Building giants

Three massive new telescopes will soon be giving us unprecedented images of space — and time

In the northern stretches of the Atacama region of the Andes, far above the world, a demolition team is planting explosives. In the windswept silence of the high desert, they meticulously connect a series of wires to charges buried in the thin, dry soil. The team are working atop a mountain peak called Cerro Armazones surrounded by terrain that looks much like Mars — made all the more alien by a series of metallic machines shimmering on the horizon. With their work completed, the team withdraws and takes cover. The harsh sun beats down relentlessly, the countdown reaches zero and the mountaintop explodes. It’s dramatic close up, but just a small puff of smoke seen from a distance amid the vast, open landscape. And ith this small step, construction of humanity’s largest-ever telescope is underway.

5000 cubic metres of rock being blasted away. Credit: European Southern Observatory (ESO)

Sited in the Atacama Desert of Chile, the European Extremely Large Telescope is one of three ambitious new Earth-based observatories currently in the works. Alongside the Giant Magellan Telescope further south in the Atacama and the Thirty Meter Telescope in Hawaii, it marks a significant leap forward in observing power — a momentous ‘next step’ for astronomy. Each telescope promises to not only revolutionise astronomy alone but fundamental physics, astrophysics, astrobiology, the search for life beyond our planet, our entire understanding of the universe and our place in it. Combined, the three instruments’ contribution to our understanding of the cosmos could be profound.

Far larger, more powerful and smarter than anything we currently have at our disposal, these ‘extremely large telescopes’ (or ‘super giant earth-based telescopes’ if you prefer — we do) represent a new era in astronomy. The larger mirror arrays of the E-ELT, GMT and TMT will gather exponentially more light than what’s currently possible — picking up dim and distant Space Stuff we can’t currently see. An array of high tech instruments and hyper-high-resolution cameras will capture this light and deliver unprecedented images — rivalling and surpassing those we’ve come to enjoy from the Hubble Space Telescope. A combination of smart sensors, precision control and complex software will virtually wipe away the dense atmosphere of our planet, giving us a crystal clear view out in space — and time. These new observatories will be so powerful that we’ll be able to look back to the very beginnings of our universe and watch as the first stars and galaxies began to form — in effect gazing back to the very birth of existence.

“It will revolutionise the way we understand the Universe,” explains Dr. Michele Cirasuolo, Programme Scientist of the European Extremely Large Telescope at ESO. “For example, one of the key open questions is to understand how the first stars and galaxies formed and how they evolved in time to create the systems we see today, like our Solar System and our Milky Way. As you can imagine these primeval distant objects are very faint and very dim, so getting any light from them is a huge challenge. We’re also limited by the properties of our own atmosphere.”

Detailed design for the E-ELT. Credit: ESO

“The E-ELT is going to radically change all of this because it comes with two massive upgrades. One is the giant mirror, so it’s able to collect significantly more light, and the other one is the telescope’s adaptive optics, which changes the shape of the mirror to compensate for turbulence in the atmosphere. That allows us to remove the blurring effect created by the atmosphere and obtain much sharper images — 15 times better than Hubble Space Telescope!”

It’s been a relatively short but incredible journey to reach this point — a story that begins far below the high-altitude Andes, in the low-lying Netherlands. It was there, in 1608, that Hans Lippershey created the world’s first telescope — a simple but revolutionary device. His breakthrough (although other inventors were working on similar ideas) was the combination of two glass lenses — one to gather light and the other to focus it on the human eye. With the Dutch War of Independence dragging interminably on, seeing an enemy’s troops movements from afar promised to transform warfare. Word of the invention soon spread. By the following summer, Italian polymath Galileo Galilei had heard of the telescope and set out to make his own. Working in Padua, he soon constructed his a vastly improved model and, curious about the moon, stars and planets, became the first person to aim it at the heavens.

Galileo’s sketches of the moon from Sidereus Nuncius

What he saw — and sketched — changed the world. Long-held theories and ideas, truths and certainties, dogma and gospel collapsed under the magnifying gaze of the telescope. Most obviously, even through Galileo’s early models, was the fact the Moon wasn’t a perfect, unblemished sphere as previously accepted, but a rocky, crater-pocked, mountainous land of its own: another world out in space. Nowadays it seems obvious, but imagine how revolutionary this was in 17th Century Europe.

