Science Show Summer - The Extremely Large Telescope
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ABC Listen. Podcasts, radio, news, music and more. Time for a special science show. Yes, I know they're all supposed to be special, but this is extremely so. Remember that word extremely. It's in the name of one of the most gigantic experiments in human history, set in one of the driest places on Earth.

But here's another puzzle. After Hubble and the James Webb in space, why do we need yet another telescope here on a distant mountain? Jonathan Webb reports from that extraordinary place. I've just stepped out of the residence and I can't see a thing. You just have to sort of slow down and stop and hope you don't bump into anything. And after a while, you start to see the horizon.

and everything around you is dark and everything above you is lit up. It's not actually much of the Milky Way at the moment but there's no shortage of stars. Oh! And now the laser from the telescope's just gone. If you look closely enough you can see several lines in the laser even from down here. Why am I in the middle of the desert rambling about the stars and watching lasers shine into the sky? Let's go back a bit.

I'm in northern Chile, and I'm here to see something big. So big, I spotted it easily from my plane window on the flight in. There's a road snaking to the top of a mountain with its summit flattened, and a huge domed skeleton hunches on top.

It's flanked by cranes leaning upwards and the whole setting appears to reach up above the rocky plains and dunes, punching out of the desert towards the sky. Which feels appropriate because that colosseum-sized building houses the next chapter in our story of the universe. We are already descending to Andresa Vela airport of Antofagasta. And I'm going to meet the people putting it together. It's going to...

Ever since Galileo took a tube with two lenses, pointed it at Jupiter and discovered moons, we've been getting better and better at staring into space.

We built bigger lenses, then curved mirrors to collect more light. The bigger the diameter of the mirror, the more stuff you can resolve. We sent telescopes into space for a sharper view and listened for longer wavelengths with huge radio dishes. And every time we found a way to look further to get more clarity, astronomy jumped forward. The universe always manages to surprise us.

Today we're on the brink of a new era of giant telescopes. Here in the Atacama Desert is the biggest of them all for collecting visible light. A telescope that big is just mind-boggling. You can't really imagine what it looks like. It will be the most powerful optical telescope ever built. How and why is a team of people building this thing in the middle of the desert?

Water is brought by trucks. It's like Disneyland for astronomers really. What are they up against? What's it like? I'm feeling really emotional. Sometimes there are tough moments. We will not fall. Is it worth all this effort? And who will get to use it? This is make or break for our field in this country. And what will this new chapter reveal that we've never known before? It's between 10 and 20 times sharper images.

It's going to prove everything that we know is wrong, so we start from zero. But we love this. This is the Extremely Large Telescope, the ELT to its friends. Thank you for your flight with LATAM for your safety. Please remain seated until the... Before I can see it up close, there's a two-hour drive further into the desert. It's a landscape like I've never seen before, like there's a bitumen road on the surface of Mars for some reason.

I don't see a tree or even a plant the entire way, just gravelly plains and dunes and eventually rocky mountains, but all with smooth rounded edges and all the same pastel brown. It's as if the land has been sanded down by time. I'm here in Chile as a guest of the European Southern Observatory, or ESO. That's the consortium of European countries that's building the extremely large telescope.

From a wide valley, the ESO minibus turns off and climbs a steep ridge and we pass a checkpoint to reach our first stop, Paranal Observatory, at 2,500 metres above sea level.

This is home base for the ELT project, and it's where ESO already runs a very successful set of large telescopes. Sneaking out of the hillside in slabs of red-brown concrete is the Paranal Residence, a temporary home for the people who work the telescopes. It was actually used as the Bond villain's desert lair in the film Quantum of Solace, where they pretended to blow it up.

But as we venture inside down a long gentle ramp and slip away from the harsh light of the desert, it's cool,

and car. What you see here, it's a very nice lobby. The idea is to have this green area, which of course helps or enhances the well-being of our staff. Vanessa Pedro is the head of logistics and facilities in this oasis for astronomers. The entrance hall has a big garden inside it, sloping down to a pool that's only partly for swimming. You have the swimming pool also creating or helping a bit the humidity because we have very, very low humidity levels.

Vanessa's right about the humidity. When you step in here, you realise just how dry it was outside. It feels like your skin relaxes. A row of big square windows highlights the contrast between inside and outside. Fierce sunlight on pebbles stretching to an empty horizon.

