World's biggest telescope gets green light

The Thirty Meter Telescope (TMT) - due to be the world's widest eye on space - has got the go-ahead for construction on the summit of Mauna Kea, Hawaii. TMT will join 13 others on the extinct volcano but will dwarf them all: the biggest now are the twin 10-metre Keck telescopes. The summit is a perfect location as it offers clear skies for 300 days of the year. If all goes well, observations will start in earnest in 2021. TMT may soon have to cede its size record, though: the European Southern Observatory is planning to have the 39-metre European Extremely Large Telescope on the mountain Cerro Armazones in Chile working early next decade. Not everyone in Hawaii is celebrating: the TMT site is being subleased from the University of Hawaii, but some Native Hawaiian groups are opposing the project, as the land is sacred to them.