The largest astronomical installation in the world is now operational. ALMA, or the Atacama Large Millimeter Array, is a vast radio telescope made out of 66 12- and 7-meter dish antennae situated 5,000m above sea level, in Chile. Its purpose is to seek out new life and new civilizations and to boldly go where no telescope has gone before. But no, seriously: its job is to peer into the past and investigate ancient stars and nebulae, peer at planets in other solar systems, and hopefully learn more about interstellar creation and destruction.

For now, only 20 antennae are in position, but 46 more will be added over the next year, resulting in something that looks like the image above (which is an artist’s rendering). The project has been steadily plodding along since the telescope’s site — Chajnantor plataeu in the Andes mountains — was surveyed back in 1995, and the total cost will be over $1 billion; the most expensive ground-based telescope currently under construction. The logistics of the construction are a little mind-boggling: first each antenna weighs 115 tonnes, and must be moved from the 2,900m base camp to the main site by custom-built, 130-tonne, German-made heavy haulers.

Next, the sheer size of the ALMA is quite hard to comprehend: these 66 antennae can be placed as close as 150 meters — or as far apart as 10 miles (16km)! If you watch the BBC video, you can see that the site is dotted with concrete base plates; and when the project is complete, these plates will cover a large swath of the telescope’s plateau. Basically, by moving the antennae around, ALMA’s scientists can change the telescope’s coverage: close together, and they act like a wide-angle lens; far apart, they can focus on a single star or galaxy lightyears way.

As for the kind of images that ALMA will produce, fortunately you won’t have to wait: the European Southern Observatory (ALMA’s operator) has been kind enough to furnish us with an image that was taken with just 12 antennae, as a warm-up exercise. The full-color image is a famous photo of the (fittingly-named) Antennae Galaxies taken by Hubble; the red and orange splotches (gas clouds that we haven’t seen before) are from ALMA (more images). With 12 antennae, Hubble has a much greater resolution — but when all 66 dishes are in place, and spread far enough apart, ALMA will blow Hubble away.

What exactly is ALMA looking for, then? Its primary task is searching “our cosmic origins” — stars and gas clouds that might give us some hints about how the early universe was formed. It will mainly do this by seeking out some of the oldest stars and galaxies and by analyzing their radiological signature; the elements they are made of, the gas clouds they are surrounded by, and so on. ALMA will also be capable of imaging “exoplanets” — planets that are beyond the Solar System and that might support alien life, human life, or both.

Read more at ALMA Observatory (including an overly-dramatic video of the construction site) or Wikipedia