On this side of the glass it's another world entirely. So you will see everywhere lots of things that always try to make this place feel at home outside of home because our staff they spend here more or less half of their life. As we move through the residence down long concrete corridors, quietly past doors where some of the astronomers might be sleeping,

Around nearly every turn, you see big containers of water lined against the walls. Yes, the water is brought by trucks. We have around 600 trucks per year, which is huge. More or less 12 trucks per week of 30 cubic metres. It's quite a lot. We really...

are making a lot of efforts to improve our spending in water and to become much more sustainable because this is really, in talking about the future, this is really for us one of our main goals. I find it amazing that this whole enterprise is here for one reason and it's not ecotourism or industry, it's all in the service of science. That's something nobody seems to forget.

Above us is a huge round skylight with an equally huge umbrella that folds out automatically at night. Not to keep anything out, but to trap the light inside. Since this is an astronomical observatory, it's very important not to create light pollution at night. You will see everywhere that you have shutters and curtains that really avoid us.

creating light pollution. Sure enough, there's a sign in multiple languages in my business-like single room. No smoking and shut the blinds at sunset. So after an early dinner, I obediently close all the blinds and head up the hill behind the residence to see the sunset over the clouds. Sunset is the start of the work day for astronomers and there's a small crowd gathered here for a moment of peace before things get busy.

So depending on what the science team have planned, the engineering team typically hands over the telescope to the science team, usually around sunset, sometimes could be an hour before, depending on if they need to do some calibrations. And then that becomes our responsibility. Elias Sedegati is a quietly spoken staff astronomer for ESO. We're sheltering from the breeze behind a metal building eight storeys high, gleaming in the setting sun.

There are four of these buildings on top of the hill above the residence, each one the size of a small block of flats and each housing its own telescope with an eight-metre mirror. The four giant instruments can work separately or as a team and together make up the very large telescope. It's the pride and joy of ESO. The mirrors of the VLT captured the first ever direct image of a planet outside our solar system.

They traced the movement of stars around the black hole at the centre of the Milky Way. And this very large telescope has blazed a trail for the extremely large telescope, which is taking shape 20 kilometres away across the desert and another 500 metres above sea level.

The ELT will open up a completely new frontier. A 39-metre mirror is a vast bucket for collecting light, the biggest ever built, so it will be able to see much fainter objects in the distant universe. It will also pick out incredibly fine details.

The bigger the diameter of the mirror, the more stuff you can resolve. So you can think about when a car is coming towards you and when you're driving on the road. When the car is really far away, the two headlights seem like just one point. And at some point when it gets close enough,

your eyes can actually resolve the two things. So how far away you can resolve these two headlights depends on how big the diameter of your eyes. These are the same thing. These are eyes on the sky. So the bigger the size of the mirror, the further away you can resolve those two points. Eliar and his colleague Eleanor Asani are working on software for the ELT and on how that even bigger telescope up the road can be run from the same control room as the VLT just behind us.

Eleonora says they can't wait to see what this new mega telescope will do. ELT is going to be a revolution. I mean, each single observation with ELT is going to be mind-blowing, something that has never been seen with such a depth, with such granularity in the details of the data that you can observe.

So it's going to allow us really not just a step forward, a jump, I'd say.

So we have theories and then we do observations, we adjust those theories and then we think that, oh, we know everything. And then ELT comes along and it's going to push these boundaries and then whatever we find beyond that is going to prove everything that we know is wrong. So we start from zero. But we love this. We love this as scientists because it allows us to refine our theories. So that's what I look forward to, to prove us wrong, all the current theories that we have.

As well as delighting at the possibility of reducing time-tested theories to rubble, Elia and Eleonora are excited by the technical challenges they face.

Eleonora's eyes light up with pride as she explains they're working at the edge of what's possible. Each instrument is unique. There is no one else similar to it on planet Earth. So to maintain, to keep it performing and to execute observations, you need really someone that is specialised in it. And

I like to think of us as Formula One pilots. Formula One pilots are those that optimize their car so that it can perform and win the race. We are doing more or less the same. We do optimize our instruments, we do keep our instruments performing so that our users can get the best from them.

As I leave the F1 telescope drivers to their night's work, I ask whether there are any secrets to having a good night in the control room. Bring chocolate on the mountain. If you are an astronomer visiting us, you really need to bring chocolate. And with chocolate, we can almost guarantee good sky conditions. Almost good weather. Yes, exactly. With good weather, low sky turbulence. Yes, chocolate.

