Tom and the flying sofa: Part 2: The Surprising World

Author and copyright: E.P. Visscher

Flying again

What was that sound? Was it the engine? There it was again, this low, rumbling noise. The flying sofa was trembling and losing speed, and suddenly I could feel my heart beating and my hands shaking. This is not going to end well, I thought, and tried to pull the sofa up by jerking the stick towards me. Unfortunately, that didn’t help at all, and the sofa was hurtling faster and faster to the ground. A few hundred yards from impact, I suddenly felt a strong pull. The sofa was going up and down, turning left and right, but once the chaos subsided, I felt we were descending much more slowly than before. Relieved and excited I looked up, and was pleased to see that I’d somehow managed to press the right button, because our parachute had opened beautifully. The sofa was slowly winding its way down now, giving me time to realize that I’d forgotten to charge the engine’s batteries overnight! I promised myself to be a bit more careful in the future, as there were too many things that I still wanted to see and do…. Luckily the winds weren’t very strong, and our final landing spot wasn’t too far from Grandpa’s place. The landing itself was a bit bumpy, but I survived with only a few scratches, and decided it was time to head home for a break. Grandpa wasn’t up yet, so I went back to my room and collapsed on my bed.

That’s when I remembered how my day had begun. I’d woken up early; excited about the adventures to come. The flying sofa had been waiting for me since my last visit, and she looked better equipped than ever. I had quickly started her up and steered her through my open window. The weather was beautiful and the sofa carried me higher and higher. A few large clouds floated above me like snow-covered mountains. Below I could see Grandpa’s house and his vegetable garden; the same garden in which Zara, the hare, had eaten so much cabbage a few months earlier. The nearby orchard still looked the same too, except for the blossoms, which had finally given way to bright, red apples. I remembered Nana and Kiri, the geese, who I’d met among the fruit trees. They didn’t seem to be there today, but perhaps I’d meet them in the air somewhere! As I was flying around the forest and meadows near Grandpa’s place, I remembered all the other characters I’d met last time: the exotic tree stump, which sadly had been cut down; the wise worm, with its hidden, underground ways; the brave herons, who leapt off branches like pros on their very first flights, the….

Suddenly I was pulled back into the present by something hairy that jumped onto my bed. ‘Hello, Tom!’ the cat meowed. ‘Hi, Kit!’ I said. ‘How are you?’ ‘I’m fine, Tom,’ she said. ‘Just a bit tired from last night, so I thought I’d join you here on the bed.’ ‘Please do!’ I said. ‘I was just thinking about you and everybody else I met last time I was here.’ ‘Did you have a good time then?’ Kit meowed. ‘Yes, it was great!’ I said. ‘I met so many interesting characters; each one of them had an amazing story to tell, and they were all so different! ‘Really?’ Kit said. ‘Yes,’ I continued, ‘it was fascinating to discover that every animal has its own way of living; its own way of seeing things.’ ‘So what did you learn about me?’ Kit asked. ‘I learnt that cats do exactly what they feel like; they follow their dreams and don’t worry too much about what other cats or humans think.’ ‘You might be right!’ Kit meowed. ‘I definitely don’t like to be told what to do; I can only be persuaded, and then only with plenty of love and attention!’ ‘Hmm … thank you for that piece of information!’ I laughed while rubbing Kit under her chin. ‘That feels very good,’ Kit purred, cuddling up beside me. ‘Don’t worry,’ I said, ‘I’ll be cuddling you a lot this morning, especially if that will persuade you to join me on the sofa again!’ ‘You’re making it very hard for me to say no,’ Kit meowed, ‘but I really don’t want to get attacked by herons again!’ ‘Well, I was planning a completely different adventure anyway,’ I explained, ‘and I’d love for you to be a part of it!’ ‘Let me dream about it,’ Kit purred, and together we drifted off to sleep.

In my dream, Kit and I were flying again. I wanted to see if I could reach the end of the sky, so I pushed the sofa to its limits, making her climb higher and higher. The clouds were far below us now and looked like they could catch us if we crashed. I wished it were possible to roll around in them and bounce from one cloud to another…. A few minutes later, the sky ahead looked darker than I’d ever seen it before, and the Earth was quickly disappearing out of sight. When Kit realized how far we’d traveled, she shrieked and asked me to go back. I happily complied and enjoyed myself immensely on our way down. To see the oceans, mountains, forests and deserts from such a distance was amazing. ‘The Earth is so beautiful!’ I shouted to myself as we raced around the globe. ‘We’re going to crash if you’re not careful!!!’ Kit meowed anxiously. ‘Don’t worry, Kit,’ I cheered, ‘the clouds will catch us!’ Passing through the white and hazy vapours, I realized we weren’t slowing down at all, so I quickly tried to open the parachute, but it was too late…. For a moment I was convinced that we’d died, but somehow the Earth had opened up below us, and we were racing down a dark, hot tunnel, going deeper and deeper into the planet’s core. Just when I thought I couldn’t stand the heat anymore, I woke up, and slowly realized I was still alive. I felt relieved but also a bit anxious; Grandpa should really check that parachute once more….

Just when I’d had that thought, I heard his voice traveling up the stairs: ‘Breakfast’s ready!’ ‘Thanks, Grandpa! Kit and I will be down soon!’ I shouted back. ‘Ah, yes, the cat,’ Grandpa said. ‘I need to put her nappy on. Would you like to learn how to do that?’ ‘Why not?’ I said. ‘But don’t you need to empty her bladder first?’ ‘You’re right, Tom, I almost forgot. You see, I didn’t sleep too well last night; I had this awful dream about the flying sofa; we need to make sure she’s absolutely safe to travel with today.’ I nodded while Grandpa took Kit in his arms and positioned her above the sink. ‘I’ve had to empty her bladder like this ever since she had the car accident,’ Grandpa explained. ‘Kit doesn’t enjoy it, but she knows that it allows her to carry on doing the things she likes.’ ‘It doesn’t smell great though!’ I said. ‘But it’s worth it,’ Grandpa smiled while stroking Kit’s back. ‘Yes indeed!’ Kit meowed. ‘Alright then,’ Grandpa said, ‘let me show you how to put her nappy on; it might come in handy one day!’

After we’d finished with the nappy we all looked forward to breakfast. Kit enjoyed her special cat food, and Grandpa and I sat down for some fresh bread, boiled eggs, cheese and orange juice. ‘It’s delicious!’ I said, and told Grandpa about the scary ride and daring dream I’d had earlier that morning. ‘I’m glad I told you about the parachute last night,’ Grandpa said. ‘But I wish it hadn’t been necessary for you to try it out like that! Sometimes we only remember the importance of things when we forget to look after them. I’m sure you won’t forget to charge the sofa’s batteries ever again!’ ‘I don’t think so!’ I said. ‘Well then, Grandpa continued, ‘before you’re allowed to do any more flying, we should take a look at the sofa together; I’ve tweaked quite a lot since your last visit, and some of it needs explaining.’ ‘That sounds good!’ I said with excitement. ‘I’d like to travel much higher and further this time, and maybe I’ll try out some new flying tricks, but part of me is quite scared; what if I really do crash the sofa?’ ‘It’s quite normal to be a bit scared when you’re about to do new things,’ Grandpa said. ‘You need to be daring enough to try something for the first time, like heron chicks taking their first flights, but a bit of anxiety can prevent you from risking too much at once. “Step by step” is the best way forward, I think!’ ‘Thanks, Grandpa, I’ll try to remember that!’ ‘I’m sure you will, Tom, and I’d like you to remember a few practical things as well, so let’s go and take a look at the sofa together.’

We made our way to the field where I’d landed the sofa that morning. ‘Ah,’ Grandpa said when he saw the sofa, ‘I think the first thing to do is to check if the parachute still works.’ I watched him disentangle all the ropes and check the fabric for tears. ‘It looks pretty good to me,’ he said. ‘I think we can use this one again; do you want to give me a hand with the folding?’ he asked. As we were carefully stowing the parachute away, Grandpa explained some of the changes he’d made to the sofa. ‘I don’t want you to run out of fuel too quickly,’ he said, so I decided to build solar cells into the back of the sofa. If you press this yellow button here, the batteries will charge through the solar cells.’ ‘I wish I’d known that this morning!’ I laughed. ‘Yes, that would have helped,’ Grandpa said, ‘but ideally you should have them fully charged to begin with! Anyway, you can charge the batteries whilst you’re flying by using sunlight, or – when you’re on the ground – by using electricity wherever you have an outlet available.’ ‘I’m guessing I won’t be too close to an outlet this weekend!’ I said. ‘Well, if you’re that serious about exploring the world, I better tell you about one of the other changes I’ve made,’ Grandpa said. ‘The solar cells will definitely keep your batteries charged when there’s plenty of light, but what will you do if the sky darkens and you’re far away from any outlet whatsoever?’ ‘Can’t you send a few refuelling planes?’ I joked. ‘Not a bad idea,’ Grandpa laughed, ‘but I’m afraid I’ve chosen a more practical solution; methanol fuel cells. The problem with those cells though is that they won’t last forever, because carrying extra methanol would make the sofa too heavy, so I’d use them only when the batteries run out, like this morning.’ ‘But how will I know when that happens?’ I asked him. ‘Do you see that tiny red light?’ Grandpa said. ‘That’s your warning signal. When that comes on, you should either go and land the sofa somewhere immediately, or, if that’s not possible, you can use the methanol cells to take you to a safe place.’ ‘Thanks, Grandpa! I think I’m fully prepared now!’ ‘I hope so indeed!’ ‘Don’t forget me!’ Kit meowed behind us. ‘I’m glad you’re joining me again, Kit!’ I said. ‘Let’s go and get ready!’ I raced back to the house to get my tent while Grandpa prepared some food for our journey. ‘When will I see you two again?’ he asked. ‘Tomorrow night, if that’s OK?’ I said. ‘That’s fine, Tom, but be careful, and call me when you’re in trouble.’ He helped me to secure everything on the sofa, and then it was time to leave. ‘Enjoy your new journey, Tom!’ ‘Don’t worry, Grandpa! I’m loving it already!’

In the air

‘Where are we going?’ Kit asked me after a while. ‘That’s a very good question!’ I laughed. ‘To be honest, I haven’t thought about that in too much detail! All I know is that I want to explore the world.’ ‘The whole world?’ Kit said with disbelief. ‘If I could!’ ‘But we need to start somewhere, don’t you think?’ Kit meowed. ‘Hmm, you might be right,’ I sighed, and tried to come up with a plan. ‘Would you like to go to the ocean?’ I asked Kit. ‘I have no idea,’ Kit shrugged. ‘What’s an ocean?’ ‘Just wait and see,’ I said, and steered the sofa towards the coast. The sky was still clear except for the odd cloud, and our batteries were charging nicely. About half an hour later we were flying over the water. Suddenly the air felt cool and moist, and we couldn’t see very far anymore. ‘I’m afraid it’s too misty to show you the ocean right now!’ I said. ‘You’re going to have to wait a bit longer.’ ‘That’s OK,’ Kit said. ‘I’m not too sure I want to see it anyway!’

