is, the negative part of the battery and the positive part; are not actually beside each other in the same way that the air in the balloon was, as soon as you make a circuit from the negative to the positive side, you're making a connection between those two areas and that's allowing the flow. The gradient wants to even itself out, i.e., flatten the battery.

Joe: So gradient, you could use just a difference in concentration?

Senan: Yeah, a difference that wants to resolve itself, a difference that wants to flow so that the difference goes away.

Joe: Yeah. So essentially there's either more of one in one place and less of one in another place. And the stuff wants to go to where less is.

Senan: Yes, essentially, yeah. And we piggyback on that in various ways to get work out of it.

Joe: Okay.

Senan: I mean, did I mention this already? The engine of a car. You've got a little explosion takes place inside in the cylinder. And suddenly you've got the explosion produces a pile of high-pressure gas. But outside the cylinder, the gas is at a much lower pressure. So the high-pressure gas inside pushes the piston down in its attempt to get out, to get back out to get rid of that gradient. It pushes the piston down, which turns the engine for us and we get work out of it.

Joe: Yeah, you did say that already.

Senan: Yeah, okay. Well, now...

Joe: I don't know, I wasn't listening.

Senan: Now it's been doubly reinforced.

Joe: Okay. So a gradient essentially, there's a difference in... I want to say concentration, but maybe that's not the right word, but that it wants to flow from there's a lot of something over here and there's not so much over here and it wants to equalize.

Senan: Yes. Pretty much, yeah. That's as good a description as you're going to get.

Joe: We're in trouble if that's as good as we're going to get. We are in real trouble. As a science podcast.

Senan: So the universe is absolutely chock full of gradients. So every star, every sun, every black hole, all of the energetic stuff that's happening around those celestial bodies is all down to a gradient. Like there's a massive gradient between the heat and pressure in the middle of our sun and the surrounding space, which doesn't have anything like the same amount of heat or pressure. So that's why all this energy is streaming out of the sun. It's trying to resolve that gradient. It's trying to flatten that gradient.

Joe: So when all those gradients in the universe are gone...

Senan: That's the heat death.

Joe: That's the happy thought. We should have some sad music. Okay. So when all those gradients are gone. So the energy isn't gone?

Senan: No.

Joe: Just the difference between the energy gradients? The pockets of stuff?

Senan: Yeah. The pockets of stuff are gone, yeah.

Joe: But the energy is still... but it's not energy because we can't make it work.

Senan: It's not energy by our definition, but it's still energy at a nano-scale level or molecular level. Those molecules are still vibrating the way they've always done, but now none of them are coherent. None of them are all going in the same direction.

Joe: But then is there not the possibility that it'll spark off again?

Senan: So, there are some wild theories about the potential for the universe recycling itself.

Joe: Okay.

Senan: But they're wild and very, very speculative. But there is at a local level, of course, we are able to reverse gradients. I mean, you can recharge the battery in your mobile phone every day. So that's an example of a gradient being reversed. In other words, you're recreating the gradient that gradually ran down during the day as your phone battery ran down to zero.

Joe: Right.

Senan: And you might then start to ask me, "Well, can't we just reverse all the gradients in a similar way and stop the heat death of the universe from happening?"

Joe: But do you see... Why would we want to do that? It's my question.

Senan: Well...

Joe: The way the world is going... Heat death of the universe... best we can hope for!

Senan: Maybe we want to accelerate it.

Joe: We're going to recycle the universe! No!

Senan: The thing about reversing a gradient is you have to use another gradient to do it.

Joe: Aha.

Senan: So the electricity that you use to recharge your phone battery is coming from a generator somewhere which is piggybacking on another gradient to generate that electricity. So you're just shifting the gradients around.

Joe: So if you don't have any gradients, you can't fix the gradients. Once all the gradients are gone...

Senan: Yeah. Plus there's another problem. All these processes that we use to piggyback on one gradient to get work out of it, they're all imperfect. In other words, we don't get all of the energy into a usable form. So say that generator that's generating the electricity is from a hydroelectric scheme. Some of the energy of that water that's flowing through the propeller is going to be lost to friction in the ball bearings that the propeller shaft is spinning on, to viscosity in the water, to various things like that. So what's happening there is that a small amount of the energy is becoming disordered and useless to us at that point. And every time we make use of a gradient for some purpose to do some work, small amounts of the energy are not correctly converted to the work we want and they end up being disordered energy that's of no use to us anymore.

Joe: Ever.

Senan: Ever. In all likelihood, ever. With the result that that leakage—I don't like using the word leakage because it suggests that the energy is going away somewhere. It's not going away. It's just becoming disordered. But that leakage gradually accumulates over time. So even though we might... like obviously we humans don't have the technology or the scope to reverse all the gradients in the universe. But let's say we were super-aliens who could do that. It still would only delay the heat death of the universe because every time we reverse one of those gradients, we're actually losing a little bit of the energy. It's leaking away into a disordered state.

Joe: And just as far as the happy thought of the heat death of the universe goes, is that the sort of accepted inevitable end of everything?

