The biggest and baddest telescope in the world stands atop a volcanic peak in the Atlantic Ocean off the coast of Africa. The Grand Canary Telescope, with a diameter of 10.4 meters, is the largest single-aperture optical telescope humans have ever built. Nevertheless, it’s not that exceptional—there are a dozen telescopes scattered around the world nearly as large. And much, much bigger telescopes will soon dwarf it.

On Wednesday, construction began on what will probably be the first of a new generation of supermassive optical telescopes. The Giant Magellan Telescope, or GMT, will have seven 8.4-meter mirrors that will combine for a diameter of 25 meters. The telescope will be built on a mountaintop in Chile and could open as early as 2022.

After a groundbreaking ceremony, bulldozers will begin leveling a road to the 2,516-meter summit and preparing to lay a foundation for the 1,100 ton telescope next year. “We’re ready. We’re going to be aggressive on construction,” Patrick McCarthy, interim president of the GMT Organization, told Ars from the site in Chile.

Super telescopes

The GMT partnership of several US universities, as well as institutions in Australia, Korea, and Brazil, is not the only organization trying to build a massive telescope. An international consortium plans to construct the Thirty Meter Telescope in Hawaii, and the European Southern Observatory has begun work on the European Extremely Large Telescope in Chile, planned to measure a staggering 39 meters across.

The new generation of large telescopes will open up broad new vistas for astronomers, allowing them to look deeper into the history of the Universe, when the first stars and galaxies formed. Their new observations may also elucidate the nature of dark matter and dark energy and could potentially sniff out the signatures of life in the atmospheres of exoplanets. As such, there is a tremendous race to reach first light and begin using these large instruments. Nobel Prizes await.

Although it is the smallest of the great new telescopes, the GMT appears to be in the lead. Its backers have raised $500 million of the telescope’s $1.05 billion cost. By breaking ground now, the 200 workers on the mountain can lay the instrument’s foundation and complete the telescope dome by 2020. They can then install the telescope and related optics by 2022.

Giant Magellan Telescope

Ray Bertram, U. of Arizona

Ray Bertram, U. of Arizona

Ray Bertram, U. of Arizona

Ray Bertram, U. of Arizona

Ray Bertram, U. of Arizona

Ray Bertram, U. of Arizona

Ray Bertram, U. of Arizona

Ray Bertram, U. of Arizona

Ray Bertram, U. of Arizona

Yuri Beletsky, Las Campanas Observatory

The GMT organization has already made progress on the most critical aspect of the telescope, its large mirrors. It takes six years from ordering the materials to final polishing to build a single mirror. One has already been finished at the University of Arizona’s Richard F. Caris Mirror Lab, two are in various states of grinding, and the third is very slowly cooling off after an oven melted its glass. Preliminary work has also begun on the fifth mirror.

The directors of the GMT intend to begin operating the telescope with just four mirrors, a configuration that will allow them to take some types of observations with nearly the fidelity of a full instrument. For example, McCarthy said, four mirrors will allow astronomers to look back to the early Universe almost as well as with a seven-mirror telescope.

With this week’s groundbreaking, the 2022 start date anticipated for GMT observations looks a little more realistic. It also stacks up favorably to its competitors.

The competition

The Thirty Meter Telescope, led by California institutions and backed by the Gordon and Betty Moore Foundation, has also indicated that it will begin scientific work with its instrument by 2022. However, when the organization attempted to begin construction atop Mauna Kea on Hawaii’s Big Island this April, demonstrators blocked the vehicles from reaching the summit. Since then, astronomers have been locked in a dispute with indigenous rights protesters. An astronomer familiar with the controversy said the Hawaiian telescope would unlikely be operational before the mid-2020s, if then.

The European telescope consortium, with its even more ambitious 39-meter instrument, has indicated a readiness date of 2024. The telescope has already had a groundbreaking ceremony in Chile, but significant engineering challenges remain before the instrument, weighing nearly 3,000 tons, becomes operational.

Although there is competition between the three projects, overall they bode very well for the astronomy community. Even the smallest instrument, the GMT, will have a resolving power 10 times greater than the Hubble Space Telescope. And with all three instruments online, there will be telescopes in both hemispheres, which is critical to studying the entire Universe.

The GMT got its name from the Magellanic Clouds spied by Ferdinand Magellan as he circumnavigated the globe from 1519 to 1522. These two dwarf galaxies are visible only from the Southern Hemisphere at the edge of the Milky Way Galaxy.

Not that McCarthy wouldn’t be willing to sell you the telescope’s naming rights. Sure, raising the first half of a large telescope’s cost is the hard part, as backers are more apt to join a project once they see it’s really going to happen. But the GMT still needs half a billion dollars. For perhaps half of that, you could name the telescope that's likely to make discoveries as profound as those of the Hubble.

Listing image by Ray Bertram, U. of Arizona