‘Did I hear that correctly?’ a foggy voice whispered around us. ‘Is it true that you like me?’ ‘Well, I didn’t say I liked you that much!’ Kit meowed. ‘I’m almost shivering with cold!’ ‘Oh, I’m sorry,’ the fog whispered. ‘You must be one of those creatures who prefers the sun.’ ‘Yes indeed!’ Kit meowed. ‘Who wouldn’t prefer those warm rays of sunshine?’ ‘Well, you might be surprised to hear that the grasses and shrubs along the coast are very happy to see me,’ the fog explained. ‘Without me, they wouldn’t get enough water during dry summers like this.’ ‘Really?’ I said. ‘Do you hang around that often?’ ‘If you ask me personally, I have to say no,’ the fog replied. ‘Can’t you be a bit more specific?’ I asked. ‘Because that’s the vaguest answer I’ve ever heard!’ ‘Perhaps it’s the way you pose your questions!’ the fog replied. ‘I suppose you haven’t realized that tomorrow’s fog will not be “me”?’ ‘What do you mean?’ I said. ‘I’m just a random collection of tiny drops of water; when the sun rises higher and its rays start warming the air, my molecules will vibrate away from each other and travel to many different places. It’s unlikely that the exact same molecules will ever meet like this again, so “I” only exist now.’ ‘How wonderful and amazing to see you then!’ I said. ‘How long have you been around for?’ My water molecules were carried here by a parcel of warm air,’ the fog explained. ‘When we passed over the cooler air above the ocean, we lost some energy and clustered together around tiny salt crystals.’ ‘Fascinating!’ I said. ‘And will you be here all day long?’ ‘I’m afraid not,’ the mist replied. ‘Just look behind you and you’ll see what I mean.’ I turned around and watched the sun break through the mist. When I looked back at the remaining fog in front of me, a beautiful white bow had appeared. ‘That’s so beautiful!’ I cheered. ‘A sign of my ending,’ the fog whispered slowly, before evaporating into thin air.

‘Ah! Finally some sun on my fur!’ Kit meowed happily. ‘We’re glad you like us!’ a voice vibrated above us. Kit and I looked at each other with surprise. ‘Don’t tell me that that awful fog is coming back after all!’ Kit sulked. ‘I don’t think so,’ I said. ‘All I can see are some new clouds forming above us.’ ‘Can’t you see us?’ the voice continued. ‘We’ve been sent here by the sun!’ ‘Oh, but of course!’ I said. ‘We love sunshine! Please stay a bit longer!’ ‘We’re always around,’ the solar rays vibrated. ‘You just need to know where to find us.’ I steered the sofa higher through the developing clouds. ‘There you are!’ the sunshine sang when we appeared on the other side. ‘Now you can enjoy us to the fullest!’ ‘That’s very good news!’ Kit meowed. ‘When will we get to the sun?’ ‘I hadn’t thought about going that far,’ I admitted. ‘Do you really want me to take you there?’ ‘Well, I could do with a bit more warmth still!’ Kit meowed. ‘A snooze near the sun would be great!’ ‘Are you sure?’ a fiery voice resounded in the background. ‘I’m yet to meet something or someone that can stand my heat as well as I can!’ ‘Aaa…aa…are you the sun?’ I stuttered. ‘I don’t know what you mean by “sun”, but you can call me that if you wish,’ the voice continued. In essence I’m a star; a maturing star.’ ‘A star?’ I said with surprise. ‘I thought stars existed much further away, like those tiny white specks against the dark night sky.’ ‘Oh, I can see that you’ve got a long road ahead of you,’ the sun sighed. ‘If you were to be watching me from a far away place right now, I’d look like a tiny white speck myself!’ ‘Do you mean that some of those twinkling white specks I see at night are boiling hot like you?’ I said with amazement. ‘Yes indeed! Or even hotter!’ the sun spewed. ‘How hot are you then?’ Kit meowed. ‘There isn’t just one answer to that,’ the star explained, ‘but my core is the hottest.’ ‘Can we go there please?’ Kit purred. ‘You wouldn’t want to,’ the sun laughed, ‘unless you’re hydrogen gas wanting to become helium.’ ‘Is that what’s happening in your core?’ I wondered. ‘Not just that.’ the star continued. ‘When the centres of hydrogen atoms fuse together in my core, part of their mass turns into energy, and that’s what reaches you as light and heat.’ ‘You see, Kit?’ I said. ‘Why travel to the core of the sun when sunshine travels to us?’ But Kit didn’t respond, and was snoozing happily on the seat next to me.

I closed my eyes and enjoyed the warmth on my face. ‘I wish I could do this every day for the rest of my life,’ I thought to myself. ‘That shouldn’t be a problem!’ the rays sang. ‘The sun will be around for quite a while longer!’ ‘What do you mean?’ I said. ‘Well, what do you think?’ the sun radiated. ‘I thought you’d be around forever!’ I shouted. ‘Me?’ the sun repeated. ‘I’m afraid that’s not the case.’ ‘Are you sure?’ I said with desperation. ‘I only need to look at my sister stars to know what will happen to me – eventually,’ the sun sighed. ‘But I thought we could live here forever!’ I said. ‘Even if it is a bit cold in certain places….’ ‘Do you mean on that planet of yours?’ the sun asked. ‘Yes, of course!’ I replied. ‘The Earth should be a good home for you for quite a while yet,’ the sun explained. ‘But at some point, you’re going to have to move, because if you don’t, you’ll get scorched by my rays.’ ‘By the sunshine we’re enjoying right now?’ I said with disbelief. ‘I’m afraid so,’ the star continued, ‘because I’m slowly getting brighter and hotter.’ ‘How slowly?’ ‘Very slowly,’ the sun explained. ‘It will probably take about a billion years before my solar rays will evaporate the Earth’s oceans and make life on Earth impossible.’ ‘Really?’ I said, and paused for a moment. ‘If life on Earth becomes impossible, does that mean that “Life” in general will end? ‘That’s a difficult question,’ the star radiated. ‘Unfortunately I can’t help you with that one.’ ‘Well, thanks anyway,’ I said. ‘What for?’ the sun asked. ‘For making our lives possible for now,’ I said. ‘And for charging my batteries!’ ‘Oh, don’t you worry,’ the sun shone, ‘it’s what I do best. ‘And I’m sorry to have disappointed you; I really wish I’d be around forever, too, but my source of energy is limited.’ ‘Your hydrogen?’ I said. ‘Yes indeed,’ the star explained. ‘In a few billion years from now, when I run out of hydrogen in my core, I’ll switch to the hydrogen in my outer shells. But that will only be a temporary solution. Eventually my core will heat up so much that helium will fuse to carbon and oxygen. My outer layers will be released and form a massive cloud, while my inactive core remains and slowly loses its energy.’ ‘So you’ll become cold?’ ‘Ahh, yes,’ the star shivered. ‘But let’s not talk about that right now. I’ve still got plenty of hot years ahead of me.’ ‘Hot indeed!’ I said. ‘I think I might be getting sunburned!’ ‘Time to fly a bit lower then,’ the solar rays sang before hitting my skin.

I took their advice, and slowly descended through some clouds until I could recognize the ocean again. Seeing nothing but water in all directions, it seemed hard to believe that this entire body of salty liquid would one day disappear into space because of the sun’s intensifying rays. ‘Even now, the sun is a powerful force,’ a voice sighed behind me. ‘It makes us travel from one place to another – all over the world.’ ‘Who are you?’ I wondered. ‘We are the gases,’ they whispered around me. ‘Have you ever heard of nitrogen, oxygen, carbon dioxide and water vapour? That’s the air you’re flying through right now.’ ‘Wonderful!’ I said. ‘Thank you for allowing me to travel around the world!’ ‘No problem,’ the gases hissed, ‘and if you’re ever in a hurry, make sure to fly along in the direction of our flow.’ ‘Do you mean the wind?’ I asked. ‘Yes indeed,’ the air explained. ‘”Wind” is just a lot of gas moving from one place to another – fuelled by the power of the sun.’ ‘I’m starting to realize how powerful the sun is,’ I said, ‘but how does it possibly create wind???’ ‘Well, when our molecules receive energy from the sun, they absorb it and vibrate away from each other. That means that a volume of warm air contains fewer molecules of gas than the same volume of cold air.’ ‘So it will be lighter?’ I said. ‘Very good!’ the air murmured. ‘When air becomes lighter, it rises upwards, whilst elsewhere, where it cools down, it sinks downwards. The wind flows from areas of higher density to areas of lower density; it restores the difference.’ ‘I can feel that you’re blowing towards the shore right now,’ I said, ‘but when I was flying higher up in the sky, you were blowing in the other direction; towards the ocean!’ ‘Yes, our circulation is more complex than you think!’ the wind roared. ‘The shore heats up more quickly than the water, which means that the air above the land becomes lighter and warmer than the air above the ocean, so it rises. The colder, denser air from the ocean flows towards the shore, where it heats up again and rises. But, higher up in the sky, the risen air cools down and becomes denser, whereas high up in the sky above the ocean, the air cools down even more and sinks downwards, leaving space for the risen air above the shore to flow into.’ ‘Pheww, these looping airflows are getting too much for me!’ I laughed. ‘Can we change topics, please?’

‘What else would you like to know,’ the wind whistled. ‘You said you are a mixture of different gases,’ I continued. ‘Where do they come from?’ ‘They each have completely different histories and cycles,’ the wind explained. ‘Free oxygen gas wasn’t always part of the atmosphere for example. It first appeared several billion years ago, when it was released by a new kind of bacteria. The new bacteria were able to use the energy of sunlight to make sugar and oxygen from carbon dioxide and water. And these days, plants are doing the same!’ ‘So the bacteria and plants, using the energy from the sun, allow me to breathe!’ I said with amazement. ‘Isn’t it wonderful?’ the wind roared. ‘But don’t forget the carbon dioxide and water; sunlight alone isn’t enough!’ ‘You’re right,’ I laughed. ‘I’m starting to give the sun too much credit!’ ‘I think you do!’ the air swirled. ‘You seem to think that sunlight is all it takes to feel nice and warm.’ ‘Sunshine seems enough to me!’ Kit purred next to me. ‘Well, you’re both wrong then!’ the wind howled. ‘Because without water vapour and carbon dioxide in the air, the Earth would be freezing cold!’ ‘Are you serious?’ I gasped. ‘Of course!’ the wind continued. ‘The rays of the sun may heat the Earth, but all that heat would leak back into space if it weren’t for my greenhouse gases.’ ‘Greenhouse gases?’ I said. ‘Yes, the gases that keep the Earth nice and warm; like a greenhouse,’ the air said proudly. ‘I’m sorry, but you’ve lost me there!’ I admitted.

‘Ok, we’ll explain it to you,’ the gases hissed. ‘Some of us, like water vapour and carbon dioxide, can absorb part of the heat that is lost by the Earth and radiate it back into the atmosphere; keeping you nice and warm.’ ‘Thank you!’ I said. ‘I’ll try to treat you with more respect from now on!’ ‘Don’t worry!’ the greenhouse gases beamed. ‘We know that people like us a lot; they’re creating more of us all the time!’ ‘We do?’ ‘Yes, didn’t you know? Every time you burn old plant material, like coal and oil, you create more carbon dioxide.’ ‘Really?’ I said. ‘How does that happen?’ ‘Remember how plants make oxygen and sugars?’ the gases whispered. ‘They incorporate carbon dioxide, water and sunlight. When you burn dead plants, the opposite happens. Sugars and other carbon molecules react with oxygen to give carbon dioxide and water.’ ‘Amazing!’ I said. ‘Does that mean that the Earth will get warmer still?’ ‘It looks like it,’ the wind howled. ‘I can feel I’m getting stronger in certain places already!’ ‘Perhaps that’s one of the reasons why Grandpa gave me solar cells to charge my batteries!’ ‘Why, what’s wrong with a bit more warmth?’ the wind roared. ‘Oh, I’d love a bit more warmth on a cold day,’ I said, ‘but I don’t like flying through hurricanes!’ ‘That’s a shame,’ the wind sighed. ‘Because it’s a most powerful experience!’ ‘Well, I’ll leave that to you!’ I said. ‘I enjoy you most when you’re a bit more relaxed, although I wouldn’t mind an adventure every now and then!’ ‘Really?’ the air hissed. ‘Then I’ve got an idea for you. Do you see that cloud over there? I think it will soon be growing quickly and rising high into the sky. When that happens, my flows get really exciting; you’ll be going all over the place. Would you like to go for a ride?’ ‘Hmm, yes, sure,’ I said, ‘but I’ll need to get out before it rains.’ ‘Why’s that?’ the wind complained. ‘Don’t you like the fresh water I carry around with me everywhere?’ ‘For drinking, yes! And I don’t mind swimming and showering in it either, but not with my clothes on!’ ‘Ok, let’s be quick then!’ the wind roared excitedly. ‘I’ll carry you inside.’

