The bus is inside a cloud; there’s no longer a view from the window.

Louisa opens a notebook and starts to jot down some ideas for her new programme. A friend at Imperial College London persuaded her to get involved in student radio a year ago, and she has developed something of an addiction. She looked forward to her weekly slot, its sense of being together, alone: shut inside a studio, pressing illuminated buttons and gliding sliders on the panel, speaking words anyone in the world could hear.

Yet there might be nobody listening – maybe just a handful of students at her own university tuning in. This was a comfort to Louisa when she first began. Perhaps, if she made a mistake, no one would notice. Her live-radio anxiety covered two extremes: she might run out of things to say or else get carried away and blurt out something stupid, ruining her credibility as a researcher.

When she told Marcus, her thesis supervisor, that she had been successful in her application to spend a year at Muchachos, the first thing he said was, ‘This will be good for you: finally you’ll be able to focus on your research instead of your little radio programme.’

Whenever their discussions led to some breakthrough in Louisa’s understanding, about the composition of a star, or the movement of a planet, Marcus would spot her eyes moving heavenward. ‘More material for Skygazing!’ he’d say, shaking his head. ‘Good research takes time, Louisa, time for sustained thought. This dabbling in media is a distraction.’

But half the pleasure of discovery was sharing it, Louisa thought. Otherwise, she would be talking into a closed vessel, one that contained the world’s most highly respected researchers, to be sure, but a limited community for all that. If knowledge wasn’t relevant to the wider world, what was the point?

A few e-mails to Janet Penney, Director of Research at the Observatory, was all it took to arrange a regular recording space for ‘Moons of Muchachos’. In fact, it was Janet’s suggestion that the first programme should be recorded in front of an audience of fellow researchers, so that everyone at the Observatory would know about her media outreach work and might consider taking part in future editions. Her programme would go out live every week, then appear as a podcast on the Observatory’s website. What a relief to have a supervisor who cared about connecting with a modern outside world.

The clouds clear as the bus emerges, two kilometres above sea level. The road widens, shaking itself free from the hairpin bends that made them all queasy on the way up. Like giant mushrooms, the white globes that house the telescopes pop into view. The bus’s wheels crunch over the gravel of an informal parking lot edged by bright tufts of green grass that broaden into fields of wildflowers. There are sighs of relief from the new cohort of researchers as they descend from the bus, inhale the fresh air, and collect their enormous backpacks and suitcases packed with months’ worth of necessities.

Louisa parks her suitcase and looks out the circular windows of her room in the brutalist accommodation block, shaped uncannily like a flying saucer. One window, near the floor, looks down at a fluffy sea of clouds, the other, near the ceiling, at a clear blue sky. She can hardly wait for sunset when she’ll finally get to see the night sky as every astronomer wishes it to be: free of light pollution, pure and clear, like you’ve put on a brand new pair of magical glasses, and can take in light years of distance in a moment’s glance.

Louisa descends the long iron staircase outside her block and crosses the wildflower lawn to the low, triangular building that houses the lecture halls and researchers’ offices. The glass doors at its corner slide open as she approaches, and she consults a panel to find the Director of Research. No names are listed: just job titles and office numbers.

She walks down a corridor lit faintly by skylights, and taps on a pale green door. It’s opened by a tall woman with short cropped hair and round, black framed glasses.

‘Louisa! Nice to meet you finally. Come on in.’

Guiding Louisa towards the nearest chair, Janet sits down behind her enormous desk and leans as far across it as possible, as if she wishes the desk weren’t there to separate them.

‘I’ve had a look at your podcast website. Very impressive. We’ve already set up a special section on the observatory’s website so you can upload the audio there right away. I’m keen to see what kind of public impact this is going to make.’

‘Thanks. It’s an exciting place to be recording! I hope lots of people will be curious and phone in.’

‘I’d really like it if you could get the other researchers involved in this too, but it won’t be easy. They’re so caught up in their work, they don’t often make time for anything else.’

Janet pauses and her animated gaze becomes, for a moment, distant. ‘But,’ she resumes, with a little knock on her desk, ‘it’s important for them to learn how to talk about their research in an accessible way – when you’re publicly funded, the least you can do is reach out and tell the public what you’re up to! I’ll make that clear to the new arrivals when I introduce you tonight – they might be easier to convince than those who’ve been here longer...’

When Louisa returns outside, it’s twilight. There’s a man in the wildflower field with a large leather glove. A glossy falcon with a tiny head and keen eye soars down, lands on his wrist, and accepts a twisted scrap of meat.

‘I know what you’re about to ask,” the man says, catching Louisa’s fascinated gaze. “This is an actual job, not a hobby of mine. Though it’s Geneva who’s doing most of the work: she keeps the swallows away so they don’t foul the site.’

Small birds scream as they nose-dive into the clouds. Louisa looks up.

‘The sun’s barely set, and you can see the same number of stars as we do in London.’

‘Just wait ‘til it’s properly dark,” he says quietly. ‘I never get tired of looking at the sky here: every planet and constellation, shooting stars....’