There are plotted trends of a sky turbulence against the presence of chocolate in the control room. Because we are scientists, you know, we prove things. While the night shift gets busy pointing the telescopes, recording data, solving problems and sharing chocolate, I try to get some rest before we visit the ELT tomorrow.

My little room in the residence, with the light off and those blinds tightly drawn as instructed, is pitch black. I don't know if it's the jet lag or the excitement or the dry air, but I can't sleep a wink. I had to do an online safety briefing before visiting Paranal. There were videos warning about the low humidity and high UV. They didn't mention insomnia. But I was warned about high levels of static electricity in the desert.

And when I eventually give up on sleep and push the covers off the bed, I see blue sparks of static charge crackling in the darkness, stranded on my blanket by the dryness of the air. This place really does feel like another world. That's when I pull on some shoes, make sure the lights are all off, and step outside. It is completely black in a way that I have never experienced before. And after a while, you start to see...

the horizon and the sky starts to look light. I can see so many stars, just so many. And you can understand how a telescope out here can see so much further, so much clearer. Because even I can see quite far and quite clearly. There are no clouds or maybe a tiny wisp of cloud near the horizon and the rest is just this

carpet of light sources. And now the laser from the telescope's just gone. You can see it starting over on the hill where the telescope is and just shining up in a dead straight diagonal up into the sky until it disappears. And that's what they're using to calibrate the mirror.

Being outside in that sort of darkness, watching the universe expand around you as your eyes adjust, is a profoundly memorable experience. The lasers are a part of the adaptive optics of the VLT. It's a system that cancels out the effect of the atmosphere so the telescope can take clear images with no twinkling or smudging, almost as if it's actually out in space.

Four laser beams shine into the upper atmosphere about 90 kilometres up, where they hit sodium atoms and energise them, igniting four artificial stars. The twinkling of those steady fake stars is recorded, and that real-time measurement is fed into one of the telescope's mirrors to change its shape. A thousand tiny ripples per second, driven by tiny electronic pistons under the mirror's surface.

It's a calibrated, rippling mirror that dampens the twinkling of the stars to get a clear view. A bit like the way noise-cancelling headphones silence the aircraft noise, so you can hear your podcast. The ELT will have this system too, but as with everything, it's on a totally different scale. Next morning, after a rest but no sleep, that's where I'm headed.

I'm back in the ESO minibus for a half-hour drive further into the desert to get up close with the future of astronomy. This is why I've come all this way. The road winds slowly between hard brown dunes and ridges, and before long, the massive, levelled-off shape of Cerro Armazones, the mountain home of the ELT, starts to drift in and out of view.

At 3000 metres, it's the highest point as far as the eye can see. And it really looms over the desert. But it's not smooth like the other shapes in the landscape. It stops abruptly in a flat, stadium-sized platform with the hulking silhouette of the ELT squatting on top. A skeletal steel dome surrounded by cranes and a cloudless blue sky.

We pull up in a cluster of sheds tucked into the shoulder of the mountain. And here in a site office in the desert with hard hats on hooks and blueprints on the walls, I meet Davide Diana. He's the deputy site manager of the dome and main structure of the ELT.

But with his fluoro vest and down-to-earth, unflappable vibe, he could be a building site manager anywhere. Before we climb to the platform and see the telescope up close... Davide quickly rattles through some of the practicalities of his job.

building the biggest optical telescope in history. It will be the most powerful optical telescope ever built with 39.2 meters in diameter for M1. He starts serving up numbers. 798

As if picking them off incredibly orderly shelves in his brain. Just to recap, the main mirror of the ELT will be 39 metres across. That's bigger than four tennis courts and physically impossible to manufacture in one piece. And to compensate for warping under gravity when the telescope tilts,

Each of its 798 segments will have three pistons, so it can be individually adjusted. Just to give another numbers about the complexity... I'm listening. Each segment has 12 edge sensors in order not to crush the segments when adjusting them.

and this gives us again 9,600 roughly proximity sensors. Of course there are roughly 9,600 sensors to stop the segments from bumping into each other. And M1, the main mirror, will bounce the light into five more specially engineered mirrors before sending it to an instrument for the scientists to measure and analyse. It goes to M1, that is basically the biggest mirror that we have. It goes reflected to M2,

and from here it goes to M3, again reflected to another M4 mirror, again to another M5 mirror. In reality there is another M6 mirror over there.