The wind picked us up and blew us into the centre of the enormous cloud. It felt misty and moist, like the fog earlier in the day, but not as quiet and peaceful. The wind took us higher and higher, sometimes dropping us for a moment before carrying on. Kit was getting seasick and had to throw up. ‘Thank you, that’s enough!’ I shouted loudly, but the wind didn’t seem to care. The higher we got, the colder it felt. Kit was huddling beneath her pillow while I got lashed by rain, snow and hail. ‘Please, get me out of here!’ Kit meowed anxiously. I’d been trying to steer the sofa downwards, but the wind was much, much stronger than our engine. ‘I’m sorry, Kit; we need to hang on for a little bit longer!’ ‘Are you enjoying yourselves yet?’ the wind roared wildly. ‘Not anymore!’ I shouted angrily. ‘First we got wet, and now we’re starting to freeze! Look at the sofa! There’s snow and ice all over it!’ ‘Don’t you worry,’ the wind howled dangerously, ‘I’ll be done very soon….’ And sure enough, a few minutes later, the wind suddenly reversed and pulled us down again. ‘Oh no!’ I shouted when I realized how fast we were falling. ‘Do something!!!’ Kit shrieked from below her pillow. The obvious thing to do was to release our parachute, but the button I needed to press was covered with ice and snow. With my frozen hands I managed to find a knife and frantically hacked away at the lump of ice. When I finally pressed the button, we had left the cloud and were dangerously close to the water. The parachute slowed us down a bit, but not quite enough. We held onto the sofa tightly when it hit the water, and held our breaths when we disappeared below the surface. Somehow Grandpa had thought of everything, because instead of sinking further and further into the sea, the sofa bobbed back up again, and floated along like a little boat.

On the water

The sofa was gently bobbing along the waves, and Kit and I slowly got used to our new situation. ‘This is much worse than any of our previous trips together!’ Kit meowed. ‘Don’t you realize that I hate water?’ ‘I’m sorry, Kit, I didn’t want to get wet either – but look at us now!’ Kit decided to make use of the situation by licking herself clean, but her efforts didn’t last long. ‘Ewww! That’s disgusting!!!’ she shrieked. ‘Oh, yes,’ I said, ‘I forgot to tell you about the salty water….’ ‘Well, thanks very much for that!’ she meowed. ‘Just relax, Kit,’ I said. ‘The rays of the sun will make you feel better soon!’ With my feet dangling in the ocean, I watched the enormous cloud sail towards shore. Rain and hail were battering the coast, while the cloud itself was lit up by a show of fascinating lightning. A few moments later, the sun re-appeared in its wake. ‘Oh, finally!’ Kit purred. ‘Delicious, isn’t it?’ I said.

We made ourselves comfortable on the gently rocking sofa, and Kit soon drifted off to sleep. Luckily I managed to find a sandwich and some water among my gear, and I thoroughly enjoyed my late lunch – staring dreamily at the brightly reflective surface of the ocean. ‘Who knows what’s hiding below my feet,’ I thought to myself. ‘I’m glad I can’t see any of it!’ ‘I’m sure you’d enjoy yourself down here,’ the ocean splashed. ‘You’ll have so much to explore! Why don’t you join me for a dive?’ ‘Maybe a little later,’ I laughed. ‘I’m still recovering from my last one!’ ‘Oh, that was nothing,’ the water murmured. ‘You need to go much deeper if you really want to know me.’ ‘How deep should I go then?’ I wondered. ‘It depends on where you are,’ the ocean gurgled. ‘But I’d count on several miles in many places.’ ‘You must be joking!’ I laughed. ‘I might go for a swim later, but diving to the bottom of the ocean? I’d need more than a flying sofa for that!’ ‘If you think I’m too deep,’ the water splashed, ‘then wait until I get even deeper!’ ‘How would you do that?’ I said with surprise. ‘I’m not doing anything!’ the ocean lapped. ‘All I do is receive more and more fresh water from ice melting in a world warmed by increasing amounts of greenhouse gases in the air.’ ‘Is that a bad thing?’ I wondered. ‘Only you can answer that question,’ the water whooshed. ‘I don’t have any opinion about that. My levels have risen and fallen many times in the past.’ ‘What happens when your levels rise?’ I asked. ‘I’ll turn low-lying land into sea,’ the water explained. ‘I can’t help it; I need to go somewhere!’ ‘So you’d cover our islands and cities; even countries?’ I said with surprise. ‘I’m afraid so,’ the water rushed. ‘But you can’t afford to hate me, like that furry friend of yours over there.’

‘What do you mean?’ I wondered. ‘You both like to stay warm, don’t you?’ the ocean waved. ‘Yes we do!’ ‘In that case you’ll be pleased to hear that I can help you to keep warm in winter.’ ‘You can?’ I said with amazement. ‘Yes indeed,’ the water whirled. ‘In warm places and times, I can store a massive amount of heat, because I need lots of energy to warm up even a little bit. Then, when it gets colder around me, I’ll lose that heat again over time.’ ‘Like a radiator?’ I said. ‘You could say so,’ the ocean rustled. ‘My currents distribute heat energy around the world. Especially when I travel from the tropics to the poles – and back.’ ‘Wow! That sounds amazing!’ I said. ‘I’m glad you’re delivering a bit of tropical warmth to other places!’ ‘Of course the wind does her bit, too,’ the water lapped. ‘She’s one of the reasons I can travel so far in the first place, and when she’s colder than I am, I’ll heat her up when she blows over my surface, and that way my warmth reaches you as well.’ ‘Incredible!’ I said. ‘I didn’t know that you and the wind are so strongly connected!’ ‘Perhaps we’re even more connected than you think,’ the water gurgled. ‘Go on!’ I said ‘Well,’ the ocean murmured, ‘what do you think is causing the sofa to go up and down, from one wave to the next?’ ‘The wind??’ I said with surprise. ‘Very good!’ the water waved. ‘The wind creates the waves that have rocked your furry friend to sleep. But that’s not all: where do you think the wind gets a lot of her water molecules from? The molecules that cluster together when air cools, and which come down as fresh water on land when it rains? ‘From you???’ ‘You’re right again!’ the ocean roared. ‘My salt stays behind when my water evaporates, so that’s how fresh water travels from me to you.’

‘Thank you both!’ I said and took another sip from my water bottle. ‘Isn’t it time for your swim now?’ the water rushed. I looked at Kit and said: ‘Alright then; I think I can leave her alone for a while; but only if you promise me that there won’t be any sharks nearby!’ ‘The sharks around here are too small to be afraid of,’ the water splashed. ‘Come on; get your snorkelling gear on!’ I looked through my bags and found my mask, snorkel and fins. After I’d put everything on, I slowly lowered myself into the water. ‘I could do with a wetsuit too!’ I complained. ‘Just keep swimming,’ the ocean urged me on, ‘and you’ll be warm soon!’ I paddled along, and when I felt a bit more comfortable in the wavy water, I put my head down to see if I could discover anything interesting below the surface. As soon as I tried to breathe, I almost chocked on the salty water, and realized that snorkelling among the waves was far trickier than I’d thought. After a few attempts I got everything to work and started to take in my underwater surroundings. Holding onto the sofa, I was very pleased to see that the sandy bottom of the ocean was only 10 meters below me at this distance from the shore. Every now and then we passed over a rocky outcrop or an old piece of wood, so I knew we were carried along by a slow but steadily moving current. I was beginning to think that our part of the ocean was devoid of any life, when, suddenly, a half-buried ray caught my eyes. It was so well camouflaged that I only saw it when it emerged from the sand moving its wing-like fins. I’d never seen anything like it before, and for a moment I was startled.

A few minutes later, I noticed more and more rocky outcrops passing underneath us, and in several places they were vast and interconnected. Some of the rocks were almost as high as the water level, and when I looked at them more closely, they didn’t appear to be rocks at all: not with colours, shapes and structures so bright, complex and delicate. ‘Be careful! Don’t step on us!’ a voice crunched. ‘But I wasn’t!’ I protested. ‘I’ve seen you people before!’ the voice continued. ‘And I think it’s better to be safe than sorry….’ ‘What do you mean? I asked. ‘We’re alive, you see,’ the voice explained, ‘and quite fragile – unlike rocks.’ ‘But what are you then?’ I asked impatiently. ‘We are the coral reefs,’ the voice crunched. ‘Have you never seen us before?’ ‘No – never!’ I admitted. ‘I don’t even know what a coral is!’ ‘Well, what do you think we are?’ the reef asked. ‘You looked like a collection of colourful stones at first,’ I explained, ‘but then I realized that I’d never seen stones with branch-like structures before, or with complex brain-like patterns.’ ‘That’s right,’ the reef said. ‘Every one of those structures is a different kind of coral, and the reason why those corals are hard like stone is that each tiny polyp excretes calcium carbonate.’ ‘Polyp?’ ‘Yes, if you look at my corals closely enough, you’ll see many tiny openings surrounded by tentacles; each one of those openings leads to the stomach of a small creature, which is called a polyp. The structure created by many polyps together is called a coral.’ ‘Wow!’ I said as I was taking a closer look. ‘The tentacles are moving!’ ‘But of course!’ the reef danced. ‘That’s how we’re feeding ourselves!’ ‘I’m really impressed!’ I gushed. ‘I’ve never seen anything like it; you’re both stone and animal!’ ‘And plant!’ the reef added. ‘You’re kidding me!’ I laughed. ‘Not at all,’ the reef explained. ‘Some of my corals allow algae to live inside their polyps. Algae, like plants, are able to use sunlight, water and carbon dioxide to make sugars and oxygen, which the polyps use for energy. Because the algae need sunlight to do this, the corals that host them have evolved branch-like or table-like structures, catching as much light as possible.’ ‘Fascinating!’ I said. ‘Thank you very much for your wonderful stories! I think I’ll go and swim around for a while and enjoy your amazing corals!

As I was snorkelling and floating above the reef, I could see many schools of colourfully patterned fish hanging around the coral heads. The closer I got to them, the more crunching sounds I could hear. ‘Are you actually eating the reefs???’ I asked with horror. ‘Well, yes, we don’t mind a little polyp now and then!’ the parrotfish said while looking at me with one eye. ‘But don’t jump to conclusions!’ ‘Why not?’ ‘Because we can be quite helpful to the reefs as well.’ ‘Really?’ I said with surprise. ‘Yes, we enjoy eating seaweed too, which means that the reefs won’t get overgrown.’ ‘Hmm … I’ll try to believe you!’ I laughed, and let myself float on. ‘I’m surprised to see so many fish around your corals,’ I said to the reef. ‘You must get a lot of visits from fishing boats!’ ‘Fortunately not so many in this area,’ the reef danced. ‘But elsewhere it can be horrible…. Unless people are forbidden to fish – like here – they destroy everything!’ ‘You mean they don’t just catch a few fish?’ I asked. ‘A few?’ the reef choked. ‘I wish that were true! But no, often they come with huge nets, or even bombs, to catch and kill as many fish as possible. Their anchors and bombs destroy the reef itself, and so, after a few of those visits, there’s not much left of me for the future!’ ‘That’s horrible!’ I said. ‘Yes indeed,’ the reef crackled. ‘People who haven’t grown up near the reefs don’t understand how important we are for the future of local fishing and the protection of shores.’ ‘Shores?’ ‘Yes, you’ll find out in a minute!’ ‘What do you mean?’ ‘Just hold on to that sofa of yours,’ the reef danced mysteriously. ‘I’m expecting a large wave to rush over me quite soon.’ ‘Really?’ I said. ‘How do you know?’ ‘Didn’t you feel the ocean floor tremble this morning? The power of those vibrations has pushed a lot of water in our direction, and it should arrive here any moment!’ ‘What should I do?’ I said worriedly. You don’t need to worry too much,’ the reef explained. ‘I’ll be here to break some of the wave’s power, and, because it started thousands of miles away, it’s not going to be a major problem for you.’

