Free Astronomy Magazine November-December 2019

NOVEMBER-DECEMBER 2019 Locations in Spain, Chile, Morocco and Argentina were tested, and fi- nally, in April 2010, Cerro Arma- zones in Chile was selected. It was the ideal site thanks to a mixture of different geographical factors which set it above the rest — such as elevation, climate and the very dark skies of the Atacama Desert. The Chilean desert also has very lit- tle rainfall (100 mm annually on av- erage), a median wind speed of 25 km/h and very little water vapour in the air, making it the perfect loca- tion for successful astronomy. ESO’s Very Large Telescope (VLT) is only 23 km away meaning a lot of the infra- structure needed to build and main- tain the ELT was already in place. There are many questions the Uni- verse has yet to answer and the ELT is well equipped to solve these mys- teries. One of the ELT’s biggest goals is to find and characterise the atmospheres of rocky exoplanets in habitable zones. The ELT will also study star forma- tion, metal enrichment, the physics of high redshift galaxies, cosmology and fundamental physics. A detail of the work in progress on the construction site. [ESO] mosphere, making the images sharper than those taken from space. The enclosure itself will be a classic dome shape and will be the telescope’s first defence against the elements. The dome height comes in at nearly 74 metres from the ground and it will span 86 metres in diameter. Since the ELT is the largest telescope ever built to date — the question of where to put it was a very tricky one to answer. !