M4 is worth a particular shout-out, Davide says. The fourth mirror in the chain is where the real-time input from the laser beams shining into the sky will filter out the turbulence of the atmosphere by physically reshaping the mirror. That's another... Gotcha. Cool.

Oh, and of course, the whole building rotates. Think about it, 6,100 tonnes of mass rotating at a velocity of plus minus two degrees per second. Then inside the dome, the telescope rotates separately. We will have 4,600 tonnes of mass for the telescope.

And this is where it becomes tricky and fascinating because the precisions that we request are much higher. Wait, this is where it gets tricky? All the structure is sliding on top of something like 70 microns of oil. It's called a hydrostatic bearing system. A telescope the size of the Colosseum will spin around on literally a hair's width of lubricating oil.

Think about 4,600 tonnes of rotating mass moving at a precision that goes from tens to thousands of arc seconds. That's millionths of a degree. It means that at the edge of the telescope's circular floor, which is 54 metres across, it can stop within thousandths of a millimetre. The accelerations are not that high, but the precision is quite impressive. Yaha!

Oh, and if the telescope rotates all the way round and keeps going, they've thought of that too. This is some high stakes cable management. The telescope can move 540 degrees. So you need a special system that allows the cables to not get stretched or damaged during the rotation.

Even the gradual shrinkage of the concrete itself over the next 30 to 50 years has been carefully calculated and allowed for. So everything has to work perfectly. I mean, we are pushing the current engineering limits. Everything has to work together, like, I would say, like a symphony.

Even Davide, the level-headed site manager who's worked on big telescopes before, has a special feeling about this one. It's a tough environment. I mean, this is for sure. But you have to love the job. This is, you are building something that is one in a lifetime project. I mean, if you are working here, it's because you love what you're doing.

And you're listening to The Science Show on Radio National from the highest and driest parts of Chile. Jonathan Webb. Finally, we drive up the steep road that twists and turns to the summit. It's cut into the side of the mountain and we inch along in case there's a construction vehicle around the next bend. As we take the final couple of turns and draw up to the level of the telescope, nobody says anything. Even if you've seen this thing before, it can really take your breath away.

And then the wind takes your breath even further away. It's gusting at 50 kilometres an hour straight off the Atacama, which ripples away below us all the way to the horizon. Up here on the platform, tall cranes are standing still on their caterpillar tracks, but swaying gently against the sky. If you turn to the telescope, it's impossible to absorb in a single glance. So you focus on details.

Sunshine glinting on the curved steel frames at the top of the dome, 22 storeys up. Columns of scaffolding reaching up the sides. Nobody's there today because of the high wind. Slabs of concrete footings curving away from you in a way that really does make this feel like a modern-day coliseum.

Huddled behind one of these fresh concrete walls, I speak to someone who is giddy with excitement just to be here. So my name is Juan Carlos Muñoz and I'm the ESO Media Officer and I'm based in Aachen in Germany. But you used to be an astronomer, or still are an astronomer. They used to do your astronomy down the road. Correct, yeah. In my previous life I was first an ESO Fellow and then an Operations Staff Astronomer at Paranal for seven years, from 2013 to 2020.

When Juan Carlos Muñoz did his astronomy just a few kilometres away at the merely very large telescope, the extremely large telescope was just a flattened mountaintop and a design. Now its steel frame is soaring into the sky above us, and underneath the hard hat and safety glasses, Juan Carlos is visibly bouncing up and down with delight.

I'm feeling really emotional. I remember when I used to work at the VLT, like, you know, at the end of the night, we would just drive down the summit and I would always see the flat top of Cerro Armazones. So I was always imagining how it would look like. And now finally seeing the steel structure of the dome taking shape is really, really special for me. And we're at 3.5.

thousand meters just over above sea level in the middle of the Atacama Desert. It's just incredibly sort of desolate and remote. Why put this telescope here? There are several reasons. First of all, as you said, we are quite isolated, so we are really far away from any source of light pollution.

Also the quality of the atmosphere here is exceptional. We have more than 300 clear nights in a year and in addition to that the quality of the atmosphere is very good in the sense that there's very very low turbulence because we want to get very sharp images. Also like why so high? Well we want to be in a very dry and high place because water vapour can affect certain observations like in the infrared for instance. So we want all those things. We want something very far away from light pollution

with a very stable atmosphere and very, very dry. How are you feeling? What are we, four years, five years out from completion? Yeah, so the first scientific observations are planned for 2028. And yeah, like everyone is really, really excited. Of course, I share that enthusiasm. I couldn't be any more enthusiastic about this.

