Great news for astronomy enthusiasts! The world’s highest astronomical observatory, located at 5,640 meters (18,500 feet) above sea level in the Atacama Desert, is now open. Anyone who has camped on a mountainside knows how much clearer the stars appear from such a vantage point.
Now, imagine observing the starry world from the highest point on Earth. The University of Tokyo Atacama Observatory (TAO) has been constructed and is fully operational on the summit of a mountain in the Atacama Desert. It is now the world’s highest site with a ground-based telescope, providing astronomers with an infrared view of the universe. But constructing this observatory at a peak of 5,640 metres was not an easy task, and took 26 years to come out in its present form. The TAO was first conceptualized 26 years ago to study the evolution of galaxies and exoplanets.
TAO is situated on the peak of Atacama’s Cerro Chajnantor mountain, a location with significant meaning
TAO is situated on the peak of Atacama’s Cerro Chajnantor mountain, a location with significant meaning. In the now-extinct Kunza language of the indigenous Likan Antai community, Cerro Chajnantor translates to “place of departure.”
The area’s high altitude, sparse atmosphere, and consistently arid climate are inhospitable to humans but ideal for infrared telescopes like TAO. Infrared telescopes rely heavily on low moisture levels for observational accuracy, as this renders Earth’s atmosphere transparent in infrared wavelengths. Yuzuru Yoshii, a professor at the University of Tokyo in Japan who has led TAO since 1998, described constructing the telescope on the summit of Mt. Chajnantor as “an incredible challenge, not just technically, but politically too.”
He emphasized the need to engage with Indigenous peoples to respect their rights and perspectives, work with the Chilean government to obtain permission, collaborate with local universities for technical support, and coordinate with the Chilean Health Ministry to ensure safe working conditions at such high altitudes.
“Thanks to all involved, the research I’ve only ever dreamed about can soon become a reality, and I couldn’t be happier,” he added. TAO’s telescope is 6.5 meters long and comprises two scientific instruments designed to observe the universe in infrared, which is electromagnetic radiation with a wavelength longer than visible light but shorter than microwaves.
One of these instruments, SWIMS, will image galaxies from the very early universe to better understand how they formed from pristine dust and gas, a process that remains poorly understood despite decades of research.
According to the mission plan, the second instrument, MIMIZUKU, will complement this by studying primordial dust disks in which stars and galaxies are known to form. “The better astronomical observations of the real thing can be, the more accurately we can reproduce what we see with our experiments on Earth,” explained Riko Senoo, a graduate student at the University of Tokyo and a TAO researcher. Discussions about the observatory have been ongoing for the past 26 years, but on-site work commenced only in 2006 with the paving of the first access road to Mt. Chajnantor’s summit and the subsequent installation of a weather monitor.