Next and perhaps even more momentous were Galileo’s observations — and conclusions — about Jupiter’s moons. The giant planet’s four largest moons were (and remain) visible as four points of light when viewed through a small telescopes or even binoculars, and Galileo was able to observe them night after night. Watching and plotting their motions, Galileo came to realise they weren’t stars in the background but in fact moons of Jupiter. This mini Solar System demolished the notion that everything revolved around us, here on Earth, and was reinforced by his later discovery of the phases of Venus, caused by its rotation around the sun. These were humbling and momentous discoveries for mankind which put Galileo in conflict with the church, but eventually led to the acceptance of Nicolaus Copernicus’ assertion that Earth and the other planets revolved around the sun.

From its very beginning, then, the telescope has been an instrument of truth — a lens for uncovering the very nature of existence and why we’re here. Looking up at the stars was and remains not just ‘astronomy’, but a way of gazing into time and space, matter and energy. Like many technologies, it was improved on in small increments and giant leaps, perhaps the biggest coming with Isaac Newton. Instead of collecting light with a lens, which blurred and distorted the image beyond a certain size, Newton hit upon the idea of using a mirror to collect and reflect light — creating the first ‘reflecting telescope’ in 1668. From that point on, telescopes have continued to improve, moved beyond visible light into radio and X-ray frequencies and subdivided into thousands of variations, but one general rule remains the same: the bigger the better.

Artist’s rendering of the E-ELT at dusk. Credit: ESO

“We are contributing to something vast,” says Dr. Cirasuolo, “As Newton himself said, we’re standing on the shoulders of giants. A lot has been done before and we’re taking advantage of hundreds of years of telescope building. We went from small telescopes to very large ones in order, to be at the forefront of the astronomical research. It’s very exciting to be a pioneer — what we doing is being done for the first time in the history of humanity.”
 
Massive, immobile telescopes first appeared in the late 1700s and can now be found in isolated, high-altitude areas around the world — creating a surreal juxtaposition of clean, high technology nestled amid natural, often empty landscapes. In these remote, silent places, vast mirrors sweep the skies night after night, peering into the furthest reaches of our galaxy and beyond from the high mountains of the Pyrenees, the Caucasus and California to the distant Canary Islands off Africa, the volcanic peaks of Hawaii and the high deserts of Chile. The latter three provide the very best conditions on the planet for visible-light astronomy, thanks to their unique combinations of altitude, clear skies and location — being far away from artificial light sources and manmade pollution. When choosing the location for our next big leap in astronomy, the E-ELT and GMT planners opted for Chile over the Canary Islands, while scientists behind the TMT are hoping to build it in Hawaii.

The twin telescopes of the W. M. Keck Observatory atop Mauna Kea in Hawaii. Credit: Kevin Stanley

Planned for a sit near the top of the Mauna Kea volcano on Hawaii’s Big Island, the Thirty Meter Telescope will be three times as wide with nine times more area than the largest existing visible-light telescope in the world. Like the E-ELT, it will use hexagonal, segmented mirrors — a technology first pioneered on the nearby twin Keck telescopes. Mauna Kea is the highest island mountain in the world, and the observatory will be located above about 40 percent of the planet’s atmosphere. The climate up there is very stable, dry, and cold — with the added bonus of a very predictable atmosphere due to the area’s winds. Though ten metres smaller than the E-ELT, the TMT represents a massive step forward, and with two giant telescopes at different latitudes astronomers will get unparalleled views both ‘out’ and ‘down’ into space.

“The Universe is unimaginably vast and most objects in it are very faint and have very small apparent sizes,” says Dr. Michael Bolte, Professor of Astronomy at the University of California Santa Cruz and member of the TMT International Observatory Board. “For this reason, our knowledge of the Universe has been strongly driven by ever more powerful telescopes and instruments. With each step forward in telescope size and capability we have learned new, unexpected things about the nature and physical history of the Universe. It’s really exciting and humbling to play a role in this human endeavour.”

A model of the Giant Magellan Telescope

Meanwhile, the Giant Magellan Telescope will likely be the first of this new generation of observatories to open its giant eyes — and they’re a little different. Instead of hundreds of smaller mirrors, the GMT will have just seven but they’ll be massive. While not as big as the E-ELT, it will still require a dome 22 stories high to house it. Each of the circular 8.4-meter diameter segments will weigh about 20 tons, and when combined they’ll give the telescope ten times the resolution of the Hubble Space Telescope.

