On. Oct. 5, 1962, the European Southern Observatory was born!
The European Southern Observatory (ESO) is an intergovernmental research organization made up of 16 nations that work together to study the southern sky. Before ESO, all the major ground-based telescopes in the world were in the Northern Hemisphere. So ESO built some really big and really awesome telescopes in Chile.
With these telescopes, scientists have discovered exoplanets like Proxima b, they've found the oldest star in the Milky Way, and they've shown that the universe is expanding at an accelerating rate.
Why it mattered
The European Southern Observatory is an oasis of astronomy in the high Atacama desert of Chile, allowing pristine views of the night sky from altitudes that range from 7.900 feet to 16,700 feet (2,400 to 5,100 meters) above sea level.
ESO, as it's known today (it was formerly called the European Organisation for Astronomical Research in the Southern Hemisphere), is actually a group of large observatories - each including multiple telescopes - that are supported by more than a dozen countries for astronomical research. ESO has pioneered the use of adaptive optics, deformable mirrors that change shape to account for atmospheric interference, as laser guide-stars for telescope observations.
ESO's observatories include the Paranal Observatory - which contains the Very Large Telescope and the VISTA telescope for visible and infrared astronomy. Other ESO sites include the La Silla Observatory (which has two ESO telescopes and hosts others from member states), and the Chajnantor plateau, which is home to the giant Atacama Large Millimeter/submillimeter Array (ALMA) radio telescope. The first ESO telescope opened at the La Silla site in 1966, and today the group averages about 1,800 proposals for telescope time each year.
When complete, the Extremely Large Telescope at Cerro Armazones will be the largest visible and infrared light ground telescope on Earth. It will have a 128-foot (39-meter) main mirror to study exoplanets and search for potentially habitable worlds. "It will also probe the furthest reaches of the cosmos, revealing the properties of the very earliest galaxies and the nature of the dark Universe," ESO officials have said.
Want more space history? Check out our full On This Day In Space Story archive and watch our On This Day In Space videos on YouTube.
