The last antenna of the radiotelescope ALMA (Atacama Large Millimeter/submillimeter Array) was delivered earlier this week to the Observatory. It’s a 12-meter-diameter dish produced by the European AEM consortium. Now this astronomical radiointerferometer has all its 66 antennas planned to conduct its scientific research.
The delivery was received with obvious satisfaction by Wolfgang Wild, the ALMA European project manager, who stated that it’s a fundamental step for the Observatory because it allows astronomers to use it in its final form, with all its sensitivity and collecting area.
These words point stress the fact that ALMA was already running but with only part of its 66 antennas it couldn’t operate at its best. Given the complexity and length of the work, its tests started in the summer of 2001, when the number of antennas installed was enough to use it.
ALMA became operational in autumn 2011 but of course every new antenna made it more powerful. Though the array wasn’t yet complete, in March 2013 the official inauguration of ALMA took place with Chile’s President Sebastián Piñera as guest of honor. In fact, it was built in the Atacama desert in Chile, probably the driest place in the world and also at about 5,000 meters (about 16,500 feet) above sea level. These are ideal conditions thanks to stable weather conditions and to the reduction of disturbance caused by the atmosphere.
Those are the conditions that allow observation at millimeter and submillimeter wavelengths. Not many places in the world offer the opportunity to build an array so complex and it still took a long time to build it in difficult conditions like a desert at that altitude. Not accidentally, ALMA is the result of an international collaboration that has taken years of work. This isn’t a single telescope but an array of 66 antennas working together and today it’s impossible to send all those antennas in space, which would be the ideal place.
In the three years of operation, ALMA has already provided excellent scientific results. Now that all the 66 antennas are aimed at deep space, we can expect even better results.