I quickly climbed back onto the sofa and secured all my stuff. Kit was sleeping peacefully and I knew she’d hate me if I’d wake her up, but I had no choice. ‘Kit, we need to get ready for a bit of surfing,’ I joked while putting her inside my jacket. ‘What do you mean?’ she meowed anxiously. ‘Just hold onto my chest,’ I said, ‘and hopefully we’ll get to shore safely.’ ‘Why don’t you just fly away?’ Kit shrieked. ‘Be sensible!!!’ ‘I wish I could,’ I said, ‘but we need to let the engine dry out first, so….’ ‘I see,’ Kit sighed, and together we looked towards the horizon. Then, suddenly, we saw the wave. It was only a few meters high, but still, the waves we’d been riding until then were small by comparison. The tsunami slowed down a bit just before it reached us – thanks to the reefs – and when it picked us up we felt exuberant and on top of the world. But, with the beach getting closer and closer, I wasn’t so sure anymore that having lots of power was a good thing. And indeed, the sofa was smacked onto the beach without mercy; Kit and I were thrown off and hurt ourselves as we landed. Feeling completely sore, I got up and dragged the sofa to higher ground. There, I liberated Kit from my jacket and let myself collapse on the dry sand, desperately trying to catch my breath.

At the shore

After I’d recovered a bit and the ocean had returned to normal, I got up to try out the sofa’s engine. Before I could get to the right buttons, however, I had to take care of the parachute, which was in a complete mess. As I was disentangling the ropes and the fabric, I realized that the parachute had once again saved our lives, even though it hadn’t prevented us from diving into the ocean this time. But for that I blamed the huge, towering cloud that had taken us for a ride. Perhaps I shouldn’t have accepted the wind’s invitation; Grandpa had warned me not to take too many risks! I inspected the parachute and spread her out on the sand to dry. Kit got up from her resting place and decided to have a nap on the fabric. ‘Don’t you dare get your nails in there!’ I warned her. ‘Don’t worry,’ she meowed. ‘I’m too tired for things like that at the moment! Could you please get me something to eat and drink though?’ ‘That’s a very good idea, Kit!’ I said. ‘Let me quickly check the engine, because then I’ll know what our options are for dinner.’ I tried pressing the sofa’s red start button in the rhythm of Grandpa’s favourite song, but nothing happened. I tried again and again, but the engine didn’t start. ‘I’m afraid it’s going to be a barbecue at the beach tonight,’ I said. ‘And we’re going to have to sleep here too!’ ‘Here? On the beach?’ Kit meowed. ‘I don’t think so! I hate being surprised by water, and I don’t sleep much at night anyway.’ ‘Well, the engine’s not working yet, and I don’t want to call Grandpa, in case he gets worried, so we can’t go too far from here.’ ‘I’ll be going up there,’ Kit meowed while looking at the dunes behind us. I followed her gaze and liked what I saw; the dunes were higher and drier than the beach, and would probably protect us from another large wave if there were to be one during the night. ‘Alright then,’ I said, ‘we’ll move to the dunes, but first I’m going to look for some firewood.’

As I combed the beach for wood, I stumbled upon many dead fish and pieces of coral; the reef had clearly taken a battering during the massive wave that had brought us to shore. I decided to collect some of the fish for our evening meal, and returned to the sofa with plenty of wood as well. Once I’d found some matches and newspaper among my gear, I sat down in the sand to prepare my fire. Grandpa had told me to stack the wood loosely, and then to light some paper in the centre of the pile. After a few matches and sheets of paper, I was excited to see that the first pieces of wood had caught fire. The smell of fish and the crackling sound of burning wood were enough to wake Kit up. ‘Wonderful!’ she meowed. ‘I’d love some of that fish! And a warm fire is not so bad either!’ ‘Here, and some water to quench your thirst!’ I said as I poured her some water in a bowl. Kit selected her favourite fish and devoured one after the other. ‘Are you leaving those purple ones to me?’ I asked her. ‘No, I wouldn’t eat those,’ she smacked. ‘They’re poisonous.’ ‘Well, I’ll have what you’re having then!’ I said, and pierced several of the edible fish with long, sharp branches. I placed the twigs around the fire in such a way that the fish were hanging over the flames. Every now and then I turned the branches until the fish were fully grilled. When I finally tasted the results, I couldn’t believe how well my meal had turned out, and how hungry I was!

After our surprise fish dinner, Kit felt like snoozing again, and I stared into the fire for a while. The flames were getting smaller and smaller, and soon enough the fire was reduced to glowing embers. Suddenly I remembered that Grandpa had wrapped some potatoes and carrots in aluminium foil for just such an occasion. I reached behind me and found them in one of my bags. The fish had been great but not quite enough to get me through the night, so I looked forward to my roasted root vegetables. Whilst I was enjoying my treats, the burnt wood slowly lost its glow. ‘Give us more!’ the embers appeared to squeak in front of me. ‘But I need to go to bed soon!’ I replied. ‘Why can’t we burn here whilst you’re sleeping?’ the embers puffed. ‘I don’t know if I can trust you!’ I said. ‘I know you’re surrounded by sand and there isn’t too much wood lying about, but what if your sparks get blown to the dunes and reach the grass? I’d be burnt alive in my tent tonight!’ ‘Oh please, just give us a few more branches!’ the embers begged. I looked around and saw the twigs I’d used for grilling my fish. ‘Here you go!’ I said as I threw the branches onto the smouldering ashes. ‘Oh, thank you!’ the fire crackled. ‘Branches are wonderful to burn; do you have some more?’ ‘No, that’s all you’re getting from me!’ I laughed. ‘I want to sleep peacefully tonight.’ ‘Why don’t you take me to a fire-loving place then,’ the flames danced. ‘A pine forest perhaps.’ ‘Why do you want to destroy everything?’ I wondered. ‘Destroy?’ the fire crackled. ‘I prefer to think of it as recycling. And besides, many plants have grown to like me over the years.’ ‘Oh really?’ I laughed. ‘You must be joking!’ ‘Not at all!’ the flames danced. ‘In places where fires are common, I often meet plants that wouldn’t have space to grow, if it weren’t for my frequent visits. Some plants even depend on my heat and smoke for the release and germination of their seeds!’ ‘Amazing!’ I said. ‘I wouldn’t mind seeing a wildfire in a place like that!’ ‘Me neither!’ the fire burnt. ‘Can we please go there tonight?’ ‘I wish we could! But my engine’s not working at the moment; I’d love to travel to a fire-loving habitat sometime soon though, and I promise to rekindle you there!’ ‘Thank you!’ the flames flickered. ‘We’ll enjoy this moment while we can then!’ ‘Yes indeed! I will do too!’ I said, and watched the flames dance until they’d burnt their last bit of wood.

With only a few embers left glowing in the sand, I thought it was time to store away the parachute and drag the sofa to the top of the dunes. Pulling the sofa across the beach was one thing; trying to get it up some sandy hills was another. After a few minutes of climbing I realized I wasn’t making any progress at all! With each step upwards, I’d slide almost as much downwards. My feet needed something to hold onto, so I walked along the beach and scanned the hillsides until I noticed a patch of sand with several clumps of grass sticking out of it. Using the grass for support, I slowly and painfully made my way to the top; the sofa had never felt so heavy before! And that was without my gear, which I’d removed to make the sofa as light as possible. As soon as I reached level ground, I left the sofa perched on the edge of the hill, facing the ocean where the sun was about to set. It was tempting to just sit down and watch the sun get closer and closer to the horizon, but I wanted to get my tent organised first, so I raced back down the dunes and collected my gear. Having returned to the top, I looked around for a dry, grassy area and quickly assembled my home for the night. Five minutes later, I finally sat down on the sofa to enjoy a beautiful spectacle of colours.

After the light-show was over, clouds drifted in from across the ocean. With the engine needing to dry out, I decided to cover the sofa with some plastic in case it rained overnight. ‘Enjoy your hunting, Kit!’ I shouted into the darkening world before retreating to my tent. There was no reply, but I expected my friend to be looking for some warmth by the early morning, so I left a small opening in my door. Cuddling up inside my sleeping bag I felt warm, tired and satisfied. Before I knew it, I had drifted off to sleep, only to wake up again by the first rays of the morning sun. Kit had indeed found my warm bed and was snoozing peacefully beside me. Trying not to disturb her, I opened my tent door and crawled outside. When I got up and looked out over the ocean, I was shocked to see that its water level was much higher than the evening before: there was hardly any beach left at all! Was the sea level rising this quickly? Or had another tsunami hit the coast? ‘Why are you so worried and surprised?’ the water whirled below me. ‘This happens to me every day!’ ‘Really?’ I said. ‘But then these dunes won’t be here tomorrow!’ ‘What do you mean?’ the ocean waved. ‘Well, if you rise this much again by tomorrow morning, I’m going to have to climb a mountain to stay dry!’ ‘No, silly!’ the waves washed. ‘It’s only temporary! Every day, water allover the Earth gets pulled along by the moon’s course through space. Because the planet rotates around its axis, the angle of the moon’s pull changes constantly, and so my levels rise and fall in all kinds of patterns, depending on where you are in the world. When both the sun and the moon pull me along at once, I rise the most! ‘Does that mean that you’ll go down again?’ I asked. ‘Yes, of course!’ the water rustled. ‘Just wait and see!’

Relieved to hear this news, I relaxed again and lay down in the sand. Looking up at the blue sky I tried to see a sign of the moon, but perhaps we’d already passed it. Whilst I was staring into the distance, my hands started playing with the sand around me; distractedly scooping some up and letting the fine grains flow down through my fingers. ‘Wonderful, isn’t it?’ the dunes whistled below me. ‘Yes, it feels great to play with your grains!’ I said. ‘There are so many of them and they’re all about the same size; how on earth did they come together like this?’ ‘That’s a complex story,’ the dunes sang. ‘It’s quite hard for me to keep track of the history of each and every one of my little grains, but they do have some things in common.’ ‘Go on!’ I said. ‘They’ve all come from slowly disintegrating rocks,’ the dunes squeaked, ‘and were carried to the ocean by wind, rain and rivers. During their journey through water and air, the grains often rubbed together and became more and more polished with time. When the ocean rushes ashore, it can return some of those grains in the form of a beach. On dry days, with strong winds, the lighter grains get picked up from the beach and blown further inland.’ ‘And that’s how you were formed?’ I said. ‘I’m constantly being formed,’ the dunes whistled. ‘The parts of me that are closest to the ocean are often bare or only sparsely colonized by grasses. But further inland I’m quite stable, with many grasses creating a network of roots and leaves that keep my grains together and stop the wind from having free rein.’

‘But why are you more unstable near the water?’ I wondered. ‘When the winds come from that direction, they’re relatively strong, because nothing’s been in their way to slow them down,’ the dunes explained. ‘So the plants that try to grow on my ocean-facing side have to be able to withstand those strong gusts of air.’ ‘Really?’ I said. ‘Yes, but that’s not all,’ the dunes sang. ‘They also need to grow faster than the speed with which the sand rises around them. And since the wind often carries small droplets of salty water as well, they have to be quite salt tolerant too.’ ‘I can’t believe it!’ I said. ‘These grasses are truly amazing!’ ‘You’re right,’ the dunes said. Not many species of plants are able to deal with so many challenges at once.’ ‘It seems almost as challenging as living in a desert!’ I said. ‘It doesn’t get quite as hot here as in a typical desert,’ the dunes squeaked, ‘but there’s definitely not as much moisture along my foredunes as there is further inland.’ ‘Why’s that?’ I asked. ‘Partly because of the wind,’ the dunes whistled, ‘and partly because of the temperature differences between ocean and land.’ ‘Something to do with water needing more heat to warm up than rocks and soil?’ I said. ‘Very good!’ the sand sang. ‘When moist air moves from a warmer to a cooler surface, whether it is from ocean to land or the other way around, the water vapour generally takes a bit of time to cool down and precipitate, and by then it has often already passed the dunes closest to the sea.’ ‘So how do these grasses get enough water?’ I wondered. ‘They’ll try to take it up with their roots before it drains too deeply,’ the sand whistled. ‘And their leaves are designed to reduce the loss of water through transpiration.’ ‘So they don’t rely on mist?’ ‘Not really,’ the dunes explained. ‘But other plants along this coastline might do.’ ‘Let me go and explore the coast a bit more then!’ I said, and got up to go for a walk.

