Scientists from the University of California are working with a team of international researchers on one of the most high-profile science projects of this decade: an effort to construct the largest optical telescope on Earth.
The $986 million project is planned for the summit of Mauna Kea, on Hawaii’s Big Island, and will feature a primary mirror 98-feet in diameter.
Scientists working on the project hope to begin construction next year and complete it by 2018 or 2019. They say the facility, dubbed the Thirty Meter Telescope, will allow astronomers to observe with much more clarity some of the earliest stars and galaxies of the universe and investigate what they’re made of.
“We’ll be able to look back at the baby pictures of the universe and trace how it developed,” said Michael Bolte, director of the University of California Observatories and a member of the board of directors for the new telescope.
The telescope won approval last month from the University of Hawaii Board of Regents, which holds the lease to the site.
In addition to exploring the farthest reaches of the universe, the telescope also will be able to routinely and easily produce images of the more than 450 planets that have been discovered orbiting stars outside of our solar system.
Today, the existence of these so-called “exoplanets” can only be inferred by measuring the gravitational tugging forces exerted by the stars they orbit. The telescope also could help determine if some of them have atmospheres similar to Earth’s – the precursor to finding life on another planet.
“It will be one of the most important scientific facilities of the 21st century,” said Bolte, who is also a professor of astronomy at UC-Santa Cruz. “When we look back, it’s going to be the Large Hadron Collider and the Thirty Meter Telescope and I’m not sure what else.”
The project is a joint effort of the University of California, the California Institute of Technology and the Association of Canadian Universities for Research in Astronomy.
A sizable amount of its funding is coming from the Bay Area. The Betty and Gordon Moore Foundation, in Palo Alto, has pledged $200 million toward the telescope’s construction. The University of California and Caltech each plan to raise $50 million. And contributions are expected from the Canadian universities, as well as the governments of China, India and Japan. But 10 to 20 percent of the telescope’s budget still remains to be raised, said Bolte.
The new telescope’s 98-foot (30 meter) mirror would be three times as big as the mirrors on the twin Keck telescopes in Hawaii, currently the biggest in the world, and also owned by the University of California and Caltech. The telescope would produce images three times as sharp as the 33-foot Keck telescopes on Mauna Kea, and would be able to look at objects that are nine times fainter. This would make it possible for scientists to better understand the origins of the universe.
“The universe is 13.7 billion years old and we can see objects that are 13 billion years away, but all we get is fuzzy blobs,” said UC-Santa Cruz astronomer Garth Illingworth, chair of the telescope’s Science Advisory Committee. “We’d like to learn more about these stars and galaxies.”
In January of 2010, Illingworth and his team announced that they had observed the most distant galaxies ever seen. Looking back in time 13 billion years, they found galaxies that were just 600 or 700 million years from the Big Bang. Photographs of these galaxies, which appear as several tiny dots, were made by the Hubble Space Telescope.
Space-based telescopes like Hubble have an advantage over ground telescopes because they don’t have to contend with the blurring caused by the Earth’s atmosphere. But they’re more expensive and therefore, smaller. Hubble’s mirror is less than 8 feet in diameter.
Bigger ground-based telescopes can gather more light than small space-based telescopes. So they make objects that once were faint appear brighter. And the additional light gives researchers information on the chemical composition of objects like stars.
When astronomers understand what a star is made out of, they can better establish its age. And this allows them to plot out the history of the universe more accurately. What’s understood now is that the Big Bang was followed by a period of darkness that astronomers call the Dark Ages. But it’s not clear how long that period lasted.
“There’s controversy about the period before which there were no stars,” said Jerry Nelson, UC-Santa Cruz astronomer and project scientist for the telescope. “The idea is to establish bounds on this. The question is when do you get stars forming that burn holes through this opaque stuff?”
In addition to answering questions about the history of the universe, observers say the telescope could also eventually lead to new energy sources based on the nuclear fusion that fuels stars.
“All those points of light are nuclear furnaces,” said bestselling San Francisco author Timothy Ferris, who wrote “Seeing in the Dark” and other books about astronomy and telescopes. “And they have something to teach us.”
The telescope’s mirror will be made out of 492 closely fit individual hexagonal glass mirrors. The Keck telescopes were the first to use these segmented mirrors to get around the problems created by gigantic individual mirrors. The Keck telescopes were so successful, said Illingworth, that UC and Caltech envisioned the Thirty Meter Telescope as a way to scale-up the Keck model.
But big ground-based telescopes have their limitations. Though they can give astronomers more light to study, they can’t by virtue of their size alone make objects appear sharper. To reduce the blurring caused by the atmosphere, scientists use a series of techniques called adaptive optics.
“Adaptive optics is like putting glasses on a big telescope,” said Nelson. A telescope with adaptive optics not only sees sharper images of stars, it also sees more stars.
An expensive and technically complicated process, adaptive optics was used on telescopes for the first time to correct distortions on the Keck telescopes. The technique takes advantage of a layer of the atmosphere that starts about 50 miles above the Earth. This layer is made up of sodium atoms brought in by small meteorites that vaporize as they enter the atmosphere.
Scientists point an orange laser toward the sodium layer. The laser excites the sodium atoms, which become like artificial stars, radiating light back toward the telescope. The process allows researchers to correct for atmospheric turbulence, which causes phenomena such as the twinkle that we see around stars.
Other telescopes in the range of the Thirty Meter Telescope are in the works. An 80-foot mirror called the Giant Magellan Telescope is being spearheaded by a group that includes the Carnegie Institution for Science in Pasadena, Harvard University, the universities of Texas and Arizona and the government of Korea. That telescope is scheduled to be completed in 2018. And Europe is working on the aptly named Extremely Large Telescope, which would have a 138-foot mirror.
“They’re strongly complimentary,” said Bolte. “The Giant Magellan and the European telescope will be in the southern hemisphere, in Chile. So we’ll have access to the entire sky.” Having several of these instruments, he said, would make valuable telescope time more readily available to astronomers.
The Thirty Meter Telescope, which would be built at an elevation of about 13,000 feet, has not been without controversy. Environmentalists say its construction would harm the wekiu bug, a native species that lives atop high Hawaiian peaks. Some Native Hawaiians have come out in opposition, saying that the summit of Mauna Kea is sacred and should not have any more construction.
Scientists hope that the Thirty Meter Telescope will provide answers for many current astronomy questions: What is the invisible matter that makes up 25 percent of universe? What is the mysterious energy that is making it expand faster and faster? But Bolte suspects that just as telescopes in the past surprised scientists by revealing that the planets orbit the Sun and that the universe is expanding, the new telescope’s contributions are impossible to fully predict.
“Every time you build a new telescope with significant new capabilities, you usually solve the problems of the day and find new things you didn’t even know were there,” Bolte said. “The Thirty Meter Telescope will be a bigger jump than any other jump we’ve had, so the new discoveries will be all the more unexpected.”