Protesters demonstrate on a road that leads to Mauna Kea in Hawaii. Credit: Lanakila Mangauil

Trucks carrying construction materials for the $1.4 billion Thirty Meter Telescope (TMT) rolled toward the summit of Mauna Kea on 17 July. But they stopped about 15–20 kilometers short of the turnoff that leads up the mountain; several hundred Native Hawaiians and other opponents of the project blocked the junction.

After years of protests, negotiations, and legal battles, the TMT has the necessary permits to go forward on Mauna Kea. Still, no one was surprised by the protesters, who oppose further building on a mountain that they consider sacred for its ties to their creation traditions and to water deities. The planned site of the TMT would decimate the “ring of shrines,” where Native Hawaiians practice equinox and solstice rituals, says Kealoha Pisciotta, who for many years worked as a technician on Mauna Kea telescopes and now is a cultural practitioner. She says she was dismayed in late July when the TMT board turned down an invitation to meet with her and other leaders of the movement to protect the mountain.

The standoff continues. “At some level, it’s a test of wills,” says Doug Simons, director of the Canada-France-Hawaii Telescope and a member of the Mauna Kea management board. Astronomers in Hawaii say that the TMT has become a symbol of broader issues of concern to the local indigenous community; some also note that there are Native Hawaiians who support the TMT. (See Physics Today, July 2016, page 31.)

In the days that followed, the quiet blockade continued. The governor of Hawaii declared a state of emergency, opening the door to police and military involvement, and 38 Hawaiian elders were arrested. Astronomy graduate students circulated a letter questioning “the methods by which we are getting the telescope on the mountain” and calling on the astronomy community “to recognize the broader historical context of this conflict, and to denounce the criminalization of the protectors on Maunakea.” Quoting Chanda Prescod-Weinstein, an assistant professor of physics at the University of New Hampshire, the letter asks astronomers to “think of the lasting consequences for us of being a community that partners with the military and the police on indigenous land and then publicly brands itself as being about wonder and the majestic.” As of this writing, 947 people, mostly young astronomers from across the US, have signed the letter.

“It’s not culture against astronomy,” says Lanakila Mangauil, who grew up on the slopes of Mauna Kea and is another leader of the diffuse opposition movement. “What we oppose is the massive earth-moving that the TMT requires,” he says. “It would be by far the largest building on the island, and it would disrupt a unique ecosystem that lives in the pahoehoe lava flow.”

The peaceful protesters—or protectors of the mountain—are holding strong. Their numbers haven’t dipped below 1000, Mangauil says, and sometimes grow to 4000 or so. A history of mountain mismanagement and broken promises has led to a feeling of “enough is enough,” he says. “We will keep protesting until the TMT moves.”

Citing concern for the safety of observatory staff, the directors of the 10 operating telescopes on Mauna Kea have closed their facilities. “It’s the functional equivalent of a long cloudy period,” says Simons.

Simons and the other directors also wrote an open letter urging “appreciation of the nuances and complexity of the issues we now face.” They stated, “Conflict about the Thirty Meter Telescope does not change the long-standing support our Observatories have earned, but it will undoubtedly influence its future.”

The primary mirror of the Thirty Meter Telescope, illustrated here, comprises 492 hexagonal segments. Credit: TMT International Observatory

Despite the prolonged conflict and lack of a clear way forward, the TMT team still hopes to build the telescope on Mauna Kea. A backup site on La Palma, one of Spain’s Canary Islands, was selected in 2016. But Mauna Kea is higher and drier; it is the best site in the Northern Hemisphere. Most of the planned science could still be done from La Palma, but because of the thicker atmosphere and higher humidity, observations would take longer, says Christophe Dumas, TMT observatory scientist and head of operations. And the fraction of time that is compatible with observing in the mid-IR is more than 50% on Mauna Kea and only about 20% on La Palma. “We would have to monitor the atmospheric quality and implement adaptive scheduling,” he says. Some science would not be possible from La Palma, Dumas adds, because of greater broadening of spectral lines by the thicker atmosphere.

If the TMT is not built on Mauna Kea, the implications for astronomy in Hawaii could be far-reaching. Federal money for new instruments and upgrades to the existing telescopes on the mountain could dry up, says Simons. Funding is driven by the confidence the agencies have in the future of astronomy on Mauna Kea, he explains, and the “agencies will ask whether it’s reasonable to make major investments here.” Another concern is whether the lease by the state to the University of Hawaii to continue using the mountain for astronomy will be renewed in 2033.

The TMT is already behind schedule by several years; construction is expected to take roughly 10 years once it begins. Two other telescopes in the same size class—the 25-meter US-led Giant Magellan Telescope and the 39-meter European Extremely Large Telescope—are under construction in Chile and on course to see first light around 2025. The US astronomy community has just begun a new decadal survey, in which priorities are set, and astronomers have submitted many white papers highlighting the science that can be done with the extremely large telescopes, says Dumas. Strong praise in the decadal survey will help the TMT project become a reality, he says. The TMT partners are Caltech and the University of California in the US, and Canada, China, India, and Japan.

In the wider astronomy community, many hope that the TMT goes ahead on Mauna Kea. Patrick Osmer, a retired astronomer at the Ohio State University who is not involved in the project, says he hopes that a solution is found, given the quality of the Mauna Kea site. But as the protests continue and gain widening attention, some astronomers and universities are getting cold feet. The University of British Columbia, for example, which participates in the TMT through Canada’s membership, on 26 July called for a 60-day moratorium on the project “to allow for the fulsome consideration of other potential sites for TMT.”

Dumas admits that because the TMT can’t be smaller, “we don’t have much to negotiate.” But, he says, “we believe the telescope will be for the benefit of mankind, and we hope we can find a peaceful solution for everyone.” No firm deadline has been set, but to work with the decadal survey and avoid further cost hikes, a decision about whether to build the TMT on Mauna Kea or switch to the alternate site on La Palma will have to be made in the coming months, he says.