Earliest Black Hole Gives Rare Glimpse of Ancient Universe

Astronomers have at least two gnawing questions about the first billion years of the universe, an era steeped in literal fog and figurative mystery. They want to know what burned the fog away: stars, supermassive black holes, or both in tandem? And how did those behemoth black holes grow so big in so little time?

Quanta Magazine


Original story reprinted with permission from Quanta Magazine, an editorially independent publication of the Simons Foundation whose mission is to enhance public understanding of science by covering research developments and trends in mathematics and the physical and life sciences.

Now the discovery of a supermassive black hole smack in the middle of this period is helping astronomers resolve both questions. “It’s a dream come true that all of these data are coming along,” said Avi Loeb, the chair of the astronomy department at Harvard University.

The black hole, announced Wednesday in the journal Nature, is the most distant ever found. It dates back to 690 million years after the Big Bang. Analysis of this object reveals that reionization, the process that defogged the universe like a hair dryer on a steamy bathroom mirror, was about half complete at that time. The researchers also show that the black hole already weighed a hard-to-explain 780 million times the mass of the sun.

A team led by Eduardo Bañados, an astronomer at the Carnegie Institution for Science in Pasadena, found the new black hole by searching through old data for objects with the right color to be ultradistant quasars—the visible signatures of supermassive black holes swallowing gas. The team went through a preliminary list of candidates, observing each in turn with a powerful telescope at Las Campanas Observatory in Chile. On March 9, Bañados observed a faint dot in the southern sky for just 10 minutes. A glance at the raw, unprocessed data confirmed it was a quasar—not a nearer object masquerading as one—and that it was perhaps the oldest ever found. “That night I couldn’t even sleep,” he said.

Eduardo Bañados at the Las Campanas Observatory in Chile, where the new quasar was discovered.
Courtesy of Eduardo Bañados

The new black hole’s mass, calculated after more observations, adds to an existing problem. Black holes grow when cosmic matter falls into them. But this process generates light and heat. At some point, the radiation released by material as it falls into the black hole carries out so much momentum that it blocks new gas from falling in and disrupts the flow. This tug-of-war creates an effective speed limit for black hole growth called the Eddington rate. If this black hole began as a star-size object and grew as fast as theoretically possible, it couldn’t have reached its estimated mass in time.

Other quasars share this kind of precocious heaviness, too. The second-farthest one known, reported on in 2011, tipped the scales at an estimated 2 billion solar masses after 770 million years of cosmic time.

These objects are too young to be so massive. “They’re rare, but they’re very much there, and we need to figure out how they form,” said Priyamvada Natarajan, an astrophysicist at Yale University who was not part of the research team. Theorists have spent years learning how to bulk up a black hole in computer models, she said. Recent work suggests that these black holes could have gone through episodic growth spurts during which they devoured gas well over the Eddington rate.

Bañados and colleagues explored another possibility: If you start at the new black hole’s current mass and rewind the tape, sucking away matter at the Eddington rate until you approach the Big Bang, you see it must have initially formed as an object heavier than 1,000 times the mass of the sun. In this approach, collapsing clouds in the early universe gave birth to overgrown baby black holes that weighed thousands or tens of thousands of solar masses. Yet this scenario requires exceptional conditions that would have allowed gas clouds to condense all together into a single object instead of splintering into many stars, as is typically the case.

Cosmic Dark Ages

Even earlier in the early universe, before any stars or black holes existed, the chaotic scramble of naked protons and electrons came together to make hydrogen atoms. These neutral atoms then absorbed the bright ultraviolet light coming from the first stars. After hundreds of millions of years, young stars or quasars emitted enough light to strip the electrons back off these atoms, dissipating the cosmic fog like mist at dawn.

Lucy Reading-Ikkanda/Quanta Magazine

Astronomers have known that reionization was largely complete by around a billion years after the Big Bang. At that time, only traces of neutral hydrogen remained. But the gas around the newly discovered quasar is about half neutral, half ionized, which indicates that, at least in this part of the universe, reionization was only half finished. “This is super interesting, to really map the epoch of reionization,” said Volker Bromm, an astrophysicist at the University of Texas.

When the light sources that powered reionization first switched on, they must have carved out the opaque cosmos like Swiss cheese. But what these sources were, when it happened, and how patchy or homogeneous the process was are all debated. The new quasar shows that reionization took place relatively late. That scenario squares with what the known population of early galaxies and their stars could have done, without requiring astronomers to hunt for even earlier sources to accomplish it quicker, said study coauthor Bram Venemans of the Max Planck Institute for Astronomy in Heidelberg.