“The primary mirror array has a particularly ‘fast’ focal ratio,” explains Dr. Patrick McCarthy, Interim President of Giant Magellan Telescope Organisation, “which allows us to build spectrographs with high spectral resolution. This is particularly important when studying the structure and chemistry in nearby galaxies. This week we’re hosting a conference called ‘Resolving Galaxies in the Era of Extremely Large Telescopes’ focused on this topic — understanding what nearby galaxies can tell us about conditions in the early universe when they formed, and the forces that drive their evolution today. The GMT will be well suited to addressing these questions.”

Far from ‘competing’ with each other, scientists and planners working on all three projects see co-operation as vital. The E-ELT is being built by a coalition of 16 mostly European countries, the TMT by China, Japan, Canada, India and the USA while the GMT will be funded and used by research groups and universities from Australia, the US, Korea, Brazil. Each observatory will cost between a billion and 1.5 billion US dollars to build, and upwards of $50 million a year to operate thereafter — so projects like this go well beyond international borders. If a billion dollars sounds like a lot to spend on astronomy, consider that the EU spends 250 times that amount every year on defence. Like space exploration, particle physics and other big science projects, massive telescopes force us to work together if we want to see farther, push beyond and discover more. There’s something profoundly optimistic about the way that the most pressing questions in science bring us together — to move forwards as a species, we need to act as a single species.

“We have excellent collaboration with the TMT,” says E-ELT Programme Manager Roberto Tamai on the technical aspects of this co-operation. “There are lots of similarities with their system. The mirror segments are a very similar size and we are exchanging knowledge about the sensors, lasers and controlling the phasing.”

Modern astronomy often requires multiple telescopes to fully exploit a discovery

“Modern astronomy often requires multiple telescopes to fully exploit a discovery,” adds Dr. McCarthy. “All three ELTs represent dramatic advances over currently existing telescopes and the different strengths of these telescopes mean that there are opportunities to work together efficiently. Astronomers will very likely use the GMT, TMT and E-ELT to perform detailed follow-up work on observations made by other telescopes, such as the Large Synoptic Survey Telescope. The GMT will also complement the James Webb Space Telescope by helping to obtain sharper images of exoplanets, faint galaxies and other objects that the space-based instrument discovers.”

Working together, a key target for all three telescopes will be exoplanets — worlds orbiting distant suns. The past decade has seen incredible advances and discoveries in this field, which, thanks to the near certainty of finding ‘another Earth’ has captured the world’s imagination more than perhaps any other aspect of modern astronomy. Thanks to space-based telescopes like Kepler and ground-based instruments like HARPS and WASP, we now know that most stars have planets around them and that Earth-sized planets in the ‘habitable zones’ of their host stars are common. Scientists believe there could be 40 billion such worlds in the Milky Way alone.

Artist’s impression of Kepler-452b. Credit: NASA Ames/JPL-Caltech/T. Pyle

In January this year, researchers announced the discovery of Kepler-438b, a very Earth-like planet orbiting a red dwarf star in the constellation Lyra. Then in July, NASA announced an even more exciting world: Kepler-452b. This marks the first potentially rocky Earth-like planet discovered in the habitable zone of a star very similar to our Sun, meaning life there could be much like Earth. While currently technology allows us to detect these kinds of planets through various (very clever) methods, the next generation of telescope will allow us to actually see them.

“Space-based and existing ground-based telescopes can just barely begin to characterise the highest mass, highest temperature exoplanets”, explains Dr. Bolte, referring to the larger exoplanets like hot-Jupiters and lava planets, which are are very different from the main population of planets. “The new generation of telescopes will allow us to study the main population and to answer the important question whether terrestrial exoplanets have atmospheres similar to Earth’s. The study of the atmospheres of earth-like exoplanets can go further by looking for the existence of water and organic molecules, evidence of biological activity, and evidence of extra-terrestrial life in the molecules present in the atmosphere.”
 
 In other words, we’ll be looking for life itself through these telescopes by studying the atmospheres of distant worlds. Bearing in mind we’re only just over 400 years from the point Galileo first raised his prototype to the sky, this is a momentous achievement. Gazing up at the miniature worlds in orbit around Jupiter, Galileo would never have dreamed that we’d be studying the skies of far more distant ones just four centuries later. Other targets for the Big Three include the investigation of Dark Matter and Dark Energy — the still-mysterious elements of the Universe that we’ve only just barely begun to explore. We’ll also be able to look more closely at the supermassive black holes now known to exist at the hear of most galaxies, including our own.