On the rocks

I looked around to see which way I wanted to go, and chose to leave in the direction of an interesting looking rock formation. Walking along the top of the dunes I enjoyed watching the ocean retreat while, at the same time, the beach re-appeared. The water had been right; her level was dropping after all. Perhaps I could go for another swim and soak up some sun afterwards. But first I wanted to explore the coastline a bit more. When I reached the end of the dunes and hit solid rock for the first time, I decided to stop for a break. Sitting down on the rocks with my feet in the sand, I wondered how those loose, windblown grains had ever been part of something as solid and massive as the structure I’d just stepped on. ‘It’s not that hard!’ the rock bellowed below me. ‘Oh, yes you are!’ I laughed. ‘So much so that my bottom is starting to hurt!’ ‘Very funny!’ the rock replied. ‘But you won’t get a rise out of me!’ ‘I know,’ I said, ‘you’re far too solid for that.’ ‘Solid?’ the rock replied, ‘I’m not so sure….’ ‘But you are!’ I said. ‘You’re the toughest substance I’ve come across so far, so I really can’t imagine how you can disintegrate into tiny fragments like those grains over there.’

‘Well, let me try to convince you then,’ the rocks said. ‘It all starts with the concept of time. As long as I’m exposed to the elements, I’ll slowly get “weathered” away. It may not happen within a day, but, eventually, I’ll be broken down by the actions of water, air, acidic or salty fluids, frost and temperature differences.’ ‘But I thought you were indestructible!’ I protested. ‘Every substance on Earth consists of smaller elements called atoms,’ the rock explained. ‘If you were to take a closer look inside me, you could see that my atoms are highly organized. The ordered structures in which they are bound together are called minerals, but many minerals share the same atoms, so rocks are basically a collection of ordered atom structures.’ ‘But if your atoms are so ordered, how can you disintegrate?’ I wondered. ‘Just think of what happens to a block of ice when the temperature rises.’ ‘It melts?’ I said. ‘Yes indeed,’ the rocks confirmed. When the energy of my atoms rises and they become less and less tightly bound, the solid substance on which you’re sitting right now could become fluid again.’ ‘Fluid?!’ I said. ‘You must be kidding me!’ ‘Not at all!’ the rocks replied. ‘Anything made up of smaller elements can change shape again. All you need to do is change the conditions in which it exists.’ ‘But it will never get hot enough for you to melt!’ I said. ‘I mean; it will take billions of years for the sun to heat up enough to do that!’

‘Do you think the entire Earth is solid then?’ the rocks chuckled. ‘Yes? Isn’t it?’ I said. ‘Have you never been to the centre of the Earth?’ the rocks continued. ‘No, but…,’ and I remembered the dream I’d had the previous morning, in which I hadn’t been able to stop the sofa from speeding down towards the ground, and when suddenly the earth had opened itself up to allow us to travel to its core. In my dream I’d felt hot and sweaty, and I’d been glad to wake up and realize it’d all been an illusion! ‘Well,’ I said, ‘maybe deep down I knew it was hot inside the earth, but I can’t tell you why!’ ‘It’s been a while since I was there myself!’ the rock said. ‘And I’m not sure if I’ll ever get down there again!’ ‘You see! I was right!’ I shouted. ‘Didn’t I tell you it would take billions of years before the sun might get hot enough to melt you?’ ‘Yes, I remember that,’ the rocks said calmly, ‘but we’re not the only kind of rock floating along the surface of this planet.’ ‘What do you mean?’ I asked. ‘Just look at that massive body of water over there,’ the rocks suggested. ‘Have you ever been to the ocean floor?’ I’m afraid I rejected the ocean’s invitation,’ I admitted. ‘But perhaps that was a big mistake!’ ‘Yes indeed,’ the rocks replied. ‘Because you would have discovered that the ocean floor gets recycled all the time.’

‘Oh, please tell me more!’ I said. ‘Alright then,’ the rock began, ‘I’ll do my best. First of all, what is the most obvious difference between the ocean floor and the continent on which you’re sitting right now?’ ‘The ocean floor lies much lower than you,’ I said. ‘Apparently it can take several miles to get down there!’ ‘That’s exactly right,’ the rocks responded, ‘and therein lies the answer. The ordered mineral structures of rocks on the ocean floors contain a lot of magnesium atoms, and magnesium helps to form denser structures than the minerals I have, which contain a lot of aluminium. Denser structures are heavier, and that’s why they lie much lower.’ ‘But why aren’t all rocks the same?’ I wondered. ‘That’s a difficult question to answer,’ the rocks replied. ‘For some reason, when molten rock cools, the mineral structures do not always develop in the same way. A few billion years ago, when the Earth had just formed, the entire surface was hot and liquid. When you look at the planet today, it’s obvious that the Earth cooled down enough for a diverse crust to develop, but the ways in which that happened are still quite mysterious.’ ‘Really?’ I said. ‘Can’t you tell me more about your own history?’ ‘I wish I could, but all I know is that my minerals somehow filtered out from the generally molten mix; becoming enriched in lighter atoms like aluminium. These days you can see that process in areas of the world where the planet’s oceanic crust disappears below other sections of the Earth’s crust and melts. When there are weak spots at the surface, many of the heavier minerals stay behind, while the lighter liquid minerals rise first and emerge through volcanoes, forming new continental rocks like me.’

‘Wow!’ I said, ‘So rocks do indeed melt!’ ‘Yes, of course! Especially oceanic rocks, because heavy oceanic crust always slides underneath other sections of oceanic or continental crust. That’s why you can’t find oceanic rocks that are older than a few hundred million years. Continental rocks like me can also return to a molten state, but that only happens at the edges of plates when sections of continental crust meet and push against each other.’ ‘If rocks like you can be around for a long time, why is it so hard to discover how the very first pieces of continental crust formed on the Earth’s molten surface?’ I asked. ‘You’ll have to find a piece of rock that’s old enough and still intact,’ the rocks explained, ‘and I don’t know if that’s possible. Just imagine all the waves pounding at those rocks, the ice and salt crystals pushing them apart, acidic water leaching elements out of them. Perhaps your feet are resting on some of their remaining grains right now!’ ‘Really?’ I said. ‘So you don’t think we’ll ever find the answer?’ ‘I don’t know,’ the rock admitted. ‘If you’re interested in trying to solve the riddle of the different kinds of crust, perhaps you can come up with some ideas, and then check if they could be true!’ ‘That would be great!’ I said. ‘Maybe it’s got something to do with the Earth’s molten surface not cooling down evenly and the heavier minerals staying behind in a molten state?’ ‘Do you think so?’ the rocks pondered. ‘Well, perhaps you can test your idea one day! And talking about cooling, continental rocks like me also get “weathered” a lot by the glaciers that have come and gone with the ice ages.’ ‘Ice ages?’ I said. ‘Isn’t there another one of those cooler periods due?’ ‘Why don’t you fly to the North Pole, and learn more about it there?’ the rocks suggested.

I thought that was a brilliant idea, and ran back through the sandy dunes to see if the sofa’s engine had finally dried out enough to take us to new and exciting places. From a distance I was happy to see that my plastic sheet had blown away and was no longer protecting the sofa from the elements. The combined actions of wind and sun should have helped the engine to dry out and recover from its aquatic journey. My only worry was the sand. What if some of those ancient rock particles had managed to wedge themselves between important mobile pieces of machinery? I needed to try it out, even though I was slightly nervous. Luckily the engine started, and the noises it made were quite promising. Not as flawless and consistent as I was used to, but the systems kept going nonetheless. ‘Kit!!!’ I shouted excitedly. ‘Would you like to join me on a trip to the North Pole?’ ‘No way!’ the cat meowed sleepily from my tent. ‘I’ll see you when you get back!’ ‘Ahhh, that’s a shame,’ I said. ‘Now I won’t have anyone to keep me warm!’ ‘That’s right!’ Kit replied. ‘You should learn how to grow your own fur!’ I chuckled at the idea and looked through my gear for something warm. When I finished dressing myself, I got the sofa off the ground and turned to my compass to see which way was north.

Finally I was flying again; what an amazing feeling it was to move around the world so effortlessly. I estimated that it would take me about half a day to get to my destination, so I made sure the sofa’s batteries were charging as I flew along. The views were fascinating; rivers meandering through the most interesting landscapes, and every now and then I would fly above the ocean too. When it started to look snowy and icy below me, I knew we were getting close. I slowed down and carefully followed the needle on my compass pointing north. Some time later, the needle suddenly started spinning. Feeling confused, I flew around in circles and worried that it might have broken. Moving my compass through the air, I realized that when I held it sideways, the needle pointed straight down the ground. ‘Is this it then?’ I wondered. ‘Yes, you are here,’ the Earth replied. ‘If you know what I mean by “here”, of course!’ ‘Of course!’ I said. ‘The North Pole! I’m so excited to be here!’ ‘No, this is not it!’ the Earth explained. ‘You’re at the Magnetic North Pole!’ ‘Aren’t they the same?’ I said. ‘Not really,’ the Earth replied. ‘The North and South Pole you refer to are the geographic points at which the imaginary axis around which I rotate intersects with my surface.’ ‘Really?’ I said. ‘So where are we now?’ ‘Here we are at the Northern Pole of my magnetic field,’ the Earth explained. ‘That’s why you could use a magnetic tool to find it.’

‘Magnetic field?’ I said. ‘Yes,’ the Earth continued, ‘if you were to travel deep inside me, you’d pass layers of molten rock before eventually reaching my liquid metal outer core.’ ‘Liquid metal?’ I gasped. ‘That sounds amazing!’ ‘Do you think?’ the Earth asked. ‘I just take it for granted. About four and a half billion years ago, when the sun and the planets began to form in a rotating cloud of high-energy dust and gas, I slowly grew larger and larger. Because the material from which I grew contained a lot of energy, my protected core reached high enough temperatures to melt, and so metals like iron and nickel – of which there was quite a lot – sank to my centre and formed my metal core, some of which is still liquid today.’ ‘Incredible!’ I said. ‘But how can liquid metal create a magnetic field?’ ‘Metals contain highly mobile electric charges,’ the Earth explained, ‘and because the metal in my outer core is liquid and flows around, electric currents are generated, which in turn create magnetic fields.’ ‘But why are the North and South Poles of that magnetic field so closely aligned to the Poles of the axis around which you rotate?’ ‘Well, I think your question contains the answer already!’ the Earth replied. ‘My rotation causes all the metal flows to spiral in the same direction, and this aligns the magnetic fields that are created.’ ‘Wonderful!’ I said. ‘So I can always get close to the geographic North Pole by finding the Magnetic one!’ ‘Yes, at the moment you can, but one day you may discover that by following your needle you end up at the geographic South Pole instead!’ ‘Really?’ I said. ‘Are you joking?’ ‘Not at all!’ the Earth replied. ‘I can’t control the flows of metal in my outer core; changes happen all the time. They can lead to changes in the field’s strength, or wandering of the magnetic poles; sometimes even to a reversal of currents and poles.’ ‘Is that dangerous?’ I asked. ‘I don’t know,’ the Earth rotated. ‘When the field gets weaker and eventually reverses, it may not deflect the charged particles from the sun as well, which means that I might lose some of my protective ozone layer. Perhaps you will get exposed to higher levels of UV light and cosmic rays, but I have seen early humans live through one of the previous reversals, so I think you should be fine.’