Juan Carlos is a mild-mannered bloke who speaks quietly and quickly. But you can tell that at this moment he is actually breathless. He's seen diagrams and photos and knows the design of the ELT inside out. But nothing compares to standing here in the desert wind and seeing it. This titanic machine is built for looking up, but it faces danger from below.

Twice a day on average, the ground here in Chile is shaken by an earthquake of magnitude 1.5 or bigger. And they do get big. It's the same violent tectonic collision that built the Andes Mountains. And it's not finished. OK, so what we can do, we go now to the Graf Foundation.

Davide Deana leads the climb down inside the foundations to see how this immense but intricate device can survive if the mountain moves. So all around here you see different components. So you have the black ones, 96 in total they are

high-dumping rubber bearings. So basically they are specific seismic isolators on the horizontal plane. The whole $2 billion telescope is floating on seismic isolators, so when a quake comes it can be cushioned horizontally and vertically. The grey ones are called leaf springs, like the flexure plates that you have, let's say, in standard trucks.

Like suspension on a truck. Yeah, I mean they are... they do the damping in the elevation axis. So this is what allows the telescope to survive the earthquakes here in Chile. And if we go in this direction,

The extremes of this environment, from the buffeting wind and beating sun to the shaking Earth, have to be factored into every aspect of the telescope's construction. When it comes to the main mirror, every one of its 798 hexagonal segments must have a tiny gap on each of its six sides. As tiny as possible for the sake of the images, but wide enough that the mirrors won't crunch into each other during a tremor.

That mirror will be the glittering jewel at the heart of the ELT. The telescope's ability to detect the farthest, faintest galaxies or to pinpoint rocky planets orbiting faraway stars will rest above all on the precise engineering of a curving, gleaming 39-metre honeycomb.

And now that I've paced around the massive rotating building where it'll live, I'm off to see where that centrepiece is coming together. Back across the desert, nestled behind the James Bond lair of the Paranal Residence, there's a collection of big workshops and hangars. One of them has the lofty ceilings, bright white lighting and squeaky floor of an industrial cleanroom.

In my notes, I call it the Hall of Mirrors. And mirrors are what keeps Tobias Müller up at night. If you have cleaned your windows at home, you know already that it's nothing easy, no? So you do it three times and then you go to the correct angle and you see, oh no, it's not really clean. But here it's a completely different level. You need extremely experienced technicians.

who can look with a special light on the surface and any single spot they detect has to be cleaned. We're inside the clean room wearing shoe covers, lab coats, gloves, hair nets and face masks. Every stray particle in here is a hazard to science. Staring out from between bits of safety gear, Tobias's eyes are intense. He's in charge of testing and putting together all the telescope's components. It's not a small job.

You can imagine close to 800 segments with millions of parts. You need to maintain the exact configuration because imagine something is configured wrong.

and you would give a signal to move a motor and there's moving something wrong. How can you find it once it is installed on the telescope? Configuration management here in this room but also on the telescope is one of our biggest challenges to maintain at any time software, mechanical, electrical configuration up to date. Because if you are failing in that, the telescope will not work.

When I visit the facility, the cleanroom is almost completely empty. But there's a sense of anticipation. We're in the tense calm before a very careful storm of activity begins, when hundreds of mirror segments will start to arrive, shipped all the way from Germany in refrigerated containers. This roller door is the entrance area and behind the roller door there is an airlock. In the airlock,

The cover is removed, the box and the segment assembly is cleaned and from inside of the airlock we open the roller door and there is where the cleanroom process starts. Each hexagonal segment is about the size of a kitchen table made from ceramic glass with a QR code to designate its eventual position in the honeycomb of the main mirror.

In this room they'll be meticulously checked and cleaned, fitted with their electronics, motors, sensors, receivers and transmitters. They'll be sprayed with a layer of silver and a protective coating that's microscopically thin. Then they'll be stowed away on coated shelves ready for assembly on the telescope. It's an incredibly expensive jigsaw puzzle. If we move the segment from the storage

The whole configuration is moving to the telescope and there's exactly one position we can install the thing. So for that, we have a huge team in the background developing software, working with asset management systems, defining templates, implementing new procedures which has never been seen before. And our expectation is once we start with the first segment, it will be everything perfect. We will not fail. No pressure, hey?

