ALMA: Extreme, Precision Astronomy in the Desert

The Atacama Large Millimeter/Submillimeter Array, or ALMA, is already producing amazing science results. To see the telescope up close at an altitude of 16,500 feet (5,000 meters) is even more incredible. This high-precision instrument on top of the world is truly one of the most impressive sights that I have ever seen.

So whats the big deal with a millimeter and submillimeter telescope anyway?

PHOTOS: ALMA: New Jewel of the Atacama Desert

ALMA is the most sensitive instrument (by far) to probe this region of the electromagnetic spectrum just a bit longer in wavelength than infrared, yet still quite high energy for most radio astronomers.

It has a special power to see an unbiased sample of the universe. That is, by a combination of an increase of star formation (and thus infrared emission) in the galaxies in the early universe and the way that light is redshifted by the expansion of the universe, you can see a whole swath of the history of galaxies in this band. However, it has traditionally been a difficult place to work since the water molecules in our atmosphere absorb and scatter much of the submillimeter light coming from space.

So, to some of the highest, driest mountain peaks we go.

I came to the Atacama Desert as a guest of the National Radio Astronomy Observatory along with several other science writers from around the United States. At the Operations Support Facility, located at an altitude of 9,500 feet (2,900 meters), we joined an even larger host of journalists from around the world to get a special tour of this remote facility.

The altitude was already wearing on a few of us that are used to sea level, especially when lugging around laptops and camera bags. We had a safety briefing before our trip to the high site where we were instructed on the use of our oxygen bottles and informed that a team of paramedics would be traveling with us to the high site, or Array Operations Site. This was about to get real.

ANALYSIS: ALMA Inauguration: Journey to the Atacama

Despite the occasional dizziness and mild headache once we reached the array, I actually jumped up and down and squealed with excitement upon seeing it in person. There were 54 dishes on site from North America, Europe, and East Asia, all built to the same precise performance specifications but each looking a little bit different. The surface accuracy of the gleaming 12-meter wide dishes is the width of a human hair, and the drives and motors that move them must point to an object with 0.6 arcseconds of accuracy. (Thats like pointing accurately at a single person in Charlottesville, Virginia, from St. Louis. Trust me, thats a LONG drive.) Seeing the arrays in person was beautiful.

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ALMA: Extreme, Precision Astronomy in the Desert

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