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Hubble replacement could solve many of the universe’s strangest mysteries

The Giant Magellan Telescope (GMT) is making news after the third of seven primary mirrors was cast at the University of Arizona’s Steward Observatory Mirror Lab this past Saturday, August 24.

Those working with the massive telescope issued a press release detailing the specifics of both the GMT and Saturday’s event. Members of the press and media were invited to observe the forging of borosilicate glasses into the mirror as it spun in a furnace reaching a temperature of 1,170 degrees Celsius (2,140 Fahrenheit). The final product will weigh a whopping 20 tons.

Each individual mirror is to be 8.4 meters—or 27 feet—in diameter, with the entire series of mirrors reaching a collective diameter of 24.5 meters (80 feet). Arizona’s Steward Observatory lab is the only lab currently capable of developing mirrors of such magnitude.

According to, the first of the seven mirrors has been cast and polished to a surface accuracy within 25 nanometers. The second mirror has also been cast but is still under construction towards completion. Work on the GMT’s facility at the Las Campanas Observatory in Chile is slated to begin next year, with the entire project ready for observations by 2020.

“Astronomical discovery has always been paced by the power of available telescopes and imaging technology. The GMT allows another major step forward in both sensitivity and image sharpness,” said Steward Observatory’s Peter Strittmatter, per GMT’s statement.

“In fact the GMT will be able to acquire images 10 times sharper than the Hubble Space Telescope and will provide a powerful complement not only to NASA’s 6.5-meter James Webb Space Telescope (JWST) but also to the Atacama Large Millimeter Array (ALMA) and the Large Synoptic Survey Telescope (LSST), both located in the southern hemisphere,” he continued.

The sensitivity mentioned by Strittmatter will be achieved through a collection of seven ancillary mirrors that will work to negate the blurriness caused by Earth’s atmosphere. The GMT will use its state of the art functionality to locate and characterize exoplanets and aid in the continuing examination of black hole physics, assisting other studies as needed.

The $700 million project is one of a number of large Earth-based astronomical research endeavors currently in development. Also on the horizon is the Thirty Meter Telescope planned for construction on top of Hawaii’s Mauna Kea, to begin operations by 2025. The GMT will share its future home in Chile with the European Southern Observatory’s Extremely Large Telescope, the biggest of the upcoming Earth-based telescopes at 42 meters in diameter.