A ghostly ring of dark matter (represented in blue) in the galaxy cluster CL 0024+17. Credit: NASA, ESA, M.J. Jee and H. Ford (Johns Hopkins University)

“It’s nearly infinite,” says Dr. Cirasuolo of the E-ELT’s potential contribution to science. “We’ll have a new facility that works for everything: planets, galaxies, black holes, stars, dark matter, physics — the amount of science we can do is enormous. At the moment we can detect exoplanets, but for most of them we can’t measure their atmosphere. We’re limited to some of the larger, Jupiter-like planets but we really want to look for more Earth-like planets, which we’ll be able to do. If you want to study the centre of our own galaxy and the supermassive black hole we know is in there, today’s telescopes can’t get close to that black hole. There are a lot of stars in there and it’s easy to get confused, but with the E-ELT we’ll be able to get very sharp images and see if the gravitational field that Einstein predicted works, or if it doesn’t. So you can study physics, you can study stars, how stars build up into galaxies, how galaxies evolve over time. We can study how supernovae explode, and the physics of that. It’s just such a fantastic observatory across the entire board — everything we can think of now and probably some uses we haven’t thought of yet.”

We’ll have a new facility that works for everything: planets, galaxies, black holes, stars, dark matter, physics — the amount of science we can do is enormous

At all three observatories, ‘adaptive optics’ will be key to the telescopes’ success. As Dr. Cirasuolo explains, most current instruments use what’s called ‘active’ optics to partially counter the effects of the Earth’s atmosphere by changing every few minutes to compensate for turbulence in the hazy shroud which surrounds and protects our planet. The new generation of advanced ‘adaptive’ optics will be a step change, using lasers to continually measure the effects of the atmosphere and instantly compensate.

“The atmosphere is quite complicated,” he says, “You have stratification — different layers of air that each behave differently — but the telescope is able to see that and calculate around it. It practically removes the atmosphere; like you’re in space. This is an enormous technological advance — you need very fast sensors, very accurate sensors, very good cameras, very fast computers and very good algorithms. You have 5000 actuators moving to a nanometre accuracy to change 3000 tons of steel and mirrors. It’s very very challenging — so what we’ve done is built some prototypes to demonstrate that this technology is feasible.”

Instead of merely acting as one giant mirror, which of course it will do, the E-ELT’s technology will transform it into a shimmering mass, constantly shifting and adapting to Earth’s turbulent atmosphere, working as one to reveal extraordinary detail. For astronomers, the development of this advanced new technology coincides nicely with a decline in space launch technology. Floating clear of the Earth’s atmosphere, space telescopes permit longer observing time, as day and night are not the same in orbit as on the ground. They also collect energy from the entire electromagnetic spectrum and not just the portion that passes through the Earth’s atmosphere, but following the retirement of NASA’s space shuttle, servicing them is nigh-on impossible. Using the shuttle, Hubble got four repair missions over its lifetime, something that — paradoxically — would be impossible today.

The James Webb Space Telescope features a 6.5m mirror array and is due to launch in 2018. Credit: NASA

“You can’t put a 40-metre telescope in space,” explains Dr. Cirasuolo, “That’s impossible — at least for the next 100–200 years, right? So what you do is put the biggest you can: Hubble is two and a half metres and the James Webb Space Telescope is going to be six and a half metres. At the moment that’s our limit, and it’s very very expensive. Everything has to be tested hundreds of times because if something breaks you’re screwed. It will be placed so far out in space you can’t go and repair it. On the ground yes we have the atmosphere to worry about, but we can build much larger and if someone goes wrong we can fix it. We can afford some failures.”

Although easier than maintaining a telescope out in space, keeping all three extremely large telescopes working smoothly will be an extremely large challenge. The sheer scale and complexity of each instrument is mind-boggling — with CGI people appearing tiny beside them in artists’ renderings. The E-ELT’s total mirror surface, for example, is the size of two basketball courts combined, and the dome needed to house it is 100 meters across — about the size of the Colosseum in Rome.

The E-ELT’s dome will be about the size of the Colosseum in Rome, but built atop a remote 3000-metre mountaintop. The existing VLT telescope is in the middle. Credit: ESO

“One challenge with any project is the people — keeping different teams in different parts of the world working together,” explains E-ELT Programme Manager Roberto Tamai. “Another is size. It’s the Formula 1 of telescopes — the cutting edge. Everything is being done for the first time. Bringing it to life every single sunset, every evening, will be a challenge.”

It’s the Formula 1 of telescopes — the cutting edge. Everything is being done for the first time.