Everyone here seems to feel that the stakes are high. This is Tobias' colleague, Philippe Guitton. Sometimes there are tough moments, but you think about the moment, you know, you have a brand new telescope and you just open it and get fantastic results. And that's a big motivation.

That moment is what it's all about, what all these people are working towards. When the mirror segments are all correctly assembled up on the mountain, fine-tuned and ready to start catching light. Everything is wired up, the whole building rotates and the 900 ton mirror tilts towards its first target in the sky, each segment making small adjustments as the structure bends under its own weight.

and the five other mirrors bounce the collected light into scientific instruments and somewhere in a control room a lucky astronomer watches an image materialize that's never been seen before. That's when the fun actually starts.

Later on, back in the cool calm of the residence, Juan Carlos Munoz dares to dream about the future. The whole ELT project officially passed 50% completion in mid-2023. So far, so good. Given how things are going now, we should be on the sky by 2028. Juan Carlos is the astronomer turned media officer who shared his giddy excitement while we sheltered from the wind beside the ELT itself.

He's still smiling about it. It almost feels like it's difficult for him to sit still while we chat about the ELT and what it'll do. This is basically my first time back where the dome actually looks like a dome and the feeling of massive hugeness, which is I guess the only way I can think of describing it, is absolutely unmatched. It's not only the sheer size of the structure but also knowing how precisely it has to move. It's just...

I couldn't really explain how I felt beyond saying that you know it felt quite emotional. So it's definitely cool and impressive this telescope but why do we need it right? Like we have the VLT just up on the hill behind us which has four very impressive telescopes which can also be joined together to work as a set so where is the need for an even bigger optical telescope

here on the ground. So building a bigger telescope gives you two perks: seeing sharper details and seeing fainter objects. With this trick of interferometry, where you link several telescopes together, you only get the first perk, which is being able to resolve very, very, very small details. But if you want to see something that is very faint, there is no way around it. I mean, you cannot make light out of thin air. You really, really need a mirror that is

as big as you can. That's interesting. So linking them together helps with resolution but not with sensitivity. Exactly, yeah. There are other big telescopes proposed but this is sort of the biggest and the furthest along, isn't it? How does it measure up to other proposals from competitors, for want of a better word, friendly competitors in other parts of the world? Yeah, yeah.

So there will be like three 30-40 meter class telescopes. The giant Magellan telescope, the GMT, which is being built by several institutions in the US. It's also in Chile, a bit further south from where we are. That one is 25 point something meters wide. I think they're still at the level of the foundations and they have been making progress with the mirrors, for instance.

As far as I know from the latest schedule, they are aiming for shortly after the ELT. End of the decade. Yeah. So it's not a race, but you're ahead. And then the other one that is also further behind that will be the 30-meter telescope, also being built by the US. So ESO, the European horse in this giant telescope race, is comfortably out in front.

In fact, the other two proposals, the giant Magellan telescope further south in Chile and the 30-metre telescope in Hawaii, both led by America, are both in limbo. Between them, they need US$3 billion of extra funding, and they're asking the US government for support.

But after spending $10 billion on NASA's James Webb telescope out in space, Congress may need some convincing to foot the bill for either of these giant instruments on the ground. The 30-metre telescope might even have to move because it's faced fierce opposition from Indigenous Hawaiians over its proposed location at the summit of Mauna Kea. So I asked Juan Carlos about ESO's relationship with the people of Chile. ♪

Whenever you talk to someone on the street, like, you know, say you take a taxi to go to the airport or whatever, the moment you mention that you are an astronomer, their eyes light up because they are really proud of this really natural heritage that they have, which is the night sky. And they are really interested in what we can learn from it. So they are really proud of all these telescopes that we are building here.

In terms of Chile's First Nations people, it was the Atacameños who originally inhabited this desert. But after waves of colonisation, Juan Carlos says very little remains of their culture. The largest surviving indigenous group is the Mapuche, and the four telescopes of the VLT have names from the Mapudungun language. Antu, Cuellin, Melipal and Ayepunt, which means the sun, the moon, the southern cross and the morning star.

Chilean governments and communities have had occasional tensions with foreign astronomy organisations like ESO, and there are a lot of telescopes in the Atacama Desert just because the skies are so good. The Europeans have put measures in place to try and make the relationship collaborative. As the host nation, Chile is allocated 10% of the operating hours on each ESO telescope. Bidding for telescope time is competitive,

So that allocation is good news for local astronomers. That has really helped to grow the astronomical community in Chile. I saw it like in my relatively brief or maybe not so brief period of seven years when I was working here. I could definitely see that the community was growing. The question of who gets to use these remarkable telescopes run by ESO is a live one for us here in Australia.