Senan: Well, it's probably the most accepted theory about how the universe will end. I mean, look, we're just smart monkeys. We don't understand everything.

Joe: Speak for yourself.

Senan: But it's an interesting point you raise because, you know, if we look at it philosophically, we are a component of the universe. So by us having this discussion and scientists having these thoughts, it's the universe contemplating its own demise. Which is a pretty amazing thing that the universe has developed sufficient intelligence to be able to actually become aware of the prospect of its own demise and maybe look for ways to avoid it or delay it.

Joe: Yeah. Well, it just frightens me that we could be considered the intelligence of the universe. Surely it could do better.

Senan: Well, one or two of us anyway.

Joe: Surely at this point, it could do better. It's got trillions of years. Maybe it'll figure it out. But I do think, the first thing that would occur to me is that the heat death of the universe is just all of this disordered energy.

Senan: Yeah.

Joe: If there was a way to reorder it... like it's still there. I mean, it's not energy, whatever you want to call it, it's not doing any work. But I mean all the molecules are kind of dancing around the place and kind of going, "Okay, I'm doing my own thing at the minute." But if it ever decided to kind of head...

Senan: So maybe the infinite number of monkeys with the infinite number of typewriters who theoretically could come up with the works of Shakespeare if you give them enough time. I mean, maybe the random motion of the molecules in the universe would eventually line up.

Joe: Yeah. If they're all equally random.

Senan: But I think the monkeys are more likely to make Shakespeare than for that to happen.

Joe: Leaving aside the fact that Shakespeare was, I suppose, an advanced monkey.

Senan: Well, that's all we can ever hope to be, advanced monkeys.

Senan: So now, you think you've got a good understanding of it all?

Joe: No, I don't. I actually don't because I still... if I see a cold dead universe... I suppose, of course, being human, we think we should be able to perceive energy. It should be able to see it, should feel it. It's got to be light, it's got to be heat, it's got to be explosions, it's got to be stuff. But at the end of the universe when there's just nothing. Nothing that... like there's no noise. That background noise that you hear in all the space movies, that's not there. There's no... just silent blackness in all directions forever.

Senan: Yep.

Joe: And yet all of those little molecules are still sitting there going...

Senan: Yep.

Joe: What a waste.

Senan: Well, is this what they went to school for? You know, is this like... we worked really hard to become these molecules?

Joe: Well it wouldn't be molecules even, it'd only be... it would be subatomic stuff I imagine, is it? Or would it actually be molecules?

Senan: Good question. I don't know whether the molecules would break down themselves. Whether the entropy, you know, when the maximum state of entropy is reached, does that mean the molecules no longer have the ability to hold themselves together? I don't know.

Joe: Yeah.

Senan: But yeah, it's an intriguing thought that maybe it would actually devolve into the subatomic building blocks of the universe, the quarks and gluons and all the rest of it.

Joe: And then there's so many of them in so much space. Surely two of them just pop together into a new universe.

Senan: Well that's probably what the Big Bang was.

Joe: This has all happened before. Have we made this podcast before?

Senan: But anyway, I'm going to throw a major spanner in the works now.

Joe: Oh god. I was just getting my head around it.

Senan: There is another form of energy that doesn't behave like I've just described for the last 20 minutes.

Joe: Of course. Of course there is.

Senan: At least it's a form of energy that we think exists.

Joe: Aha.

Senan: We've never detected it. We can only infer that it exists. And it's what's called dark energy.

Joe: So we infer it from...

Senan: From the fact that the universe is expanding and its expansion is accelerating.

Joe: Okay.

Senan: So there's some invisible force that we can't detect which is causing... we can see the far-off stars and galaxies, we can see that they're getting further away from us all the time. And the rate at which they're getting further away from us is getting faster and faster all the time.

Joe: But this always blows my mind. So they're getting... they're all moving away from the center of the universe? Or they're all moving away from us?

Senan: From each other also.

Joe: Yeah.

Senan: Space, all space is expanding. So for example, leaving aside the fact that the moon is eventually going to depart from Earth's orbit, but let's assume it never did. It would still gradually get further away purely due to the expansion of space. In other words, the amount of space between us and the moon would get larger because the individual pieces of space are getting bigger.

Joe: But can we measure that or are we all... like, am I getting bigger?

Senan: I tell you what, you're doing a good job with the skin regimen there because the wrinkles don't look one bit like one and a half million years ago.

Joe: Like, so when I was born, was I like two inches tall and now I'm like kind of 50 feet tall? I mean, what do we know? It's not on that scale. But is it relative? Are we all relatively getting bigger?

Senan: Oh yeah, you mean are we all getting bigger at the same rate due to the expansion of the universe? Yes, we probably are. But it's such a slow rate on our scales, on the scale of a human being or even on the scale of planet Earth, the expansion is so slow that we can't perceive it. But when you look over vast distances to galaxies and stars that are very far away, then you can measure it because of the amount of space between us and them.

Joe: But it's not just that there's all of these clumps of matter and energy and the space in between that clump of matter and energy and the next clump of matter and energy is getting bigger. The actual clump of matter and energy is also expanding.

Senan: Yes. The entire fabric, everything is getting bigger.