‘Phew! I’m glad to hear that,’ I said. ‘But what about the ice age we’re in? Will we be able to survive another glacial period?’ ‘Just because the current ice age, which started about two and a half million years ago, has had several cycles of glacial and interglacial periods, you can’t ask me to predict what will happen next,’ the Earth declared. ‘If those cycles continue for a while longer, then perhaps the next cooler phase is not far off.’ ‘Why can’t you be more specific?’ I said. ‘Because two and a half million years are nothing compared to the entire period of my existence,’ the Earth explained. ‘There have been some major ice ages, and several of them have lasted longer than the current one, so you could think that there might be something that causes them to last for at least 20 million years, but because there are so many factors involved, like changing levels of greenhouse gases in the atmosphere, the position of my continents, fluctuations in ocean currents, and variations in my orbit around the sun, I can’t really predict what will happen next!’ ‘Do you think that our releasing of greenhouse gases will prevent the next cooler phase from beginning?’ I asked excitedly. ‘Possibly,’ the Earth replied, ‘but I don’t know if it’s wise to get excited about that.’ ‘Why not?’ I wondered. ‘I’d much rather live in a world that’s nice and warm than having to flee for advancing glaciers. Especially with so many people living everywhere; if we all had to squeeze into a small, habitable warm zone, there wouldn’t be enough space to grow all the food we need.’

‘Well, I’m not going to comment on that,’ the Earth rotated. ‘All I can say is that if you constantly live on the edge, some day you will be pushed over it.’ ‘I agree with that,’ I said, ‘but if we can avoid certain dangers, then our lives are more stable than if we had to adjust to them all the time.’ ‘Exactly,’ the Earth continued, ‘so that’s why you need to know that there were times in my past when life in the tropics was almost completely eradicated.’ ‘Because of an ice age?’ I said. ‘No, because of intensely hot temperatures,’ the Earth replied. ‘A greenhouse out of control.’ ‘Really?’ I said. ‘When did that happen?’ ‘About 250 million years ago, when greenhouse gases rose so much and temperatures got so hot that life in the tropics didn’t recover for millions of years.’ ‘I’m glad you’re warning us,’ I said. ‘I’ll try not to underestimate the power of those gases and hope we’re not headed for an extinction like that!’ ‘I’ll have to wait and see,’ the Earth replied. ‘But it’s wonderful to be a planet that is generally suitable for life; there is always something going on, so it keeps me amused.’ ‘It seems quite amazing that life developed here in the first place!’ I said. Can you tell me more about how that happened?’ ‘Unfortunately not,’ the planet rotated. ‘If you want to find the answers, you’ll have to study life itself.’ ‘Thank you, I will do my best!’ I said, and left the polar region for warmer climates.

Life through time

As I was flying away from the North Pole I wondered how I could find out more about the history of life. The truth was that I didn’t know where to start, so I decided to go back to the rocks along the coast to have a quick break. My stomach was rumbling, and I realized that I hadn’t eaten anything since getting up! It was time for a sandwich, and perhaps that would give me the necessary brainpower to figure out where to go. I landed the sofa on the rocks and grabbed a couple of sandwiches from my bag. ‘How is it going?’ the rocks below me asked. ‘Did you find what you were looking for?’ ‘Oh yes!’ I replied. ‘The northern parts of the Earth are amazing! I can’t believe how much I’ve learnt about the planet and it’s history! But now I’ve got another topic I’d like to explore; I’d really like to know more about the evolution of life.’ ‘That shouldn’t be a problem!’ the rocks said assuredly. ‘This coast harbours many secrets about times past.’

‘Really? I said. ‘What do you mean?’ ‘Well, remember I told you about weathering?’ the rocks asked. ‘Those processes by which newly formed rocks get eaten away by the elements?’ ‘Yes I do,’ I replied. ‘Some of the remaining grains of those weathered rocks now make up these dunes.’ ‘Exactly!’ the rocks continued. ‘But not only that; they form soils as well. When sediments are deposited over time, the deeper layers may eventually become rock again.’ ‘Are you sure?’ I said. ‘I can’t quite believe that the loose, windblown grains that shape these dunes can somehow stick together to form a solid piece of rock.’ ‘That’s because you’re forgetting something,’ the rocks continued. ‘Let’s imagine that these dunes do indeed get covered by more and more layers of sand and other sediments. The weight of those top layers will compress the deeper layers so much that the spaces between the grains become as small as possible. If this part of the coastline happens to be sinking slowly, then the deeper layers will one day find themselves below the water table. When that happens, groundwater carrying dissolved ions will move through the layers and fill the remaining pores with minerals.’ ‘So minerals precipitated from groundwater will cement the grains together to form stone?’ I said. ‘Yes indeed,’ the rocks explained, ‘but you don’t necessarily need groundwater to do that; it can happen at the bottom of lakes and oceans too.’

‘Amazing!’ I said. ‘But what does that have to do with the history of life?’ ‘Plenty!’ the rocks said. ‘Because sometimes, organisms happen to get caught and covered by flows of sediments – on land or in the water – and then go on to experience the same rock-forming processes as the grains around them. For example, waterborne minerals can precipitate in the empty pores within their tissues, or, when their entire body dissolves, they can leave a hollow or mineral-filled space behind. Then, when sections of continental crust press against each other, the deeply buried sedimentary rocks can be lifted up again. That’s why rocks made from sediments are such a great place to look for fossils.’ ‘I’d love to hunt for fossils!’ I said. ‘Do you know where can I find those preserved signs of ancient creatures?’ ‘If you follow this coastline south for about two hundred miles, you will come to a long stretch of tilted sedimentary rocks, where each layer harbours fossils from a different period of the planet’s past. I’m sure you will enjoy yourself over there!’ ‘That sounds great!’ I said. ‘Thank you so much!’

I couldn’t wait to leave but wanted to say hello to Kit first. ‘Where are you going?’ she meowed as I circled the sofa around her snoozing spot. ‘I’m off to hunt for fossils,’ I shouted. ‘Would you like to go with me?’ ‘Hunting? But of course!’ she squealed. ‘Why don’t you lower the sofa so that I can jump onto it!’ That sounded like fun, so I circled around once more and then took the sofa on a low fly path above the dunes. The first time it was still too high and Kit couldn’t quite make it. The second try was perfect, as Kit managed to bury her claws into the sofa’s wood and pull herself up to her seat. ‘There we go!’ I said, and turned the sofa into the right direction. Flying along the coast we saw some amazing cliffs and hidden beaches. I was tempted to stop in each and every bay, but the lure of finding fossils was stronger still. When we finally reached the promised rocks, I landed the sofa on the stony beach below them and immediately started hunting for mineralized signs of life. I couldn’t believe my eyes when, on my way towards the cliff, I spotted a beautiful fossil lying on the beach in front of me. It was quite large, and its spiralling shape reminded me of ocean creatures, but I couldn’t remember having seen anything quite like it in real life. ‘You’re right,’ the fossil said. ‘You can only find traces of me these days. None of us are alive.’ ‘Really?’ I said. ‘When did you live? And why did you get extinct?’ ‘With the right tools, you should be able to answer the first question yourself!’ the fossil said. ‘I wish I could!’ I said. ‘But I’m afraid I need some training!’

‘The secret lies within original, unweathered rocks,’ the fossil explained. For example, volcanic rocks formed from the molten mineral mass that reaches the Earth’s surface, or meteoritic rocks that formed alongside the planet and the rest of the solar system and which have since landed on Earth.’ ‘What’s so special about those rocks?’ I wondered. ‘They are special because you can assume that all the atoms inside them have been there since the rocks were formed. Some of the atoms they carry are radioactive, which means that the elements’ composition changes over time.’ the fossil explained. Because of that, you can measure the amount of original atoms and the amount of changed elements and calculate how much time has passed for that amount of decay to happen.’ ‘But I thought that fossils are mainly present in sedimentary rocks; rocks that are made from the weathered products of many different original rocks.’ ‘You’re right,’ the fossil continued, ‘and that’s why you can only measure the age of original volcanic or meteoritic rock layers between which other layers of fossil-bearing sedimentary rocks are sandwiched, unless the creature got caught in the volcanic mass itself.’ ‘Well, I don’t carry the right tools with me to do all those measurements at present!’ I said. ‘Could you please tell me the answers anyway?’

‘Ok then,’ the fossil replied. ‘I used to be an ammonite, and my species lived in the open ocean for several hundred million years.’ ‘And then what happened?’ ‘About 60 million years ago, we died out during a major extinction phase, together with many other species, including dinosaurs.’ ‘Incredible,’ I said. ‘What could have caused something like that?’ ‘I don’t know,’ the fossil replied, ‘but we did notice that it was a lot darker and that there was less and less to eat for us and our babies.’ ‘Why was that?’ I wondered. ‘Something, like lots of dust in the atmosphere, must have blocked sunlight from reaching the ocean.’ ‘I vaguely remember hearing something about that,’ I said. Didn’t it have something to do with dust-spewing volcanoes and collisions with meteorites?’ ‘You tell me,’ the fossil said, ‘but all I know is that there was a lot less phytoplankton around.’ ‘Phytoplankton?’ I said. ‘Yes, those tiny organism that float along the surface of oceans and make sugars and oxygen from sunlight, carbon dioxide, and water. A lot of larger creatures in the ocean are dependent on phytoplankton for food, so I guess we weren’t competitive enough.’ ‘What do you mean?’ I said. ‘Well, if there is a limited supply of food, then the number of animals who can sustain themselves will go down, and in our case our babies depended on plankton. If on top of that we are increasingly hunted by other animals, who are also hungry, then species whose numbers dwindle the most may become extinct.’

Couldn’t you find a way to deal with the changes?’ I asked. ‘That’s a very interesting point,’ the fossil replied. ‘But perhaps you should view extinctions at a higher level.’ ‘What do you mean?’ I said. ‘Well, I think our extinction had more to do with the world as a whole than with our ability to change,’ the fossil explained. If you think about the planet’s surface with its continents, oceans and atmosphere as one large, interconnected space that is colonized by different forms of life, then you may find that unless that biosphere has room and resources in a particular area, and unless the cycles of life require a certain function for which there are no other species available, any given species can become extinct.’ ‘Really?’ I said. ‘That sounds scary!’ ‘Why’s that?’ the fossil asked. ‘Each individual will die anyway; why don’t you enjoy the life you have?’ ‘But I thought we were indispensable!’ I said. ‘At least I would really like to be!’ ‘Perhaps you can become that,’ the fossil said, ‘but we didn’t worry about such things. Whilst there was room for us, and enough resources to live, we enjoyed being part of the biosphere’s fluxes.’ ‘So you didn’t have a special function?’ I asked. ‘We had plenty of functions!’ the fossil replied. ‘We consumed lots of plankton and other small ocean critters while larger animals liked us as part of their diet. But whether that was “special” in the sense of being unique? I don’t think so. There were many other species in the oceans who ate plankton and fed larger creatures, so in that sense we could be missed.’ ‘And if there hadn’t been any similar species?’ ‘Then perhaps we would have survived, but only if the circumstances would have allowed it.’ ‘What do you mean?’ I said. ‘Well, if there hadn’t been any plankton around in the upper water layers, then nothing else, including us, would have been able to live in that part of the ocean either.’ ‘Like when the Earth’s land and ocean surfaces got really hot and a lot of life died out in the tropics many millions of years ago?’ ‘Exactly,’ the fossil said. ‘In the end, life only exists within certain ranges, and temperature is one of them.’

‘But what about micro-organisms that are adapted to really high temperatures and who live deep down in oceans near hot vents, away from sunlight?’ I said. ‘You’re right,’ the fossil said, ‘it depends on the habitat we’re talking about. Life that evolved near hot vents is obviously used to high temperatures, but life that evolved in cooler parts of the ocean, or on land, definitely isn’t. But just because some organisms can stand a condition that others can’t, doesn’t mean that there are no limits for life as a whole. The “extremophiles” are the life forms that define the lower and upper limits of life-sustaining ranges. After all, there are regions on Earth that are almost sterile, like some extremely dry deserts. As far as I know, life on Earth can’t exist without water.’ ‘Yes, but that’s because the Earth’s surface is two-thirds water and you are a water-loving creature yourself!’ I laughed. Maybe there are planets where life evolved without water, by using a completely different kind of liquid to survive.’ ‘Who knows?’ the fossil said. ‘I’ll let you find out more about that!’ ‘Maybe I will!’ I said. ‘But before I get carried away, could you tell me more about the evolution of life on Earth?’ ‘I’ll do my best,’ the fossil replied. ‘Let me see what I can remember.’ ‘Just start at the beginning!’ I laughed. ‘Thanks for the suggestion,’ the fossil said dryly, ‘but you have to realize that we weren’t around at that time; we evolved much later.’