More data points may be on the way. For radio astronomers, who are gearing up to search for emissions from the neutral hydrogen itself, this discovery shows that they are looking in the right time period. “The good news is that there will be neutral hydrogen for them to see,” said Loeb. “We were not sure about that.”

The team also hopes to identify more quasars that date back to the same time period but in different parts of the early universe. Bañados believes that there are between 20 and 100 such very distant, very bright objects across the entire sky. The current discovery comes from his team’s searches in the southern sky; next year, they plan to begin searching in the northern sky as well.

“Let’s hope that pans out,” said Bromm. For years, he said, the baton has been handed off between different classes of objects that seem to give the best glimpses at early cosmic time, with recent attention often going to faraway galaxies or fleeting gamma-ray bursts. “People had almost given up on quasars,” he said.

Original story reprinted with permission from Quanta Magazine, an editorially independent publication of the Simons Foundation whose mission is to enhance public understanding of science by covering research developments and trends in mathematics and the physical and life sciences.

Read more: https://www.wired.com/story/earliest-black-hole-gives-rare-glimpse-of-ancient-universe/

A Hidden Supercluster Could Solve the Mystery of the Milky Way

Glance at the night sky from a clear vantage point, and the thick band of the Milky Way will slash across the sky. But the stars and dust that paint our galaxy’s disk are an unwelcome sight to astronomers who study all the galaxies that lie beyond our own. It’s like a thick stripe of fog across a windshield, a blur that renders our knowledge of the greater universe incomplete. Astronomers call it the Zone of Avoidance.

Quanta Magazine


Original story reprinted with permission from Quanta Magazine, an editorially independent publication of the Simons Foundation whose mission is to enhance public understanding of science by covering research developments and trends in mathematics and the physical and life sciences.

Renée Kraan-Korteweg has spent her career trying to uncover what lies beyond the zone. She first caught a whiff of something spectacular in the background when, in the 1980s, she found hints of a potential cluster of objects on old photographic survey plates. Over the next few decades, the hints of a large-scale structure kept coming.

Late last year, Kraan-Korteweg and colleagues announced that they had discovered an enormous cosmic structure: a “supercluster” of thousands upon thousands of galaxies. The collection spans 300 million light years, stretching both above and below the galactic plane like an ogre hiding behind a lamppost. The astronomers call it the Vela Supercluster, for its approximate position around the constellation Vela.

Renée Kraan-Korteweg, an astronomer at the University of Cape Town, has spent decades trying to peer through the Zone of Avoidance.
University of Cape Town

Milky Way Movers

The Milky Way, just like every galaxy in the cosmos, moves. While everything in the universe is constantly moving because the universe itself is expanding, since the 1970s astronomers have known of an additional motion, called peculiar velocity. This is a different sort of flow that we seem to be caught in. The Local Group of galaxies—a collection that includes the Milky Way, Andromeda and a few dozen smaller galactic companions—moves at about 600 kilometers per second with respect to the leftover radiation from the Big Bang.

Over the past few decades, astronomers have tallied up all the things that could be pulling and pushing on the Local Group — nearby galaxy clusters, superclusters, walls of clusters and cosmic voids that exert a non-negligible gravitational pull on our own neighborhood.

The biggest tugboat is the Shapley Supercluster, a behemoth of 50 million billion solar masses that resides about 500 million light years away from Earth (and not too far away in the sky from the Vela Supercluster). It accounts for between a quarter and half of the Local Group’s peculiar velocity.

The Milky Way as seen by the Gaia satellite shows the dark clouds of dust that obscure the view of galaxies in the universe beyond.

The remaining motion can’t be accounted for by structures astronomers have already found. So astronomers keep looking farther out into the universe, tallying increasingly distant objects that contribute to the net gravitational pull on the Milky Way. Gravitational pull decreases with increasing distance, but the effect is partly offset by the increasing size of these structures. “As the maps have gone outward,” said Mike Hudson, a cosmologist at the University of Waterloo in Canada, “people continue to identify bigger and bigger things at the edge of the survey. We’re looking out farther, but there’s always a bigger mountain just out of sight.” So far astronomers have only been able to account for about 450 to 500 kilometers per second of the Local Group’s motion.

Astronomers still haven’t fully scoured the Zone of Avoidance to those same depths, however. And the Vela Supercluster discovery shows that something big can be out there, just out of reach.

