Giant Magellan Telescope Project
The Giant Magellan Telescope (GMT) will be one member of the next class of giant ground-based telescopes that promises to revolutionize our view and understanding of the universe. It will be constructed in the Las Campanas Observatory in Chile. Commissioning of the telescope is scheduled to begin in 2022.
Australia, through The Australian National University and Australian Astronomy Ltd, is a founding partner in the GMT project, and the Australian Government has invested $88.4 million in the project.
Other members of the international consortium of leading universities and science institutions comprising the GMT project include the Carnegie Institution for Science, Harvard University, the Korea Astronomy and Space Science Institute, The São Paulo Research Foundation – FAPESP, The Smithsonian Institution, Texas A&M University, the University of Arizona, the University of Chicago, and the University of Texas at Austin. More information regarding the GMT project and Las Campanas Observatory can be found at www.gmto.org.
GMT Design & Technology
The GMT has a unique design that offers several advantages. It is a segmented mirror telescope that employs seven of today’s largest stiff monolith mirrors as segments. Six off-axis 8.4 meter or 27-foot segments surround a central on-axis segment, forming a single optical surface 24.5 meters, or 80 feet, in diameter with a total collecting area of 368 square meters.
Light from the edge of the universe will first reflect off of the seven primary mirrors, then reflect again off of the seven smaller secondary mirrors, and finally, down through the center primary mirror to advanced instruments. There, the concentrated light will be measured to determine how far away objects are and their composition.
The GMT primary mirrors are made at the Richard F. Caris Mirror Lab at the University of Arizona in Tucson. They are a marvel of modern engineering and glassmaking; each segment is curved to a very precise shape and polished to within a wavelength of light—approximately one-millionth of an inch. Although the GMT mirrors will represent a much larger array than any telescope, the total weight of the glass is far less than one might expect. This is accomplished by using a honeycomb mold, whereby the finished glass is mostly hollow.
One of the most sophisticated engineering aspects of the telescope is what is known as “adaptive optics.” The telescope’s secondary mirrors are actually flexible. Under each secondary mirror surface, there are hundreds of actuators that will constantly adjust the mirrors to counteract atmospheric turbulence. These actuators, controlled by advanced computers, will transform twinkling stars into clear steady points of light.
The location of the GMT also offers a key advantage in terms of seeing through the atmosphere. Located in one of the highest and driest locations on earth, Chile’s Atacama Desert, the GMT will have spectacular conditions for more than 300 nights a year. Las Campanas Peak (“Cerro Las Campanas”), where the GMT will be located, has an altitude of over 2,550 meters. The site is almost completely barren of vegetation due to lack of rainfall. The combination of clear nights, altitude, weather and vegetation make Las Campanas Peak an ideal location for the GMT.
The time is right to build the next-generation astronomical observatory. We have a clear technical path forward and a burning set of scientific questions that can only be addressed with a giant telescope. These questions are couched in sophisticated scientific language, but can be reduced to questions that we can all identify with: What is the Universe made of? Where did we come from? Are we alone in the Cosmos? Answering these questions involves studying the properties of planets around other stars, the early formation of galaxies, stars, and planetary systems, the nature of dark energy and dark matter, and the evolution of the elements.
Perhaps one of the most exciting questions yet to be answered is: are we alone? The GMT may help us answer that. Finding evidence of life on other planets would be a momentous discovery—certainly one of the greatest in the history of human exploration. But taking pictures of these so called “extrasolar” planets is extraordinarily difficult. In addition to the vast distance, the biggest problem is the glare of the host star which outshines most of the reflected light of a small distant planet. The unprecedented light gathering ability and resolution of the GMT will help with this and many other fascinating questions in 21st century astronomy.
The Australian National University’s Research School of Astronomy and Astrophysics (RSAA) is a world-class astronomy research group and a major center for the development of astronomical instrumentation and technology.
GMT Founder Representative Professor Matthew Colless, Director of the RSAA and National University (ANU), has this to say about GMT: “It’s going to be one of the biggest telescopes in the world; it’s many times larger than the biggest telescopes that currently exist. By combining the large aperture of the telescope and this extra technology, adaptive optics, we can actually see things that are ten times sharper than the images taken with the Hubble Space Telescope.”
Anne-Marie Lansdown, Deputy CEO of Universities Australia, who joined the GMT Board of Directors in October 2015, said, “Australia is a vital contributor to both international radio and optical astronomy infrastructure. Our early involvement in the GMT allowed Australia to have a role in governance decisions that will be critical to its success,” says Lansdown. “I think the experience we bring in collaborative research infrastructure development will also be of great benefit.”