WILLIAM NORDBERG MEMORIAL LECTURE
 
 

ERIC G. ADELBERGER                UNIVERSITY OF WASHINGTON

 
"Using Laser-ranging to the Moon to Test Fundamental Questions about Gravity"

   The Earth-Moon-Sun system is a marvelously sensitive system for addressing
   several key questions about gravity including

   a) what is the weight of gravity itself?

   b) is Newton's constant G changing as the Universe evolves?

   c) are there new long-range fields associated with galactic dark matter?

   d) how well does the inverse-square law work?

   In addition it is teaching us about the geophysics of the Moon and Earth.

   This technique, which relies on retro-reflectors placed on the Moon by NASA
   over a quarter century ago, is continually becoming more precise--we
   now know that certain distortions of the Moon's orbit characteristic of
   new physics have amplitudes less than 4 mm! I will discuss how new
   technology will allow this precision to improve still further. Farther into
   the future, one could make even better measurements by placing an active
   laser transponder on Mars.
 
 

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