In February 2014, Kraan-Korteweg and Michelle Cluver, an astronomer at the University of Western Cape in South Africa, set out to map the Vela Supercluster over a six-night observing run at the Anglo-Australian Telescope in Australia. Kraan-Korteweg, of the University of Cape Town, knew where the gas and dust in the Zone of Avoidance was thickest; she targeted individual spots where they had the best chance of seeing through the zone. The goal was to create a “skeleton,” as she calls it, of the structure. Cluver, who had prior experience with the instrument, would read off the distances to individual galaxies.

That project allowed them to conclude that the Vela Supercluster is real, and that it extends 20 by 25 degrees across the sky. But they still don’t understand what’s going on in the core of the supercluster. “We see walls crossing the Zone of Avoidance, but where they cross, we don’t have data at the moment because of the dust,” Kraan-Korteweg said. How are those walls interacting? Have they started to merge? Is there a denser core, hidden by the Milky Way’s glow?

And most important, what is the Vela’s Supercluster’s mass? After all, it is mass that governs the pull of gravity, the buildup of structure.

How to See Through the Haze

While the Zone’s dust and stars block out light in optical and infrared wavelengths, radio waves can pierce through the region. With that in mind, Kraan-Korteweg has a plan to use a type of cosmic radio beacon to map out everything behind the thickest parts of the Zone of Avoidance.

The plan hinges on hydrogen, the simplest and most abundant gas in the universe. Atomic hydrogen is made of a single proton and an electron. Both the proton and the electron have a quantum property called spin, which can be thought of as a little arrow attached to each particle. In hydrogen, these spins can line up parallel to each other, with both pointing in the same direction, or antiparallel, pointing in opposite directions. Occasionally a spin will flip—a parallel atom will switch to antiparallel. When this happens, the atom will release a photon of light with a particular wavelength.

One of the 64 antenna dishes that will make up the MeerKAT telescope in South Africa.
SKA South Africa

The likelihood of one hydrogen atom’s emitting this radio wave is low, but gather a lot of neutral hydrogen gas together, and the chance of detecting it increases. Luckily for Kraan-Korteweg and her colleagues, many of Vela’s member galaxies have a lot of this gas.

During that 2014 observing session, she and Cluver saw indications that many of their identified galaxies host young stars. “And if you have young stars, it means they recently formed, it means there’s gas,” Kraan-Korteweg said, because gas is the raw material that makes stars.

The Milky Way has some of this hydrogen, too—another foreground haze to interfere with observations. But the expansion of the universe can be used to identify hydrogen coming from the Vela structure. As the universe expands, it pulls away galaxies that lie outside our Local Group and shifts the radio light toward the red end of the spectrum. “Those emission lines separate, so you can pick them out,” said Thomas Jarrett, an astronomer at the University of Cape Town and part of the Vela Supercluster discovery team.

While Kraan-Korteweg’s work over her career has dug up some 5,000 galaxies in the Vela Supercluster, she is confident that a sensitive enough radio survey of this neutral hydrogen gas will triple that number and reveal structures that lie behind the densest part of the Milky Way’s disk.

That’s where the MeerKAT radio telescope enters the picture. Located near the small desert town of Carnarvon, South Africa, the instrument will be more sensitive than any radio telescope on Earth. Its 64th and final antenna dish was installed in October, although some dishes still need to be linked together and tested. A half array of 32 dishes should be operating by the end of this year, with the full array following early next year.

Kraan-Korteweg has been pushing over the past year for observing time in this half-array stage, but if she isn’t awarded her requested 200 hours, she’s hoping for 50 hours on the full array. Both options provide the same sensitivity, which she and her colleagues need to detect the radio signals of neutral hydrogen in thousands of individual galaxies hundreds of light years away. Armed with that data, they’ll be able to map what the full structure actually looks like.

Cosmic Basins

Hélène Courtois, an astronomer at the University of Lyon, is taking a different approach to mapping Vela. She makes maps of the universe that she compares to watersheds, or basins. In certain areas of the sky, galaxies migrate toward a common point, just as all the rain in a watershed flows into a single lake or stream. She and her colleagues look for the boundaries, the tipping points of where matter flows toward one basin or another.

Hélène Courtois, an astronomer at the University of Lyon, maps cosmic structure by examining the flow of galaxies.
Eric Leroux, University Lyon Claude Bernard Lyon 1.

A few years ago, Courtois and colleagues used this method to attempt to define our local large-scale structure, which they call Laniakea. The emphasis on defining is important, Courtois explains, because while we have definitions of galaxies and galaxy clusters, there’s no commonly agreed-upon definition for larger-scale structures in the universe such as superclusters and walls.