Our continent doesn't have any land that's high enough and cloudless enough to build one of these new generation mega telescopes. So we have to collaborate if we want to guarantee access for our astronomers. Now, we do have a stake in the giant Magellan telescope, the American-led proposal in the Atacama, if it gets fully funded and built.

But in terms of the ELT, the biggest of the lot and the only one with a sure path to completion, right now, we're not on the team sheet. We're kind of on the bench. I think that you'll find that most Australian astronomers would say that

Joining ESO is make or break for our field in this country. I called up Professor Matthew Collis from the ANU. He's worked a lot with ESO telescopes and just finished a six-year term as an Australian representative on its governing council. We've been incredibly fortunate up until now, and in fact we still are incredibly fortunate, in a country whose geographical advantages has until now made a very advantageous place to do astronomy.

It's radio quiet, so we're building the SKA. It has been a good place to do optical and infrared astronomy. But now we're beginning to push the limits. We have to think outside our own national boundaries. Aussie astronomers like Matthew have been using ESO telescopes, including the VLT, since 2017 as a strategic partner. This was a $70 million agreement between ESO and the Australian government with Australia.

with a strict expiry date. It's a trial run for us and for them over 10 years to see whether both sides are happy with the arrangement. In the middle of 2027, Australia has to decide whether it wants to join as a full member state or withdraw entirely. So it's an up or out situation. So as it stands, Australia won't have access to the world-beating giant telescope that I've just witnessed being built.

We'll also lose access to all ESO's other telescopes in Chile. But full membership of ESO doesn't come cheap.

The price tag is about $400 million, spread over the 10 years to 2037. It's not very different to the total amount being spent on Australian astronomy right now. That includes our current strategic partnership and our big telescopes, the Anglo-Australian Telescope and all the radio telescopes at PARC and the Australian SKA Pathfinder and all the rest.

So, yes, it would be an increase, but it would not be an enormous increase over what we're doing now. So you say that it's about the same. Does that mean if we added this membership on top, we'd be doubling the investment in astronomy? Yes, except, of course, that we would take away the money that we're currently spending on our strategic partnership and we would probably stop paying for the operations of the Anglo-Australian telescope. So there are savings as well.

So overall, it would be probably more like about a 50% increase in the amount that's being spent. So this is a big decision, a stake in the world's very best ground-based telescopes, possibly at the expense of maintaining smaller facilities on our own soil. Despite the excitement and support of many like Matthew Collis, some Australian astronomers have quietly expressed reservations about the price of ESO membership.

Meanwhile, the deadline is looming. To sign on from 2027, the federal government will need to start factoring the cost into budgets from 2025. I asked both Science Minister Ed Husic and Shadow Science Minister Paul Fletcher about joining ESO. Each pointed out their own party's previous commitments, but gave no indication about their support for ESO membership.

In terms of what we'd get for $40 million a year, Matthew Collis thinks it's a no-brainer, especially at the thought of Aussie science being done with the extremely large telescope. Here's our chance to be engaged with a project that will ring down the ages, that will actually make a difference and be remembered when everyone's GDP and who won the last election is long, long forgotten. What sort of things can we do with this instrument that we can't do with...

say, the James Webb, which I guess is currently taking the sharpest pictures we can see? So the ELT is going to do a lot of things that the James Webb simply cannot do. So the first thing to remember is that the Extremely Large Telescope, ELT, has a mirror which is 39 metres across.

And that means that it is collecting much, much more light than the James Webb Space Telescope, about 40 times as much light and about 15 times as much light as the biggest ground-based telescopes.

Moreover, because we're going to be using the latest adaptive optics technology to take the blurring of the atmosphere out of the equation... If you remember from earlier, that's the laser beams shining into the sky, igniting fake stars so the telescope can measure and subtract any pesky blurring or twinkling.

it will actually be able to take images which are five to six times sharper than those that the James Webb can take. And of course, James Webb has a finite lifetime. We hope it's a long lifetime, but, you know, it was designed for five years. It should easily make 10. We're hoping for 20, but the ELT should be around for at least 50. That's the typical time that most ground-based telescopes last. And...

