Latin America hosts one of the most powerful supercomputers in the world

That's right, a supercomputer as powerful as the top 2 machine on the most recent Top500 list has its home in the Atacama desert in Chile. Although it may not run the traditional HPC software, it certainly enables cutting-edge scientific exploration.

The Atacama Large Millimeter/submillimeter Array (ALMA) is a collection of high-precision antennas that work together as a giant telescope. Using high resolution and sensitivity, ALMA provides a window to understand the origin of the universe.  The antennas are installed in the dry Atacama desert at more than 5,000 meters above sea level. Those conditions are ideal for the type of instrument ALMA embodies.

The general idea of the array of antennas is to capture a signal from the sky by two or more antennas and combine them to analyze the signal and get more information about its source. Images result from combining radio waves collected by different antennas. Therefore, ALMA has the ability to photograph the sky and provide valuable information on the life of galaxies. The proper orientation of the antenna collection is of such precision that it is necessary to run heavy computations. Such information makes it possible to have the antennas precisely pointing at the same region of the sky and have coherent signals that will later be combined into a single image. The computation is carried out by a supercomputer, called the ALMA Correlator.

The correlator can be thought as ALMA's brain; without it, the antenna collection wouldn't work properly. The correlator takes signals from the antennas as input, and produces astronomic data for further analysis. The goal of this process is to multiply the signals from the antennas. The result is saved into files called visibilities, which will later be used to make the images. The correlator contains 134 million processors capable of performing 17 quadrillion operations. It requires 140 kilowatts to cool down the processors. In part, such power consumption is due to the thin air of the Atacama desert. High altitude also precludes the use of hard disks, hence the correlator is diskless.

The correlator was built and installed by the National Radio Astronomy Observatory (NRAO) and funded by the US National Science Fundation (NSF). It is a fundamental part of the ALMA's puzzle and it is already providing the information necessary to understand how planets, galaxies, and stars form.

For more information about the project, please visit http://www.almaobservatory.org.