‘So who were there first?’ I wondered. ‘That’s a very good question,’ the fossil replied. ‘I don’t think that those earliest creatures are still around! After all, most species die out at some point, and many of them do not even leave hints of their existence in the form of fossils!’ ‘But what were they like?’ I continued. ‘Well, if life evolved here on Earth, as opposed to arriving from elsewhere in the cosmos via meteoroids and asteroids, then its earliest forms must have been very simple.’ ‘Like archaea or bacteria?’ I said. ‘No, much simpler than that,’ the fossil said, ‘but similar in the sense that they were probably single cells.’ ‘But I still don’t understand why life developed in the first place,’ I said. ‘How can molecules interact to form cells that use energy and elements from their environment to grow and reproduce?’ ‘Those are difficult questions to answer, because it all happened so long ago,’ the fossil explained. ‘The building blocks for some of life’s important molecules, such as proteins, RNA and DNA, were probably created by the energy and elements present on a young Earth. But in order to form even the simplest protocell, many processes must have come together, and the sequence in which those steps happened, and where and how, remains largely unanswered.’ ‘I can see I have a lot of work to do!’ I said. ‘I would ask some of your friends to help you!’ the fossil said. ‘Otherwise you may never find the answers!’ ‘Maybe you can help me along a bit more,’ I said, ‘because I’d really love to know how ammonites and humans evolved from tiny protocells! ‘I’ll do my best,’ the ammonite said, ‘but you shouldn’t expect fossils to show you all the answers!’ ‘Perhaps I will add my own experiments in the future!’ I said. ‘But for now I’d just like to learn everything that’s already known.’

‘Alright then,’ the fossil continued. ‘The first protocells lived around four billion years ago, and about half a billion years later, they must have evolved into a community of cells that were ancestral to all life currently living on the Earth.’ ‘Really?’ I said. ‘So we’re all derived from the same early life form?’ ‘In one way or another!’ the fossil laughed. ‘The evolution of life has often been quite complex!’ ‘What do you mean?’ I asked. ‘Well, the relatively simple bacteria and archaea were present early on, and they are still the most abundant forms of life today, having adapted to the most extreme environments, and even living in and on larger organisms like us. Fungi, plants and animals on the other hand are derived from eukaryotic cells. Eukaryotic cells have a complex history, because they seem to be a symbiotic fusion of archaeal and bacterial species, in which the bacteria evolved into sub-cellular compartments like mitochondria and plastids.’ ‘That sounds very complicated indeed!’ I said. ‘So without bacteria and archaea and their interactions, most complex forms of life wouldn’t be here?’ ‘Exactly!’ the fossil said. ‘Without the evolution of eukaryotic cells, in which mitochondria derived from engulfed bacteria provide the symbiotic cell with extra energy, the evolution of larger organisms with many genes and complex structures wouldn’t have been possible.’ ‘Amazing!’ I said. ‘Does that mean that all multicellular organisms are eukaryotes?’ ‘Not really,’ the fossil replied. ‘Prokaryotes are simpler because they don’t have mitochondria, chloroplasts or other membrane-bound organelles in their cells, but some of them, like species of cyanobacteria, can still form multicellular colonies, in which certain cells become specialized in particular functions, such as getting nitrogen from the environment. At the same time, there are many eukaryotic species which are unicellular.’ ‘So, collaboration between cells has evolved both in prokaryotes and eukaryotes?’ I said. ‘Yes indeed!’ the fossil continued. ‘But all larger-sized organisms are eukaryotic, since they benefit from having more complex and powerful symbiotic cells.’

‘Then why are we carrying so many prokaryotic bacteria with us?’ I wondered. ‘Someone told me that the bacterial cells in our bodies outnumber our own!’ ‘Because the bacteria were there before us, and so we co-evolved with them,’ the fossil explained. ‘Instead of having to develop everything independently, we let them do some of the work for us, since they were around anyway.’ ‘Work?’ I said. ‘Yes,’ the fossil continued. ‘Helping to digest food for example; that way we manage to get all the nutrients we need to grow and sustain ourselves.’ ‘Really?’ I said. ‘I thought that most bacteria were harmful to us.’ ‘Well, there are harmful ones too!’ the fossil said. ‘But fortunately our cells can recognize many of those invaders and rally against them to control infections without destroying our collaborators or our own cells.’ ‘That must be incredibly complex!’ I said. ‘I have no idea how my body does it!’ ‘It’s very difficult indeed,’ the fossil explained. ‘But even your immune system may be getting help from organisms living within you. Unfortunately the body makes mistakes sometimes; attacking some of our own cells because they resemble the invader too much, or because the beneficial organisms which help control our immune responses aren’t there.’ ‘That doesn’t sound like fun.’ I said. ‘But then it must be hard to respond correctly all the time; what with so many different molecules, cells and organisms – all within one larger organism!’ ‘Yes, unfortunately things can go wrong when you have so many cells working together.

Another example of that is cancer, where some cells start growing in ways that are not beneficial to the animal that they’re part of.’ ‘If that’s the case, then why don’t plants get cancer?’ I asked. ‘That’s a very good question,’ the fossil said. ‘The reality is that plants have evolved independently from animals for a very long time, ever since they separated ways about one and a half billion years ago. Plants – as opposed to animals – developed a fibrous wall around their cells, and so their cells are fixed, and don’t travel throughout their structures like in animals, which means that cancerous cells are contained and don’t spread further.’ ‘But they do get tumours, don’t they?’ I asked. ‘Yes they do,’ the fossil said. ‘Some species more than others.’ ‘Do you know why?’ ‘Perhaps the plant species that develop fewer tumours have more copies of genes available to control growth.’ ‘More copies?’ I said. ‘A lot of plants are polyploid,’ the fossil explained, ‘which means that they have more than two copies of each chromosome, and therefore more than two copies of each gene. If an important gene stops working, then a polyploid plant may have several other genes available to perform a similar function in the plant’s life.’ ‘I see,’ I said. ‘I hadn’t realized that having so many copies of chromosomes would be a good thing!’ ‘Maybe not so much for mobile creatures like you and me, but plants seem to do quite well with it; once they put their roots down, they are stuck in a particular place for the rest of their lives, having to deal with anything that comes their way. So you can imagine that having a few extra chromosomes could be a good thing; it allows them to keep backup copies of important genes, or it can be a basis for the development of new and useful functions.’ ‘Really?’ I said. ‘So plants evolve by doubling all of their chromosomes?’ ‘Yes, but it is more common for an organism to duplicate only parts of them,’ the fossil said. ‘And that’s just one way of changing; there are many others too!’

‘Go on,’ I said. ‘Well, organisms can also change by receiving small pieces of DNA from another species,’ the fossil explained. ‘Quite a lot of your DNA has come from viruses for example, including a gene that’s important for a baby’s development in the mother’s womb.’ ‘That sounds incredible!’ I said. ‘We really are strange creatures!’ ‘DNA also travels quite often between different species of bacteria,’ the fossil continued. When bacterial cells are close together, they can form a connecting structure, and it’s through this structure that DNA can travel from one organism to another.’ ‘Amazing!’ I said, ‘It sounds a bit like mating!’ ‘It does indeed!’ the fossil said. ‘Except that mating usually happens between two organisms of the same species. But even so, mating is definitely another way of creating changes in organisms, because the children of two parents will have a random mixture of their parents chromosomes, and in every new generation, some of the DNA will change spontaneously, but most of the time those changes won’t affect the function of a gene.’ ‘And if it does?’ I wondered. ‘Then the effect is often harmful, and sometimes beneficial,’ the fossil replied. ‘If the effects are neutral, or if they are actually helping to give the organism or species an advantage, or a new ability, then those changes will become more and more abundant, until they are widespread.’

‘Are changes necessary?’ I asked ‘They’re part of life,’ the fossil explained. ‘They can happen in many ways – some of which we’ve just talked about. As long as new forms of life can live and reproduce on this Earth, they will do so.’ ‘Unless something stops them, like in your case?’ I said. ‘For example,’ the fossil replied. ‘But so far, life itself has not become extinct on this planet.’ ‘It has only changed?’ ‘Yes indeed,’ the fossil said. ‘It changes anyway, and the longer it is allowed to reproduce and change, without becoming extinct, the more it spreads to wherever it can go.’ ‘Although sometimes it’s stopped in its course,’ I said. ‘Not always,’ the fossil replied. ‘If the changes are temporary and mild, then the organism is generally flexible enough to change the way it handles things, by adjusting the amount of protein it makes, or how active its proteins are, or by escaping the threat by moving to regions of the Earth where the circumstances are still the same. But when the changes are drastic, then many species can become extinct at once, and only the organisms who are best adapted may survive and evolve into new species who thrive in the drastically different situation, like having oxygen in the atmosphere for example.’ ‘I remember the wind telling me about that,’ I said. ‘Precisely!’ the fossil replied. ‘Free oxygen wasn’t present in the atmosphere until photosynthetic cyanobacteria started producing it. Once the oxygen was there, organisms for whom oxygen was toxic either became extinct, moved elsewhere, or evolved into species that could handle it.’ ‘Like me, for example?’ I said. ‘I guess so!’ the fossil said. ‘Because otherwise you wouldn’t be standing here breathing air every few seconds!’ ‘But why wasn’t the oxygen toxic to the bacteria that started making it?’ I wondered. ‘During ancient ice ages, UV light was involved in liberating oxygen from water vapour, and ice also played a role in this process, so the bacteria living in the oceans nearby glaciers must have evolved to deal with small amounts of oxygen, before they started producing it themselves.’

‘Amazing!’ I said. ‘So not all species go extinct?’ ‘It depends on how you look at it,’ the fossil replied, ‘because species can evolve into new species, so even though a species has gone extinct, its offspring may still be around today.’ ‘Really?’ I said. ‘Is that true for humans too?’ ‘I think so,’ the fossil said. ‘Quite a few fossils that somewhat resemble humans were found in old sedimentary rocks, whereas fossils that match you very closely are much younger, so obviously there were human-like species before you that must have evolved into what you are today.’ ‘So, some time in the future, we will probably look quite different,’ I said. ‘Possibly, although some species seem to have changed very little on the outside compared to the oldest fossils they resemble. But that doesn’t mean that they aren’t changing, or that they’ll never become extinct. They just happen to live in places that are very stable, like the deep sea, where there isn’t much competition either. ‘Well,’ I said. ‘I hope humans can keep external change under control, so that we won’t suddenly go extinct, and instead remain quite similar, or slowly evolve into new species,’ I said. ‘I do admire your confidence,’ the fossil said. ‘We ammonites never believed we could stop large rocks from bombarding the Earth, or volcanic dust from blocking vital sunlight, or the climate from changing.’ ‘I’m not too worried about those things,’ I said. ‘We’ve sent rockets into space before, so I’m sure we could find a way to deal with asteroids. As for climate change, I hope that we’ll be able to keep our biosphere’s temperature within a comfortable range. Not only for ourselves, but for many other forms of life as well, although we could do without a few diseases!’

‘I wish you and your offspring all the best for the near future,’ the fossil said, ‘but you shouldn’t forget that the Earth will one day become inhabitable for all forms of life, including extremophiles.’ ‘You’re right,’ I said. ‘The sun told me as much. I guess that means that life itself will have to find a new home?’ ‘I hadn’t thought of that!’ the fossil said. ‘But it sounds like a fabulous idea!’ ‘Thanks!’ I said. ‘I don’t actually know how life could possibly do that, but I’ll try to sleep on it tonight!’ I looked around to see if Kit was anywhere near me, and she turned out to be closer than I thought. ‘I can’t believe how lazy you are!’ I laughed when I spotted her lying on the sofa. ‘Weren’t you excited about going hunting with me?’ ‘Hunting fossils?’ the cat said sleepily. ‘No thanks! I’m not going to waste my time chasing creatures that have been dead for millions of years!’ ‘Oh, I’m sorry to hear that!’ I grinned. ‘Let’s go back to the dunes then and have some proper food instead!’ ‘That sounds good,’ Kit meowed, ‘because I was getting a bit worried; you were looking at that ammonite for hours!’ ‘Well, the history of life turned out to be a bit more complex than I thought,’ I said, ‘and I have a feeling that the future of life is not much simpler!’