Over that time, we will be able to upgrade all the instrumentation with the latest and greatest technology. So it will only get better and better over time, whereas James Webb is what it is. It can't improve. Yeah, we can't send a repair team out to the JWSC. If it gets hit by a micrometeorite, that's it, I'm afraid. Once the ELT is operational, that huge...

A huge light bucket of a mirror will mean it can look further out into space and so further back in time than ever before to study in detail the first galaxies that ever formed and the very first generation of stars which burned big and bright and died young well over 13 billion years ago.

It will also be sharp enough to look for rocky little planets like ours orbiting alien suns. For the first time, we should be able to directly detect Earth-like planets in Earth-like orbits around stars like our sun over a big volume of the nearby galaxy. And so hopefully we'll come up with a list of other Earth-like planets that we can try talking to and seeing if there's anybody home.

But beyond that, it should be able to look at their atmospheres. When they pass in front of a star, we will see the light from the star through their atmosphere. And that might tell us whether that atmosphere has oxygen in it, whether it has water in it, whether it even has industrial pollutants in it. And that will be fascinating as well. Finally, I ask Matthew something I've been wondering.

Why do we need to keep building bigger and shinier telescopes? Can't we just keep doing more science with the ones that we've already got? We can do more science, although after a while it's diminishing returns. Just like any particular tool you have, once you've done all the good things that you can do with it, you end up doing the same old things over and over again. Astronomy is all about discovering the universe.

And the way we discover more about the universe is to have more powerful tools for exploring the universe. And so every time we have a more powerful telescope, we have learned new things about the universe. There has never been a new telescope that went up and people said, "Well, that was boring, wasn't it?" It never happens that way. The universe is just full of surprises.

Speaking of surprises, back on a hill in the Chilean desert, inside the busy control room of the VLT, the current top of the range optical telescope, I met another Aussie. Hello, nice to meet you Jonathan. Nice to meet you too. Yeah, I was surprised to know that you were on the mountains. A PhD student from Sydney. So I'm Nicholas Borsado.

I'm affiliated with Macquarie University and Lund University and I'm a PhD student. What are you looking at tonight? So I'm looking at the transit of a sub-Neptune. Basically it's a planet that has a mass that's smaller than Neptune but larger than Earth and it's very, very close to its star. So it's orbiting around and these planets have some really interesting characteristics like they're known to evaporate and so I'm trying to capture that. And what is it like to be visiting this telescope?

Is it one night's observing? How many nights are you here? I'm just here for one night of observing. So it's pretty amazing. So when I started my bachelor's degree, I actually saw a picture of the ESO telescopes coming online and I immediately was like, this is my dream. I want to come here. And that was 10 years ago. So I put

put in my observing proposal and it got accepted and then I was just so excited and yeah, I've come here and it's pretty much everything I expected. It's like Disneyland for astronomers. You have everything you could want here and people here are all really interested in space and science as well which is really inspiring. And they're about to add a new ride to...

The Disneyland, right? Is the ELT something you might get to use or just excited about? So yes and yes. So it's going to be a few years yet. I will have graduated from my PhD, so I would have been more of a senior scientist, but

it's going to revolutionize what we understand about astronomy especially in terms of exoplanet atmospheres we may be even able to start looking at earth-sized planets and their atmospheres when we look at this these telescopes it's so large and so i guess you're among the australian astronomers who would very much like

Australia to be a member of ESO so that you can use the ELT? Very much so. My personal opinion is the future of Australian astronomy actually does ride on this. In terms of funding, ESO just has more power for us to make jumps in terms of our academic knowledge and scientific knowledge in this area. I think if Australia wasn't part of that, we would start to be left behind or

Most of our optical scientists would probably have to look for jobs somewhere else overseas just because we need facilities to do our work and yeah without that it's not possible.

Whether or not Nick and our next generation of homegrown astronomers will be joining those from Europe and from Chile here under the pristine skies of the Atacama, that's in the hands of the Science Minister and Cabinet. What will we see when the world's biggest eyeball finally opens and looks up? That's a chapter yet to be written. One thing's for sure.

The pictures will be amazing. That science show special from the Atacama Desert was presented by Jonathan Webb. He travelled to Chile by means of the European Southern Observatory. Production by Will Ockenden and David Fisher. Technical wizardry by Simon Branthwaite. Next week in this science show summer season, Jennifer Doudna and Merlin Crossley. A conversation to cherish. I'm Robin Williams.

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