The ALMA Observatory, commissioned March 13, soon will have 66 antennas located more than three miles above sea level. You can take a virtual tour of the extreme environment on the ALMA Explorer website. // ALMA (ESO/NAOJ/NRAO)/C. Padilla
What has 65 siblings, lives 3.1 miles (5 kilometers) above sea level, and sees the invisible?
As far as I know, the only thing that fits that description is an antenna in the Atacama Large Millimeter/submillimeter Array (ALMA), a 66-element telescope in Chile that was just inaugurated March 13. Currently, 55 antennas are operational and on site, but the missing 11 are due to arrive shortly.
The antennas’ combined data give the telescope a resolution of 10 milliarcseconds — 10 times better than Hubble. ALMA could distinguish a single pepperoni on a pizza 325 miles (523km) away.
Well, at least it could if it were sensitive to visible light. Instead of picking up the visible nanometer-wave photons, ALMA picks up micrometer and millimeter waves. Our eyes are not sensitive to those photons, though, which have lower energy than visible photons. From high in the Chilean desert, ALMA and its electronics and correlator — a supercomputer of 134 million processors that, together, do 17 quadrillion calculations every second — thus see the invisible parts of the universe. Then, astronomers use software to turn those invisible light waves into maps that show the shape and intensity of the regions and objects emitting this radiation.
ALMA, an international collaboration between the National Radio Astronomy Observatory, the European Southern Observatory, and the National Astronomical Observatory of Japan, is poised to do awesome science on star and planet formation and teach us much about the complex molecules in space.
To learn more about this new mega-telescope, check out the ALMA Explorer, a map that lets you hop around to different parts of the Atacama Desert. You can take a virtual tour of the telescopes, the wildlife, the nearby town, the control room, and the infrastructure that makes it all work. Videos feature inside looks into places you’d need an oxygen tank to explore, as well as discussions with the facility’s astronomers, engineers, fiber-optic-cable-makers, and more.
Take a deep breath, go to the ALMA “high site,” meet the 55 brothers and sisters, remember all their names and defining characteristics, and ponder the future of big astronomy.