The first mirror for the Giant Magellan Telescope (GMT) is now completed. This first 8.4-meter (27.5-foot) GMT mirror is the most challenging large astronomical mirror ever made.
Becoming operational in the next decade under dark southern-hemisphere skies, GMT will lead a new generation of giant telescopes that will explore planets around other stars and the formation of stars, galaxies, and black holes in the early universe.
"Our partnership in the GMT will help the University of Texas retain its status as one of the top astronomy programs in the United States," said McDonald Observatory director David L. Lambert. "It will give our faculty, researchers, and students access to the world's largest telescope and technology well into the future."
The telescope's seven mirrors are being built by optical scientists and engineers at the University of Arizona's Steward Observatory Mirror Laboratory.
"There's only one place in the world that can make these mirrors, and that's the University of Arizona Mirror Lab," says Edward Kolb of the University of Chicago.
This first GMT mirror is the most challenging large astronomical mirror ever made. By the standards used by optical scientists, its "degree of difficulty" is 10 times that of any previous large telescope mirror.
Engineers have polished the mirror into an unusual, highly asymmetric shape that ultimately will fit into a single 25-meter (82-foot) optical surface composed of seven circular segments. Altogether, the seven mirrors working together will provide more than 380 square meters, or 4,000 square feet, of light-collecting area for the telescope.
The Giant Magellan Telescope will peer more deeply into the universe's hidden history than humans have ever attempted. Scientists say the instrument's combined mirrors will be sensitive enough to detect a candle on the moon, or to see the face on a dime 200 miles away.
"When we study the evolution of the universe we can use telescopes as time machines," says Edward Kolb. "Larger telescopes allow us to look farther out in space and further back in time to probe the very earliest history of the universe."
"The Magellan Telescopes will be our tool in optical astronomy for the next 10 years. Beyond that is the Giant Magellan Telescope," says Kolb.
The GMT will combine seven 8.4-meter primary mirror segments operating together as if they were part of a single, 24.5-meter telescope. Its capabilities will exceed those of even the Hubble Space Telescope.
The GMT will address some of the biggest questions in astronomy, including how dark matter affects the movements of galaxies and galaxy clusters, and the role that dark energy has played in the evolution of the universe.
"We know that the universe is made of 74 percent dark energy, 22 percent dark matter, and 4 percent ordinary matter," says Hsiao-Wen Chen, Assistant Professor in Astronomy and Astrophysics at the University of Chicago. Chen is especially interested in the search for "dark" ordinary matter. This is the stuff of stars, planets, and people, yet two-thirds of this dark matter remains missing.
"The missing matter underscores a serious shortfall in our knowledge of the growth of the visible universe," says Chen, who has made many trips to Las Campanas to use the twin 6.5-meter Magellan Telescopes for her research.
The GMT is part of a long-term ambition to understand the nature of dark matter and dark energy, and to glimpse the formation and evolution of extrasolar planets, stars, galaxies, and black holes.
Partners in the GMT organization include the University of Texas at Austin, Texas A&M University, the Carnegie Institution for Science, the Smithsonian Institution, Harvard University, the University of Arizona, the University of Chicago, Astronomy Australia Ltd., the Australian National University, and the Korea Astronomy and Space Science Institute.