Like the similarly-designed TMT, the remote telescope will need a higher level of maintenance than previous telescopes — and it will need to be done in-house, way out in the Atacama desert. The E-ELT will be composed of 798 mirrors, two of which will be removed and cleaned every morning after the night’s observations have finished. This is mostly for dust, the very rare rain that falls in the desert and, as Tamai laughs “there are a few birds — I’m sure you understand the implication.” Running the E-ELT will be a 24 hour a day operation, with daytime spent on maintenance and nights spent observing — every single second of which will be ultra-precious and often booked months in advance, if not years, by astronomers lucky enough to get time to use the telescope. In other words, nothing can go wrong.

“We have 798 segments, each with twelve edge sensors and each with three actuators and warping harnesses,” says Tamai. “So that means lots of maintenance, correction, realignment, calibration. Then there’s refilling of liquid nitrogen for the instruments detectors, maintaining the doors and louvres of the dome, checking oil levels — just like a car. The chain of events to maintain it will be like being in a factory.”

Once these three exploration factories are in full swing, new discoveries will inevitably start to flow in. One astonishing image taken by the Hubble Space Telescope, for instance, shows light bending and warping under the gravitational influence of dark matter and the trillions of stars within the Abell 1689 galaxy cluster. The E-ELT’s predecessor, the Very Large Telescope, discovered R136a1: a star twice as big as previously thought possible. And another famous unexpected discovery was made after researchers cleaned every part of a radio telescope — including pigeon droppings — to eliminate the source of a mysterious, steady noise. This turned out to be the ‘Cosmic Microwave Background’ — radiation left over from the Big Bang. While astronomers are already working on key areas they know they’ll want to study, intriguingly it’s these unknown and unexpected discoveries that may stand as their greatest discoveries, and spur even grander designs.

Radio astronomer Robert Wilson co-discovered the remnants of the Big Bang while working on an unrelated project. “The thing we (saw) was much more important than what we were looking for. This was really the start of modern cosmology.”

“The E-ELT will answer a lot of questions, and trigger new ones,” says Dr. Cirasuolo. “It’s a very big jump — we’ve gone from ten to nearly forty metres! The next jump will be to 100m, because as great as the E-ELT will be there will always be new discoveries to make. So maybe in 2040 or 2050, with new technology to make telescopes even better, we’ll build something to look at other wavelengths: x-rays, radio. There’s still a lot to be done.”

“As the limits to exploration are reached, even larger telescopes will be built,” agrees Dr. Bolte. “It’s possible to imagine a future with ever-larger telescopes in space or even on the Moon.”

For now, we’re getting very close to seeing something inconceivable in the time of Lippershey and Galileo: seeing the very beginnings of the known Universe. With this next generation of telescopes, we’ll be able to pick out the most remote objects yet seen. Because of the mind-bogglingly vast distances involved, imaging these distant stars and galaxies means we’re looking back in time, or as Dr. Cirasuolo puts it more poetically, “gazing back 13 billion years across the redshift” — the change in wavelength due to distance and the expansion of the Universe. So could we ever see the beginning of time itself?

“The beginning of time is difficult,” he admits, “but the beginning of star formation yes. The closer you get to the Big Bang the hotter and hotter the universe, so at some point you don’t have objects like planets and stars — you only have energy. You can see only particles; it’s a different type of physics. However, with the next generation of telescopes we can explore more than 13 billion years of the history of the universe, to understand the formation of stars and galaxies, up to the very first objects less than a few hundred million years after the Big Bang.”

Lying at the very edge of what we can currently see, GN-z11 (enlarged above) is currently the oldest and most distant known galaxy in the observable universe. Credit: Hubble

For now, these dreams are years away yet. The GMT should be operational by 2021, with the E-ELT following a few years later in 2024. The TMT, meanwhile, is facing opposition from some native Hawaiian groups, who see the top of Mauna Kea as a sacred place that is meant to be off-limits. Protests have recently blocked construction, but the organisation is in dialogue with various parties and hopes to proceed as planned and see first light in 2022. Back atop Cerro Armazonas, the work goes on, as the desert awaits its newest alien artefact.

“After living there, I remember this burst of green and blue after returning to sea level,” remembers Roberto Tamai. “The desert all around looks like a place where God was uncertain what colour of pink to use. Each mountain has a different pink/brown shade, it’s like when you paint a test strip. Stopping at night and raising your eyes towards the sky is just an unbelievable feeling. You can work in the dark with just the light of the distant stars to guide you.”


This article was originally published in the fourth issue of Berlin Quarterly, available for purchase here.

For more science and space content by the author and other contributors, please visit www.super-collider.com