When the average person thinks about high-tech telescopes, they usually conjure images of the space age Hubble Space Telescope. Those old enough to remember the launch of that piece of astronomical equipment will also likely recall years of malfunctioning lenses and equally astronomical repair bills, associated with shuttling astronauts into space for maintenance. But a colossal new telescope in Hawaii seeks to end all that, showing that the future of star-gazing could actually be right here, on Earth.
The Thirty Meter Telescope (TMT), which recently broke ground atop Mauna Kea, a volcano on Hawaii’s Big Island, is already being hailed as a game changer by some astronomers. The name refers to the diameter of the telescope’s 30 meter (98 feet) wide segmented mirrors, a system used in most modern observatories to reflect light and create clearer images of distant objects in space. But the TMT would operate on an unprecedented scale.
“It’s really a quantum leap forward compared to other telescopes,” said Derrick H. Pitts, Chief Astronomer for Franklin Institute and an advisor on the TMT project, who noted that the largest terrestrial telescopes at present, at the Keck Observatory, feature mirrors just 10 meters in diameter.
“This telescope will be three times that size. So it will be able to see objects nine times fainter than the Keck telescopes and far, far better than Hubble Space Telescope.” Pitts said previous methods of mirror construction had hit a wall in terms of how large, single pieces of glass could be cast before reaching a physical breaking point. But the new method of mirror construction being employed at the TMT will use many smaller mirror segments to form a massive “primary light-gathering unit.”
TMT will employ 492 hexagonal segments, each a little over a meter in size, to form its 30-meter mirror. Hubble, for comparison, features a mirror that is just 2.3 meters in diameter. But the relatively small size of the HST and the great expense incurred in maintenance was supposed to be made up for by the fact that the space-borne telescope was free from the temperature changes and atmospheric interference that normally plague earth-based observatories.
Pitts said a new “adaptive optic system” would eliminate atmospheric “fog” at the TMT, while its terrestrial location will make maintenance and upgrades much easier and more cost effective — along with other benefits. “The location is ideal for astronomical work, first the summit is at 14,000 feet altitude, above a lot of weather on the planet, and that’s a good thing,” he said. “The skies are very dark there, it’s very cold at that altitude. And there’s a wonderful laminar air flow that comes across the pacific ocean that can be employed to help keep the telescope components at a constant low temp so there isn’t much change in size in any of the instrumentation.”
But at the same time, that prime location has been a source of great controversy. “The mountain itself, Mauna Kea, is a volcano. It’s the largest volcano on the island. But Mauna Kea is also a sacred site to native Hawaiians,” said Pitts. “There’s quite a bit of sensitivity. In fact, there’s some people who really don’t want the astronomers to be there with the instruments.” Mauna Kea is already home to numerous, smaller telescopes that were contentiously built on the sacred mountaintop, now managed by the University of Hawaii. The scope and subsequent international attention on the TMT have inflamed old tensions.
While the university and some local residents support the high-skilled jobs and commerce brought by the existence of world famous piece of astronomical equipment on the island, the site has attracted peaceful protests. One video depicts a protestor in traditional religious garb interrupting the official groundbreaking ceremony, angrily referring to stunned attendees as “snakes” and accusing officials of deceiving locals. The man says the University of Hawaii has done a bad job of respecting sacred burial sites in its operation of previously constructed astronomical equipment.
Pitts says a better dialogue needs to be established to communicate the interests of both astronomers and native Hawaiians. Others say there can be no middle ground.
“If you look back at the history of how the native hawaiians have revered this location, you’ll find that, in fact, they actually restricted their own access to the mountaintop, let alone allowing astronomical observers with large instrumentation to reconfigure the mountaintop as has been done,” said Pitts.