‘It’s an amazing place to work.’

‘It is that. But be careful: some researchers get bored up here, and the things they do to distract themselves can be cruel sometimes.’

‘I was just talking to Janet Penney, and she gave me the impression that everyone’s completely focused on their work.’

He nodded. ‘Everyone here’s serious about their work all right. But as you can see, there aren’t that many distractions, and everyone needs a break from work sometimes. Some people organise film nights, others do a bit of mountaineering, but there’re a few who like to play games.’

‘Is there someone in particular I should be watching out for?’

‘I don’t want to set you against any of your new colleagues – you’ve only just got here. These things happened a few years ago, and lessons were learnt. At least, I hope so. But Dr. Penney won’t give you any warning. I’m external, so I’m freer to talk about some of what I’ve seen.’

‘What happened, exactly?’

‘Stupid practical jokes, with serious consequences,” he said. “For instance, someone created a fake copy of a journal to make it look like one of the researchers had plagiarised someone else’s work. Of course, the man in question knew he hadn’t stolen someone else’s research, at least not purposely. But the fear that he might be ostracised from the academic community...That night, he took too many sleeping pills. We flew him by helicopter to a hospital in Tenerife, and he survived. But he never came back: he was too angry when he found out what his colleagues had done. I think he went to work at the observatory in Hawaii. They’re not bad people here, but forewarned is forearmed.’

After so many broadcasts alone, it feels a little odd for Louisa to be sitting at the front of an auditorium filled with 150 people: nearly everyone who works at the Observatory is here. Janet has just introduced her, and she sees some smiles in the audience: whether encouraging or skeptical, she’s not sure. There’s an old-fashioned corded telephone at her elbow, and a large microphone on the table in front of her. The technician at the back does a final sound check and gives her the thumbs up.

‘Welcome to the first edition of Moons of Muchachos, broadcast live in front of an audience of researchers at the Observatorio del Roque de Los Muchachos, in La Palma, Canary Islands,” she says. “I’ll be talking about my research and interviewing colleagues about theirs. You’ll have a chance to phone in and tell us if we’re boring you with technical mumbo-jumbo, or ask questions about anything space-related that’s on your mind. This week you’ve got access to an especially rich pool of expertise: most of the researchers at the Observatory are here with us, so please call in with your trickiest questions, and we’ll try to answer them.’

Louisa is surprised to find the phone already ringing. Her work on the website, Facebook page and Twitter feed is paying off. When she had her live programme at Imperial, some weeks nobody called at all; she’d had to text her old friends from high school, begging them to phone in with a question.

‘Hello, this is a call from Canada.’

Louisa recognised her mother’s voice. ‘Yes, caller, what’s your question?’

‘A lot of us listening have never been to an observatory before. Could you give us a sense of what it’s like up there? And is it possible for members of the public to visit?’

Louisa describes what she’s seen of the Observatory so far, relieved that Mum hasn’t given the game away. Then she hands over to Janet who explains the Observatory’s visitor policy and says that they’re about to start a volunteer scheme for astronomy enthusiasts wanting to become research assistants. Louisa hopes her mother won’t consider this an invitation.

As soon as she hangs up, the phone rings again.

‘Hello, you’re on Moons of Muchachos.’

‘Hello.’ The voice is reedy yet husky, as if an insect had caught a cold.

‘Do you have a question?’

‘Is there space to park a vehicle at your observatory?’

‘Very practical questions today! Please remember, listeners: you have at your disposal nearly every researcher at the Observatory. Do you have any questions you would like to ask about the universe?’

‘The route to the Observatory is planned. Please provide information about parking possibilities.’

‘Sounds like alien intelligence on the other end of the line!’ someone shouts from the audience.

‘Hurry up and answer the question – that’s one hell of a long distance call!’ says someone else.

Everyone laughs except the caller. A knot forms in Louisa’s stomach. Five minutes in, her programme’s becoming a joke.

‘Thank you, caller. There’s ample parking for all authorised visitors to the Observatory, so please apply through our website if you’d like to come and take a look at what we’re doing.’

There are no further calls. A couple of fellow researchers gamely join Louisa at the microphone to talk about their specialisms. But she’s lost her ability to draw them away from excessive detail as she normally would. Both the black hole specialist and the expert on the moons of Jupiter give ten-minute jargon-filled monologues that would put any normal person to sleep.

When the half hour is up, Louisa draws the programme to a close. She is tempted to say something impulsive, to kill Moons of Muchachos after its very first episode. Will she have to put up with this nonsense every time she has a phone-in? Are her new colleagues so childish?

She texts her friend Stanislava back at Imperial.

1st ep: disaster! Practical joker phoned in pretending to be alien with parking query.

She receives an immediate response.

Haha! Should do that every episode: astronomy comedy, your new signature!

Louisa smiles. Stana always finds the bright side. Maybe she’s right: harness the joker to her advantage.

Louisa finds Janet in the administrative office, locking away the key to the lecture hall.

‘Is there any way of finding out where those calls were coming from tonight?’

