Among the ALMA Radio Antennas

Radio telescopes can observe 24/7. They are not looking at the same light as we see with our eyes, they are detecting invisible microwave and radio wave light, at the low end of the electromagnetic spectrum. On Sunday, the ACEAP team got to walk among the Atacama Large Millimeter/sub millimeter Array (ALMA) while the telescope was observing. It was at 16,404 feet elevation - an extreme environment!

A full car on the way up!

It was very interesting to see the scenery change as we went higher and higher up. Eventually there was no vegetation at all. The lower amount of oxygen, cold, and wind make it very difficult for green things to grow.

I had felt fine at high altitudes all week, so I didn't expect the low oxygen to bother me. However, when I got out of the car at the top I immediately felt strange. I moved very slowly and tried to breathe very deeply, but still felt odd. The medics tested all of our blood oxygen level, and I learned I was at about 68. At sea level, you should have a blood oxygen level of 95-100. At the high site, the medics wanted us to have at least 80. They gave me continuous oxygen though a canister. After I had that, I felt fine.

Its amazing what a little oxygen will do for you!

To help us get acclimated, they first gave us a tour of the correlator building. In order for the 66 dishes to work as one large telescope, their signals have to be combined in a super computer. The correlator multiplies the signals from the various antennas and saves the data to files that contain all the information necessary to form a 2D image. 

There are four stacks of computers, all containing solid state drives and with special protections for cosmic rays.

The workers are only allowed to stay at the high site for a maximum of 8 hours. They started in 2 hour shifts and worked up to being able to stay much longer. We were only allowed to stay for 2 hours.

After we saw the super computers, we went outside to see the radio antennas! They followed us with an ambulance so the medics could keep an eye on us. They were a little worried about having so many newbies up there at once.

It was gorgeous, windy, and very cold up there!

They reminded me of Imperial Walkers, but these machines are used only for good.

The triangle in the foreground is a place where an antenna could be moved to. The dishes can be configured to image a large part of the sky, or zoom in on one small part.

The smaller dishes were built by the Japanese. The are usually configured in a compact array, which allows ALMA to study objects with a large angular size.

The dishes were made by three different countries, but really the only way to tell is that the European ones have stairs, and the US ones have ladders on the back.

Watch a short video I took on my iPhone while at the high site. I apologize for the wind. 

The high site was an incredible, harsh environment. ALMA is doing cutting edge science, studying the far away and cold Universe. Because it observes objects in the microwave and radio wavelengths, it can see right through clouds of dust or the bright light at the center of galaxies. Check out this short video to get a overview of one of ALMA's most exciting observations yet. 

I'm back home in Peoria, where it is warm and green - the Chile adventure seems far removed from here, but it is one I'll never forget. I'll write a post about our last day in San Pedro soon. If you have enjoyed following along with my adventure, be looking for information about a lecture at the Peoria Riverfront museum soon!