In the cosmos

‘Let’s get going,’ I said, whilst starting the sofa’s engine. ‘I’d like to be back before the sun disappears!’ ‘Don’t worry about that,’ Kit said reassuringly. ‘As long as there is a little bit of light, my eyesight should be good enough to show you the way.’ ‘But of course!’ I said. ‘Our eyes must have evolved quite differently, because your night vision is much better than mine!’ ‘I knew you’d appreciate it one day!’ Kit meowed. ‘I’ll just pretend that your tent is worth hunting for!’ ‘Thanks!’ I said. ‘I’ll fly as fast as I can!’ As the sun was setting along the ocean to our left, the colours of the world slowly lost their intensity, until everything around me reflected various shades of darkness. ‘I think we must be getting close now, Kit,’ I said a little while later. ‘Please keep an eye out for my tent!’ ‘I’ll do my best!’ Kit meowed as she leaned over the edge of her seat to scan the terrain below us. ‘What do you think?’ I asked her. ‘I think you’ve gone too far,’ she said. ‘It’s far too rocky around here.’ I turned the sofa around and reduced my speed. ‘Here we go!’ Kit meowed a few minutes later. ‘That’s your tent over there!’ ‘Where?’ I asked her. ‘Just fly a bit lower,’ Kit suggested, ‘and I’ll tell you when to land.’ ‘I took the sofa down until I started to get worried. ‘Now!’ Kit screamed, so I quickly put on the brakes and hoped for the best. The sofa came to a very bumpy halt, and both of us got thrown left and right. ‘Your night vision may be better than mine,’ I said, ‘but you’re not a great pilot!’ ‘Well, at least you don’t need to walk very far,’ the cat replied. ‘I made sure you landed right next to your tent!’ ‘Thanks a lot, Kit,’ I said. ‘I think I’m just going to have a quick sandwich now before heading to bed.’ ‘I’ll see you in the morning then,’ Kit meowed. ‘I’m in desperate need for some real food; especially after those disappointing fossils!’ And off she went, leaving me to enjoy my cold sandwiches in the dark.

I started to feel a bit lonely, when, suddenly, the cloud cover resolved and the darkness gave way to a bright moon and an overwhelming number of distant suns. Slowly, the world around me became visible again; not quite as colourful as with direct sunlight, but enough to make me feel that I could roam around all night long without getting lost or feeling unsafe. The dunes and the ocean looked fabulous, and I felt immensely happy to have the moon there to send some sunlight my way. ‘I’m glad you’re enjoying the light,’ the moon reflected. ‘It’s quite a miracle that I’m here at all!’ ‘Really?’ I said. ‘How come?’ ‘Well, the large rock that started it all could easily have flown by and forged a different future for itself. But out of all things, it happened to collide with a young and growing Earth!’ ‘I’m not sure what you’re talking about,’ I admitted. ‘Are you saying that you didn’t form alongside the Earth?’ ‘That’s right,’ the moon continued. ‘The Earth had already half formed and was still accumulating dust and debris when an object the size of Mars smashed into it.’ ‘That sounds incredible!’ I said. ‘So what happened next?’ ‘Some of the object’s material must have flung back into orbit, creating me – the moon – and some of it may have increased the size of the Earth. After the impact, both the Earth and I continued to receive smaller objects and other debris, until we reached our current size.’ ‘Amazing!’ I said. ‘Who would have thought that the moon and the Earth were so intimately connected? Not only do you cause the oceans to rise and fall throughout the day and night, but you share a bit of rocky history with the Earth as well!’ ‘Yes indeed,’ the moon shone. ‘When you study my rocks you’ll know that that’s true!’ ‘Maybe I’ll visit you some day!’ I said. ‘But for the moment, I’ll admire you from afar!’

After a while, my eyes drifted away from the brightly beaming body and started exploring the rest of the night sky. The longer I scanned the depths of space, the more distant suns I seemed to discover. Suddenly, one of the stars shot off like an arrow, leaving a trail of light behind. ‘Wow!’ I said. ‘I think I’ve just seen my first shooting star of the night!’ ‘No, silly,’ the moon reflected. ‘That was just a bit of solar system debris.’ ‘Solar system debris?’ ‘Yes, like the material that made the Earth and I grow larger and larger.’ ‘Really?’ I said, ‘Was it just a piece of rock or metal entering the Earth’s atmosphere?’ ‘I’m afraid so,’ the moon shone. ‘You can’t call it a star just because it looks as bright and tiny as those distant suns.’ ‘I see…. Well, in that case, I’m happy to have seen a meteor!’ ‘Precisely!’ the moon reflected. ‘Now you’re talking!’ ‘Thanks for the clarification,’ I said. ‘It all makes a lot more sense now; I did wonder how a star could ever suddenly accelerate like that and travel to a new place in the cosmos!’ ‘Me too,’ the moon continued. ‘Whereas meteors enter the higher atmosphere quite often.’ ‘I think you’re right!’ I admitted. ‘The Earth must have grown a bit larger tonight!’ ‘Especially if some of the material reached the surface!’ the moon radiated.

I tried to detect some more meteors, but the night sky didn’t light up again. What I did notice though was that one area of space seemed brighter – with more stars – than the rest of the sky. It was almost as if a huge, milky cloud of distant suns had wound itself around the Earth. ‘You’ve made a very interesting observation,’ the cosmos echoed. ‘But the stars aren’t actually circling around the Earth. They’re rotating around a central area in space; something so powerful that it pulls billions of stars along in its wake, one of which is the sun.’ ‘Really?’ I said. ‘So the solar system is not its own little cluster in the grand scheme of things?’ ‘Not at all!’ the cosmos replied. ‘The sun and the surrounding planets are part of a spiralling galaxy: a disk-shaped, star-studded whirlpool of space. The milky cloud you mentioned is the area in which the density of stars is the greatest, but the visible suns outside of that band belong to the same galaxy.’ ‘Amazing!’ I said, ‘I hadn’t realized that we’re part of a huge system like that. ‘Are there more of those whirling structures around?’ ‘But of course,’ the cosmos expanded. ‘Many more than you can see, although some of them are quite close by.’ ‘Can you point one out to me?’ I pleaded. ‘Yes I can,’ the cosmos replied. ‘If you turn to the right and look at those bright stars over there, then somewhere between them you might see a small, cloudy patch.’ It took me a while to adjust my eyes, but then I spotted it. ‘Is that really another galaxy? I wondered. ‘Yes indeed,’ the cosmos explained. ‘Only two and a half million light years away.’ ‘That sounds scarily far,’ I admitted. ‘Oh, don’t worry,’ the cosmos vibrated. ‘It’s getting closer as we speak. Just wait a few billion years and it will be colliding with this milky galaxy of yours.’ ‘Are you serious?’ I said. ‘Of course I am!’ the cosmos said. ‘It’s all part of the great cosmic dance of spacetime.’

‘But why are you dancing like this?’ I wondered. ‘Where did you begin and where are you going?’ ‘I’m not going to tell you,’ the cosmos vibrated, ‘because it would take away your reason to live and learn ever more.’ ‘You might be right,’ I admitted. ‘It’s quite exciting to find out more about this strange environment we’re living in.’ ‘And what have you found out so far?’ the cosmos wondered. ‘I’ve heard that faraway galaxies seem to be moving away from the Earth – and from each other,’ I said. ‘They say that you’ve been expanding ever since you were very dense and hot, about 13.8 billion years ago, and that you might be expanding faster and faster.’ ‘And what makes them think that?’ the cosmos quizzed me. ‘Apparently, when people look at the light coming from stellar explosions, they see that it has changed in a way that means you’re expanding faster. Is that true?’ ‘I’m not going to reveal all my secrets at once,’ the cosmos echoed. ‘But how can I explain everything if I don’t know everything?’ I sulked. ‘That’s exactly my point,’ the cosmos danced. ‘If I were to tell you about everything that lies behind your horizon, you would probably not believe me, so you’re going to have to find ways to keep pushing your boundaries. If you do that, you will understand more along the way.’ ‘So, there’s no sense in giving up as yet?’ I said. ‘Not at all!’ the cosmos echoed. ‘Look how far you’ve come! It would be silly to stop trying now!’ ‘But what if the cosmos ends? Or expands so much that it loses all its energy?’ ‘If that were the case, do you know how long that would take?’ the cosmos danced. ‘Much, much longer than the life of that sun of yours. And, besides, since I’m everything, my future will be decided by everything, including you.’ the cosmos whirled. ‘That’s a great thought,’ I said. ‘I know that I’ll return to stardust one day, but between now and then, I do like to think that I play a role in my own life’s unfolding, and the future of the world around me.’ ‘Exactly,’ the cosmos danced. ‘The future is being created all the time.’ ‘Wonderful!’ I said. ‘If I can help shape the future through my actions, then that gives my life a sense of meaning, as I can set things in motion that perhaps won’t happen without my being here.’

‘That sounds promising,’ the cosmos danced. ‘So, what are you wishing to do?’ ‘First of all, I would try to live in a way that allows us, or our evolved offspring species, as well as all the other species we’re connected with, to survive on this Earth until the sun gets too hot, in a billion years from now.’ ‘And how would you do that?’ the cosmos quizzed. ‘Well, if we can keep the larger threats at bay, such as huge asteroids and extreme climate change or epidemics, then I think the main thing to try and do is to sustain our population for as long as possible.’ ‘That’s not as easy as it sounds,’ the cosmos commented. ‘Why not?’ ‘Because some of the things you’re using right now to sustain yourselves might run low in the near future.’ ‘Like what?’ ‘Oh, there are so many of them!’ the cosmos explained. ‘Fresh water, soil minerals for plant nutrition, rare earth minerals for all your technical devices, oil and gas from dead plants for energy, fresh fish for food, threatened plant species for new medicines…. ‘So, what can we do to prevent all those things from running low and disappearing? I wondered.’ ‘That’s easy!’ the cosmos echoed. ‘You have to become much better at recycling and conservation, whilst using sources of energy that are renewable, such as sunlight, wind and tidal power – the cosmic energies of the sun and the moon!’

‘Alright!’ I said, ‘I’ll do my best! And if we do indeed manage to live here for quite a while longer, in a sustainable way, then I hope that we, as part of life on Earth, can send life to places in the cosmos where it so far hasn’t evolved. Perhaps we could start by sending space-travelling packages full of photosynthetic extremophiles to young, Earth-like planets nearby.’ ‘That sounds exciting!’ the cosmos danced. ‘A bit more biological drama around is always entertaining!’ ‘Perhaps we ourselves can spread too,’ I added, ‘and continue our path of evolution on other habitable planets or moons, especially on the ones where we’d feel most comfortable; which are most like our cradle, the Earth.’ ‘And how would you do that?’ the cosmos vibrated. ‘First we’d need to find good homes, of course, and then we’d have to develop a way to get there quickly enough. But if all that were possible, we could travel there and build our own supportive biosphere – a closed system that recycles our air, water and wastes – in which we’d grow our food and live for as long as necessary, whilst transforming the world around us – starting with a breathable atmosphere – until the new planetary biosphere is ready for us to leave our little bubble.’ I peered into the depths of space and wondered where such new homes could be found. The moon had disappeared beyond the horizon, but the increased darkness was filled with the light of billions of stars, twinkling in the sky. Suddenly I felt myself rising quietly, being lifted effortlessly into space by my own flying sofa. I was embarked on a timeless journey, visiting one solar system after another. Traveling far away from the coast, the ocean, Kit and Grandpa, until the Earth was only the tiniest of dots, slowly disappearing out of sight as I moved into new cosmic realms.

End