‘I’m sorry you didn’t get more of them,” Janet said. ‘That last one was quite odd! But it’s the falconer who looks after our switchboard. He has his house a little lower down the mountainside. I’ll drive you there tomorrow if you like.’

Louisa wakes up early, her mind alive with new ideas for incorporating comedy into her programme. She goes out for a walk. The wildflowers sparkle with dew. Tufts of cloud creep over the edge of the mountain and float just above the grass. The sun is rising above the globe of the largest telescope, like the end of an eclipse. Louisa sees the falconer silhouetted against the horizon, Geneva circling above his head.

‘Good morning. Janet tells me that you operate the Observatory switchboard.’

‘Hello there,’ he says. ‘Yes, that’s right. You’re lucky to catch me here: Geneva normally only works once or twice a week, but I discovered a new colony of swallows as I was driving down the mountainside last night. We have to let them know who’s boss!’

‘Did you notice where the calls were coming from last night?’

‘Just the one call. Dr. Penney told me there might be a lot of people phoning in for your programme. I was sorry to see there was just that one from Canada. But chin up! I’m sure you’ll get more next time.’

‘That can’t be right: there were two calls last night. One after the call from Canada.’

‘Nothing came through our switchboard.’

Louisa pauses and looks up at Geneva, circling.

‘It was nice of you to warn me about the practical jokes that go on around here,’ she says, finally. ‘So I don’t understand why you’re trying to protect the joker’s identity. I’m not angry about it or anything. I actually found the joke funny, and I’d like to make it a regular part of my programme.’

‘I’m not sure I follow. You say there was a second call after the one from Canada?’ The falconer’s face darkens. ‘I wouldn’t protect anyone who plays tricks on their colleagues, I can promise you that. It was me who tracked down the graduate students who made the fake journal – I scanned the logs on all the printers. I’m happy to say those individuals are no longer working here. But what was this second call you received?’

‘Someone putting on a funny voice, pretending to be an alien looking for parking at the Observatory.’

The falconer didn’t smile. He pressed a button on a small clicker and Geneva returned to his glove. He looked around, as if to check they were truly alone.

‘Last night, the driver of the bus that brought you here decided to stay overnight; there was poor visibility on the roads back to La Palma. When everyone was gathering in the auditorium for your programme, I was about to call Geneva back. I was going to let her finish her chase before I went home to work the switchboard. But she gave up her stoop suddenly, for no clear reason. She returned to my glove, seemed to be cowering there – more like a rabbit than a bird of prey. I looked up to see if a larger bird had frightened her. I saw something that looked like a shooting star, but it was coming towards me. It got larger and larger, like a giant ball bearing: as though one of the telescopes had become mirrored, and floated up into the sky like a bubble. I couldn’t tear my eyes away, I couldn’t even blink. Then it disappeared.’

‘Thanks. That explains a lot.’

Louisa begins to walk away. The falconer must have made the call. He’s the practical joker, with some sick desire to alienate her from her fellow researchers.

She feels a hand on her shoulder.

‘Please, don’t tell anyone here what I just told you,’ he said. ‘I didn’t expect you to believe me: you’re a scientist after all, you want physical proof. I’ve seen things before, even stranger than what I’ve just described. You don’t know how lonely it is, keeping them all to yourself. It drives me mad: why can’t it happen when the researchers are at their telescopes? Why does it only happen when I’m by myself?’

‘Okay,’ says Louisa, to end the conversation. She returns to the saucer-shaped accommodation block, wondering whether the falconer is just vindictive or completely mad.

Louisa makes a strong coffee in the kitchenette in her room. She sits on the floor to drink it, gazing down at the gathering clouds. It’s a strange place to be, and your mind goes to strange places when you’re up this high.

As soon as the clock turns to 9:00, she heads over to Janet’s office for advice.

‘I’ve had some interesting conversations with the falconer.’

Janet’s face lights up. ‘Such a kind man. Everyone here has so much respect for him. He would have liked to be an astronomer himself. We’ve tried to convince him to go back to school: he left when he was fifteen, but he can’t see the point of adult education. He says that by the time he graduates, he’ll be too old to make any valuable contribution. Such a shame – he’s been with us for the past 20 years.’

‘He warned me to watch out for my fellow researchers.’

Janet clasps her hands, pounding the desk gently.

‘Obviously, in my official capacity, I can’t greet new arrivals with warnings about professional rivalry. I’m sorry about that idiotic call you received last night. Unfortunately, it’s far from the worst incident we’ve had. Maybe the falconer told you about it.’

‘He told me the story before I received that call. But I saw him this morning and he denied there even being a second call. I can’t help but think he’s the one who made it.’

Janet shook her head. ‘He’d be the last person to play a trick like that. You know, odd things happen here sometimes. Electrical short circuits. Strange sound waves. We put it down to a combination of altitude, powerful telescopes, and who knows what else.’ She laughs. ‘We won’t suspect alien interference until we have proof!’

Louisa goes back outside and sees the bus driver climbing into his seat. The bus sways off over the gravel and starts down the road back to La Palma. The parking lot is empty, and Louisa looks up at the sky.