ALMA —- the Atacama Large Millimeter/submillimeter Array —- doesn’t exactly roll off the tongue; rarely grabs headlines; and although a marvel of engineering, is not the sort of astronomical observatory that produces a lot of screensaver-worthy images. But over the last decade, this billion dollar Chile-based array has quietly pushed the limits on both ends of the cosmic spectrum —- from detecting ionized oxygen near the beginning of time to observing ongoing planet formation around nearby sunlike stars.
In the process, it has steered submillimeter and millimeter astronomy —- what was once an observational backwater —- into the top tier of ground-based astronomy.
Although ALMA is temporarily shut down due to the COVID-19 pandemic, it remains the largest and highest such array of its kind ever operated. Its window onto the sky, high above the surrounding Atacama Desert of northern Chile, continues to provide planetary scientists and cosmologists alike with revolutionary data.
ALMA started its scientific operations in September 2011 while still under construction, with less than a quarter of its antennas. An international collaboration, it is funded by the European Southern Observatory, the U.S.’ National Science Foundation, Canada, Japan, South Korea and Taiwan. And as the host country, Chile gets a tenth of the observing-time. Today, it has 66 antennas used in three different array configurations that observe over bandwidths that lie between the radio and the infrared spectrums.