Part of the problem is that there just aren’t enough superclusters to arrive at a statistically rigorous definition. We can list the ones we know about, but as aggregate structures filled with thousands of galaxies, superclusters show an unknown amount of variation.

Now Courtois and colleagues are turning their attention farther out. “Vela is the most intriguing,” Courtois said. “I want to try to measure the basin of attraction, the boundary, the frontier of Vela.” She is using her own data to find the flows that move toward Vela, and from that she can infer how much mass is pulling on those flows. By comparing those flow lines to Kraan-Korteweg’s map showing where the galaxies physically cluster together, they can try to address how dense of a supercluster Vela is and how far it extends. “The two methods are totally complementary,” Courtois added.

The two astronomers are now collaborating on a map of Vela. When it’s complete, the astronomers hope that they can use it to nail down Vela’s mass, and thus the puzzle of the remaining piece of the Local Group’s motion—“that discrepancy that has been haunting us for 25 years,” Kraan-Korteweg said. And even if the supercluster isn’t responsible for that remaining motion, collecting signals through the Zone of Avoidance from whatever is back there will help resolve our place in the universe.

Original story reprinted with permission from Quanta Magazine, an editorially independent publication of the Simons Foundation whose mission is to enhance public understanding of science by covering research developments and trends in mathematics and the physical and life sciences.

Read more: https://www.wired.com/story/a-hidden-supercluster-could-solve-the-mystery-of-the-milky-way/

Deserts and dynamite: my journey to the cosmic heart of land art

As new film Troublemakers explores the extremes of land art, from lightning fields to satanic jetties, Alex Needham braves rattlesnakes to visit a desert observatory that lets you travel 26,000 years in time

Somewhere in the deserts of New Mexico, a nail is embedded into a type of flat-topped mountain known as a mesa. The positioning of this nail, shielded from the elements by a tin can, took days of trial and error, with astronomical measurements provided by the US Naval Observatory and the help of a surveyor. Finally, the correct spot was located: exactly in alignment with the axis of the Earth from the south pole to the north.

This nail which I braved rattlesnakes to find, on a mountaintop strewn with slabs of granite was fundamental to the success of Star Axis, an extraordinary naked-eye observatory that is the brainchild of artist Charles Ross. Only when Ross was sure he had the orientation precisely correct could he begin to build the structure he had dreamed about an obsession that has consumed him since 1971.

Star Axis is one of the worlds defining earthworks, otherwise known as land art. In the late 60s, a generation of young, New York-based artists, inspired by the space race but also by the turmoil of Vietnam, decided that galleries werent big enough to house their visions. So they struck out, choosing instead to make works on an epic scale, sculpted from the elements, in the astounding desert landscapes of the US south-west.

The power and the glory The Lightning Field by Walter de Maria

The results some of which could only be viewed properly from a plane include Robert Smithsons Spiral Jetty, a swirling basalt outcrop surrounded (before Utah was struck by drought) with vivid red water. This, says Virginia Dwan, the land art patron whose gallery helped facilitate it, makes the work feel almost satanic. Walter de Marias Lightning Field, meanwhile, features 400 stainless steel rods arranged in a grid in an area of high desert in New Mexico known for its electrical storms. Their appearance, during lightning flashes, is as dazzling as it is unearthly.

No less impressive is Michael Heizers Double Negative. Displacing 218,000 tonnes of rock, Heizer cut two enormous grooves 1,500ft (457 metres) long into a mesa in the Nevada desert. He followed this with City, also in the Nevada desert. Stretching over a mile, City is a staggeringly ambitious work full of sculpted pits and peaks. Heizer started it in 1972 and last year told the Guardian it was 98% finished.

Pretty little watercolours these are not. Made by bulldozers and dynamite instead of a paintbrush and easel, the works often sited on baking sandscapes fuse minimalism and modern industrial aesthetics to evoke the otherworldly structures of ancient civilisations, from Stonehenge to Mayan temples and the Egyptian pyramids.

Satanic Robert Smithsons Spiral Jetty, seen from the air

The desert is a metaphor for fate anything can happen there, says James Crump, director of Troublemakers, a gripping new documentary film about these land artists. Theres danger, but theres also this possibility of enlightenment. The deserts like space. When Heizer refused to participate in Troublemakers, Crump contemplated filming City with a drone. But such is Heizers gritty cowboy demeanour, he would have probably shot the drone down.