Joe: But we could have no real idea whether it was just sort of expanding and contracting or doing whatever it was. It could be bigger and smaller and elasticated...

Senan: That is yet another one of those way-out theories that potentially a point will come where it'll all just reverse and start coming in again. But you know, is it going to happen? Who knows?

Senan: So you're going to have a situation where the amount of energy that's currently contained in say one cubic meter of space, in maybe a trillion years from now, that same amount of energy might now be contained in two cubic meters of space because of this expansion. So the energy is effectively getting diluted a bit by that expansion.

Joe: But if there was a gradient right between that cubic meter of energy and the cubic meter of energy that's next to it, when they both expand to two cubic meters, surely the gradient would be the same?

Senan: Probably not locally. In other words, in one point.

Joe: Ah, okay. Yes, because they've moved.

Senan: So if you were to measure it across the full width of the two cubic meters, maybe it would add up to the same as it was originally.

Joe: Yeah. Okay. So as a whole it would be, but in each individual point it wouldn't be because they've moved.

Senan: Yeah. So that effect, that expansion effect is also helping to bring us towards the heat death of the universe a bit faster than we otherwise would. And the weird thing about dark energy, as best as we can calculate based on advanced mathematics that I don't understand, is that it doesn't undergo the same entropy or dilution. In other words, the cubic meter of space now, the amount of dark energy that's in that now versus what will be still a cubic meter, not the two cubic meters in a trillion years time, will still have the same amount... in other words, the dark energy part won't have been diluted in the same way that all the other energy is. It's really mind-bending stuff.

Senan: You're about to ask me how does that work? Nobody knows. It's just based on the mathematics. So they observe the movement of the celestial bodies and calculate the speed of acceleration of the expansion. And from that they can work out the forces involved with dark energy. And from that they can work out, "Is dark energy diluting gradually as the universe expands?" And it's not.

Joe: So that means dark energy is replicating itself?

Senan: We don't know. We don't know. We understand so little about the mechanism behind the expansion of the universe. I mean, dark energy itself is not something we've ever detected. We're only inferring that it probably exists.

Joe: Well, we're actually just making it up to explain something that we have observed. So let's say it's like what's that word they use? Homunculus?

Senan: Homunculus.

Joe: The little man in your brain that people used to attribute to people's actions.

Senan: Yes, somebody in your brain or in your body doing things. He's usually very quiet in my head except after a night's drinking when he starts playing the drums.

Joe: Well, yeah, they can be annoying like that. But you know, it might seem that this is a very depressing episode of Enough with the Science.

Senan: I was just about to make that point. It's like a newborn baby worrying about the provision for his old age care. You know, I mean...

Joe: Although every newborn baby right now should be thinking about that. Get a pension. Sign in. Get a pension right now. The way the world is going.

Senan: So here's one more little philosophical conundrum I can leave you with.

Joe: Okay. Just in terms of the dark energy.

Senan: Yeah.

Joe: So we can't talk about gradients or... we have no idea about...

Senan: We don't think it has any useful gradients. It seems to push equally in all directions, which sounds like it might be a useful gradient, but because everything is pushing equally in all directions, the net effect seems to be no gradient.

Joe: Right. Okay.

Senan: So here's a question for you we'll leave as our parting shot.

Joe: Okay.

Senan: If all work and activity effectively ceases with the heat death of the universe, does that mean time has stopped as well?

Joe: Ooh.

Senan: Because there's a theory that the universe's tendency to go from a state of very little entropy towards maximum entropy is effectively what is the passing of time.

Joe: So the definition of time is that like you go from a state of order to disorder.

Senan: Yes.

Joe: And that flow is time.

Senan: Now, that's not a standard definition that everybody recognizes, but it's a theory. And it's an interesting question. So when entropy doesn't get any worse because it's gotten as bad as it can get, does that mean time is finished?

Joe: I would imagine that in the countless trillions of years until the heat death of the universe, that really would become the definition of an academic question. I think the practical application of that question is... I don't know if there's something which is zero but concentrated. Maybe dark zero.

Senan: Well, it would be handy. Say you've got a deadline for a project or an essay that you've got to deliver and you're running out of time. If you could zip forward to the heat death of the universe, you'd have unending time to finish your essay.

Joe: Or no time. Time would be gone. There is no time. There'd be less time, surely if we went fast forward to the end of it.

Senan: Is no time the same as less... I don't know.

Joe: Is no time the same as lots of time? I don't know.

Senan: Okay, well it's probably enough time anyway for Enough with the Science this week.

Joe: Okay. Well, look, just have lots of fun before the heat death of the universe. That's, I mean, our parting shot has to be that there's lots of things that you can do in the trillions and trillions and trillions of years before maximum entropy ensues.

Senan: Live your life. Have the craic, as we say in this part of the world.

Joe: Absolutely. Listen to our first season of podcasts.

Senan: And whatever else you do, make sure you subscribe and like our podcast.

Joe: Oh yeah. Absolutely. And hopefully we'll catch you next time. I'm Joe.

Senan: And I'm Senan. All the best now.

Joe: Take it easy.