Telescopes that search the skies for wavelengths that are too delicate to pass through our atmosphere have to be hoisted up into the air with a giant balloon. The telescopes are mainly made out of metal, so to keep one airborne, balloons the size of football stadiums or bigger are needed. You heard that right: not a football field — a football stadium. BLAST is a telescope I worked with today which will use this balloon mechanism when it observes the universe around us. Today I met with two students who are building the telescope, complete with reaction wheels and motors to allow the telescope to turn and state of the art optics mechanisms to filter light. The frame is about the size of a minivan, and is made of white metal pipes which will hold a larger metal frame, a carbon fiber mirror, and a gigantic cryostat filled with liquid helium, cooled down to below its boiling point near absolute zero. Nate, a graduate student, explained the mechanisms to me as I walked around in wonder. The sheer number of things that had to go exactly right for all the data to be collected and all the systems to function properly was mind-boggling. In addition, most of the equipment needed is not built commercially, so the graduate students have to build it all themselves.
Imagine building a machine including liquid helium, pulse pumps, and yards of spiderweb-thin wire to make a machine that cools down an array of specially designed chips to feed out into a complex computer system you have to code yourself. Doesn’t sound so easy! But this is what the students must do. They are motivated by their desire to search the skies, and I can feel it too, even through the frustration Sara and Simon feel as they sift through mountains of data and run endless tests in order to find the problem with their machine.
Since yesterday, the array in the cryostat was running a little colder — a good sign after the 1o0 milliKelvin discrepancy of the day before. However, the gap wasn’t big enough, and the graphs the computer kept outputting from the complicated programming tests Sara was running were not looking like the uniform, smooth curves she was looking for. I cannot begin to understand how they kept themselves so calm, how they worked through the frustration they must have been feeling at the circumstances there had been no way to foresee. I admired their work today greatly — I can only think how discouraged and frustrated I would be in their situation. When Brian, their collaborator on the Green Bank Telescope, arrived they explained the situation to him and he sat down to work. While some tests were running, Sara also explained to me the science and concepts behind their experiment, including how changes in the Cosmic Microwave Background (leftover radiation from the Big Bang) can show us how energetic events are in the universe, and how the inflation period of the Big Bang happened in thousandths of thousandths of seconds to set the stage for cosmological formations.
Here is a picture of the CMB:
It was incredibly interesting and complicated. It is unfathomable and crazy — the way that we can look back in time using light that is only now getting to us from the far reaches of the universe during the early stages of the universe may be the closest we ever get to time travel. But that doesn’t mean we aren’t going to try, and the UPenn lab is the perfect place to begin to unravel the mysteries of the universe.