The works were often undertaken at great risk to the artists themselves: Smithson was killed in a plane crash in 1973 while surveying sites for new work Amarillo Ramp. You have to ask yourself which young artist is willing to go out and make work in these kinds of conditions, says Crump, and challenge themselves with the possibility of death?

Too large to be bought, sold or moved, these works can only be seen if youre willing to travel. But be warned: the desert terrain can be hostile, and the works are not always easy to locate. British artist Tacita Dean made a work about failing to find Spiral Jetty on her first visit in 1997. These days, she says regretfully, its signposted. Spiral Jetty, she told the Canadian Art Foundation last year, was very much about relating to some sort of hidden place beneath Great Salt Lake, the universal core. She called her visit a true pilgrimage. And like any pilgrimage, the journey is an integral part of the experience.

Gritty cowboy the building of Michael Heizers Double Negative

Which brings us to the extraordinary experience of seeing Star Axis. Like City, the work is still not finished one reason its not yet open to the public. The other is that the site has its perils, including several places where the unwary visitor could take a serious fall. Some railings will, apparently, be installed this summer. According to Crump, Ross himself once toppled off one of the structures high points while holding an 80lb bag of cement. Theres an element of sacrificial danger to his piece, says the film-maker.

The site is not suitable for daytrippers, which is why Ross has asked me not to divulge its exact location. When Star Axis finally opens which Ross estimates will be three to four years from now (though one associate says hes been saying that for the past 20 years) six people will be admitted at a time, staying in a guesthouse down the hill so they can experience Star Axis by day and night.

Ross spent four years looking for this site. Then one day he was parked in the New Mexico desert with no one for miles around when a cowboy came riding up like the Marlboro Man. Ross explained that he was looking for land for a project and the cowboy said: Oh, my dad would be interested in that. He gave him a business card.

Under construction Spiral Jetty

Ross called the number and spoke to rancher WO Culbertson who, much to his surprise, said that his proposed observatory sounds like just the kind of thing we need around here. How much land did he need? About a square mile. Well hell, we got plenty of those, declared Culbertson. Drive around the ranch and pick one out. Ross took 400 acres in the end 50 for Star Axis and 350 for the mesa on which his house is situated, which he shares with his wife, the artist Jill OBryan.

My friend Jess and I have driven through mountains and deserts to a prearranged meeting point: a postbox on a dirt road. Were early, so we drive down the road. Off in the distance we can see a stony point sticking out of the top of a mesa. Ominous and alluring, this is our first sight of Star Axis.

At 5pm, a man called Harry Leippe arrives in a pickup truck. A sculptor based in New Mexico, Leippe is 90, and has known Ross, his junior by 12 years, since the late 1950s, when both were at Berkley, where Ross was studying mathematics. Leippe has collaborated on Star Axis since before the beginning, and looks after the site while Ross is away: the artist spends half the year here, the other half in New York.

Its not difficult to see why Star Axis is taking so long. Despite the monumental scale of the project, it is being built by a surprisingly small number of people: between four and six locals. A greater number than that, says Ross, and people start to get in each others way. Do people round here think hes nuts? My foreman overheard someone in the general store say, Hey man, that guy up on the hill, hes crazier than we are! A reputation Id like to keep.

Leippe leads us down five miles of dirt road. We go through two gates warning away trespassers and bumpily ascend the mesa. At the top is a granite pyramid, glowing pinkish in the late afternoon. Much of the granite was donated by a company in Texas: Ross estimates its value at a million dollars. When I ask if the project has been easy to fund, he shouts with laughter. My god, no! Were still struggling to get funding and I dont have the money to finish it. But weve had some generous donors and Ive funded more than half through sales of my work. Rosss other pieces include prism installations, which he started making in 1965. Exploring light has been his lifes work.

Inside the Hour Chamber at Star Axis, with the north star visible at the top of the triangular opening

Inside the pyramid, a curving flight of steps leads to the Hour Chamber. This is a pyramidal room with a triangular opening nearly 30ft tall. Jess and I sit on a bench at the back and wait for night to fall. Its a cloudless evening, with a sliver of new moon low in the sky. Before long, as promised by Ross, Polaris appears, clear and bright at the apex of the triangle. Polaris, the north star, is around 430 light years from Earth, directly above the north pole.

Its the star that travellers have used to orient themselves for millennia. Because of the alignment of the work, Polaris doesnt move, but the stars below it arc round from one side of the triangle to the other, each taking exactly an hour. On this still night in the desert, thickly speckled with stars thanks to the absence of light pollution, were experiencing the rotation of the Earth as never before. Its a cosmic experience both literally and figuratively.

