[Dates in brackets are last edit.]

    D.01 Do neutrinos have rest mass?  What if they do? [2002-05-04]
    D.02 Have physical constants changed with time? [1997-02-04]
    D.03 What is gravity? [1998-11-04]
    D.04 Does gravity travel at the speed of light? [1998-05-06]
    D.05 What are gravitational waves? [1997-06-10]
    D.06 Can gravitational waves be detected? [2000-08-31]
    D.07 Do gravitational waves travel at the speed of 
         light? [1996-07-03]
    D.08 Why can't light escape from a black hole? [1995-10-05]
    D.09 How can gravity escape from a black hole? [1996-01-24]
    D.10 What are tachyons?  Are they real? [1995-10-02]
    D.11 What are magnetic monopoles?  Are they real? [1996-07-03]
    D.12 What is the temperature in space? [1998-04-14]
    D.13 Saturn's rings, proto-planetary disks, accretion disks---Why
	are disks so common? [1999-07-18]

[Interesting note: The Astrophysical Journal was founded in 1895 by
George Hale and James Keeler.  Professor Edward Wright points out that
these men would not have understood most of these questions---let
alone have known any of the answers.]