The court said the $1.5 billion project could not go ahead until objections were heard.
Many native Hawaiians have been opposed to construction on what they regard sacred ground at the summit of Mauna Kea, a 4205-metre dormant volcano on the island of Hawaiʻi.
Hawaii’s Board of Land and Natural Resources issued the permit in 2011.
“Quite simply, the Board put the cart before the horse when it issued the permit. Accordingly, the permit cannot stand,” the judgement reads.
TMT’s next move is uncertain.
“We thank the Hawaii Supreme Court for the timely ruling and we respect their decision,” said Henry Yang, Chair TMT International Observatory Board of Directors.
“TMT will follow the process set forth by the state, as we always have. We are assessing our next steps on the way forward. We appreciate and thank the people of Hawaii and our supporters from these last eight-plus years.”
The TMT would be the Northern Hemisphere answer the European Extremely Large Telescope and the Giant Magellan Telescope (GMT), now under construction in Chile.
To mark work beginning on the GMT Cosmos is running a competition in which you could win a Dobsonian six-inch telescope. Click here for details.
Bill Condie is a science journalist based in Adelaide, Australia.