On the eastern side of the pyramid are two more lines, the higher of which points to the position of the sun at noon on the summer solstice; the lower to the sun on the winter solstice. There are steps to the top of the pyramid, which offers astounding views of the empty plains stretching out for miles around. At the bottom of the pyramid is a ledge. Jess and I peer over it and gasp: using dynamite, Ross has cut a steep-sided basin into the top of the mesa. At its base is the start of a real stairway to heaven: 163 steep steps leading back up to a circle cut into the pyramid and ringed with stainless steel. Through this, at night, you can see the north star.

This staircase, which rises through a tunnel, is the point of Star Axis. Exactly in alignment with the Earths axis, it demonstrates a phenomenon called precession, the slow cycle of change caused by the wobbling of the Earth. Because of this wobble, Polaris wont always be due north: over the course of 26,000 years, the axis will move to point to different stars, each becoming the pole star until returning to Polaris.

Theres danger, but theres also this possibility of enlightenment. The deserts like space Star Axis

The ancient Egyptians knew about precession. Using nothing more sophisticated than a plumb weight and horsehair, they measured the north stars movement so accurately that, thousands of years later, the Naval Observatory told Ross: We can only better their measurements by the thickness of a few horsehairs. And this is one of the most moving things about Star Axis: it demonstrates the connection between the tiniest details and their grand consequences in the universe.

Ross realised that it would be possible to build a tunnel aligned with the Earths axis which, by moving up it, would allow visitors to trace the progression of the north star over this 26,000-year cycle. At first he envisaged a staircase on the front of the mesa, but then started having recurring dreams that said: You have to enter the Earth to reach the stars. Ross says: My attitude to those kinds of messages used to be What the hells that? and just plough ahead. But Ive learned to listen.

Charles Ross at Star Axis he once fell off the work clutching an 80lb bag of cement

Climbing the long, steep and (as yet) bannister-free staircase after dark, looking at the north star through the circle, youre seeing the axial wobble, as Polaris moves further from its central pole. Youre witnessing the star as it appeared at different stages through thousands of years of history and how it will appear in the future.

The first step will be dated 2100, says Ross. Thats the year when Polaris will be closest to its celestial pole. As you go up and put more effort in, youre going further back and further forward. It approximately goes from 11,000 BC, around the recently proposed time for building the Sphinx, to 15,000 AD. This mindbending concept may be hard to grasp, but the genius of Star Axis is that it shows rather than tells.

Though it combines architecture and science, Ross insists Star Axis an artwork first and foremost. Were not making a measuring device, he says. Were making a place for personal experience. It was always my intention that it should be a whole-body experience. That was the epiphany at the beginning like, This is an interesting idea, but I dont just want this in my head, I want to feel it form around me. To me thats art rather than science and all my scientific advisors would agree. He laughs.

Spinning worlds the view from Star Axis at night

Its certainly a profoundly emotional experience, as is sitting in the chamber at the foot of the stairs and watching the stars move from one side of a rectangular opening to the other in a straight line again, thanks to the works alignment. Youre suddenly hyper-aware of the movement of the heavens and the mystery of the universe. Ill put it this way, says Ross, if you spend enough time there, a different part of your awareness wakes up. I think theres a recognition within the body of these alignments that weve had for ever. Its in our genetic code. A place like Star Axis lets that code express itself.

Ross actually thinks of Star Axis as sky art rather than land art. I had never visited any ancient observatories when I started building this. But when I visit them now I realise from my experience of Star Axis exactly why they built them: to get a feeling for the sky. They wanted to touch it, make it personal. They wanted to have a sense that they were reaching out and making physical contact with those alignments. A sensory experience, thats what they were going for, and you get it immediately if you go to Mayan observatories. Youre immediately in mentally, spiritually, physically.

Troublemakers depicts land art as a Promethean struggle between man and nature, but that is only part of Rosss experience. Moving heavy rocks and trying to get gravity to behave is a struggle. But the real point of his creation, he says, is sensing your place in the universe. I never feel small under the stars at Star Axis, Ross says. I feel more like, Wow, all of this has been made for me for all of us.

Troublemakers is in cinemas from 13 May. This article was amended on 11 May to correct the name of its director, James Crump.

Read more: https://www.theguardian.com/artanddesign/2016/may/11/deserts-and-dynamite-my-journey-to-the-cosmic-heart-of-land-art