CAMBRIDGE — In a cavernous space inside a nondescript building off Route 2, a team of Harvard University astrophysicists and engineers is refining the instruments that will power the world’s largest telescope, which they hope in the coming decade will lead to the discovery of life elsewhere in the universe.
For months, the scientists have been testing an array of sensors and optical equipment that will allow the telescope to see farther and more clearly than any before it. They’re also experimenting with various heaters, fibers, and aluminum tubes that will be used to build a spectrograph so powerful and precise it will be able to measure the mass of rocky planets many light-years from Earth and discern the chemical composition of their atmospheres.
“We’re seeking to make the most sensitive instrument in the history of mankind,” said Andrew Szentgyorgyi, associate director of the solar, stellar, and planetary sciences division at the Harvard-Smithsonian Center for Astrophysics. “We’re looking to find Earth 2.0.”
The scientists are working with colleagues around the world on what they’re calling the Giant Magellan Telescope, a $1 billion device that by 2022 will look out from a mountaintop in the desert of northern Chile toward the far reaches of the universe.
The GMT, as it’s known, is among a new class of what are called “extremely large telescopes.” The telescope will employ seven specially built mirrors, each with a diameter of nearly 28 feet, making it 10 times more powerful than the 26-year-old Hubble Space Telescope, which in two years will be joined in orbit by its successor, the James Webb Space Telescope.
The James Webb, which is expected to cost $8 billion, will allow astronomers to observe parts of the spectrum, particularly invisible infrared energy, that they can’t view from ground-based telescopes.
But proponents of the GMT, already under construction in the Atacama Desert in Chile, say its power will dwarf the Webb, and provide four times better resolution.
It will also use the latest technology to eliminate, as much as possible, atmospheric distortion. Unlike space telescopes, the GMT can be regularly updated.
Beyond seeking evidence of life on other planets, the telescope’s unprecedented light-gathering capacity and resolution will help answer some of astronomers’ most fundamental questions: How did the first galaxies form? What is the nature of the dark matter and energy that make up most of space? What will be the fate of the universe?
“We view the GMT as a gateway to decades of scientific discoveries,” said Charles Alcock, director of the Harvard-Smithsonian Center for Astrophysics and professor of astronomy at Harvard. “This is the project that means the most to us.”
Harvard has committed $24 million to the project, which involves hundreds of scientists around the world. Other major backers include the University of Texas, the University of Arizona, the Carnegie Institution for Science, the Korea Astronomy and Space Science Institute, the Australian National University, and the University of Sao Paulo in Brazil.
More than anything, astronomers are hoping the GMT will detect the same kind of oxygen we breathe on Earth — what is known as diatomic oxygen, or two atoms of oxygen bonded together — in the atmospheres of other planets outside the solar system. That is the most reliable sign of life, they say.
David Charbonneau, a Harvard professor of astronomy who specializes in studying planets that orbit other stars, noted that scientists have already identified thousands of so-called exoplanets elsewhere in the universe. They now believe the universe contains more planets than stars.
“It’s really the first time in human history, with the Giant Magellan Telescope, we’ll have the ability to answer the question of whether we’re alone and whether there are other inhabited worlds nearby,” he said.
But it’s also possible that the GMT may be beaten to the big discoveries.
A similar project by a consortium of European nations is working on what it calls the European Extremely Large Telescope, another billion-dollar project slated for Chile, about 500 miles away. That telescope, which is scheduled to begin operations in 2024, will be even larger than the GMT and may be able to view more distant objects at a higher resolution.
The European telescope uses an experimental technology that relies on about 800 relatively small mirrors. If they work as designed, the telescope should be able to observe stars and planets more quickly, and at farther distances, than the GMT.
“It will use a state-of-the-art technology that has more challenges than the GMT, but also more potential,” said Roberto Tamai, program manager for the European project. “There is certainly competition, but it’s a healthy competition.”
Patrick McCarthy, GMT’s project director, acknowledged that the European telescope has its advantages, but he said the GMT will boast a wider field of vision, and as a result, lose less light as it scans the universe.
It also will use the most advanced spectrograph ever built —
“We think we have an edge,” he said. “But this competition is a win-win for astronomy.”
In the large work space off Route 2 in Cambridge, the engineers are building prototypes and running experiments to ensure that the spectrograph will be stable enough to eliminate as much distortion as possible.
They expect to complete the instrument in 2020, so it is ready to be shipped to Chile before the telescope begins its work.
“If we want this project to succeed, everything we’re doing has to be perfect,” Szentgyorgyi said. “This is a game of inches.”