TMT International Observatory

Controversial Hawaiian observatory project gets go-ahead despite local protests

Image credit: Artist's impression of Thirty Metre Telescope

An extremely large telescope (ELT) has gained approval for construction after years of discussion and controversy. Placed at the peak of the tallest volcano in Hawaii, Mauna Kea, it is due to become the highest-altitude ELT in the world.

Hawaiian officials gave their approval this week for the $1.4 billion (£1.05 billion) project, voting 5-2 for the construction by the Hawaii Board of Land and Natural Resources.

Officials first granted permission to build the Thirty Metre Telescope (TMT) at Mauna Kea in 2011, although construction was halted in October 2014, following protests by locals. Further protests blocked each attempt to resume construction and in December 2015 the State Supreme Court invalidated the building permits, postponing construction indefinitely.

Many indigenous people have spoken out against the construction, considering Mauna Kea a holy site: a “region of the gods”. They argue that the building of an observatory would affect their spiritual connection to their ancestors and the heavens. The alpine summit of the volcano was forbidden to all but the ali’i, hereditary nobles who took on leadership roles in society.

It would appear that both gods and astronomers favour the mountain, however, given that ground-based telescopes at high altitude are above a significant fraction of the atmosphere, allowing for far less “noisy” observations. The peak of the Mauna Kea, 3.06km above sea level, is an exceptional spot for building an astronomical telescope, with most cloud cover falling below the summit. Due to its favourable conditions, the volcano is already home to 13 much smaller observatories.

The TMT website states that the telescope could allow for discoveries in almost every field of astronomy and astrophysics, including exploration of the early “dark ages” of the universe, exoplanets and black holes through the history of the universe.

The Board of Land and Natural Resources, in its nearly 350-page decision paper, conceded that: “Mauna Kea is the best place on earth to study the heavens.”

In order to placate protestors, the international consortium organising the construction of the telescope will be required to provide $1 million (£750,000) annually for educational programmes, including university scholarships for indigenous people.

In a statement, Professor Henry Yang, chairman of the TMT International Observatory Board said: “In moving forward, we will listen respectfully to the community in order to realise the shared vision of Mauna Kea as a world centre for Hawaiian culture, education and science.”

Locals are due to stage further protests at the site, following this decision, and another legal challenge is expected to appear in Hawaii’s Supreme Court

An ELT is a telescope with an aperture of at least 20m. These huge sizes are achieved using segmented mirrors placed together to create one large mirror, as the technology does not exist to produce such a large single mirror. The TMT will be made from 492 small hexagonal mirrors and will be the second largest in the world, bested only by the planned ELT in Chile (which will have an aperture of 39.3m).

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