Interferometer, Polarizing, Michelson, Balloon Borne Far-Infrared Spectrometer

Display Status:

This object is on display in the Explore the Universe exhibition at the National Air and Space Museum in Washington, DC.

Collection Item Summary:

This interferometer was part of a ballooon borne infrared spectrometer. That instrument, also known as the Woody Richards experiment, was one of the first designed to test the theory of the Big Bang by analyzing its remnant radiation. The Fourier transform far infrared spectrometer worked on the principle of an interferometer. To achieve maximum sensitivity the assembly was immersed in a cryostat cooled with superfluid helium. Helium 3, which was used in the last flight, cooled the bolometer to below one degree above absolute zero, the first time such a low temperature had been used for astronomical observations. The whole package was borne to high altitudes far above most of the earth's atmosphere by a large helium filled balloon. The spectrometer was used for three flights in the mid-1970s.

The results from these experiments, announced in 1979, provided the most widely accepted support for the Big Bang theory until the announcement of data from Far Infrared Absolute Spectrometer (FIRAS) flown on the Cosmic Background Explorer (COBE) satellite.

This experiment combined novel technologies that were later used on FIRAS/COBE. It was donated to NASM in 1997 by Professor Paul Richards of the Department of Physics at the University of California, Berkley.