The Universe exploded into being 14 billion years ago and remnant light from this explosion is still visible today. Our group measures this light at a site 17,000 feet high in the Atacama Desert in Chile. We use special "detectors" developed in a collaboration between Princeton and other institutions. These detectors use antennas to capture the non-visible wavelengths of light focused by our 6 meter telescope.

This photograph looks down into feedhorns, small corrugated structures that allow particles of light to funnel toward the antennas. The antennas are tiny dark triangles suspended upon a thin membrane on a silicon detector wafer that attaches to the base of each feedhorn. The membrane is thin enough that you can see the gold-plated reflective wafer behind the antennas. Light from the camera is reflecting off the gold-plated wafer, casting a golden gleam.