Summary: When you look into the night sky with your eyes, or through a telescope, you're seeing the Universe in the spectrum of visible light. Unfortunately, this is a fraction of the entire electromagnetic spectrum, ranging from radio waves to gamma radiation. And that's too bad because different wavelengths are better than others for revealing the mysteries of space. Technology can let us "see" what our eyes can't, and instruments here on Earth and in space can detect these different kinds of radiation. The submillimeter wavelength is part of the radio spectrum, and gives us a very good view of objects which are very cold - that's most of the Universe. Paul Ho is with the Harvard-Smithsonian Center for Astrophysics, and an astronomer working in world of the submillimeter. He speaks to me from Cambridge, Massachusetts.
