D declination   -    The   angular   measurement   on   the   sky   analogous   to   north-south   latitude   here   on   the   surface   of   the   Earth.      It   is   one   of   two measurements   used   by   astronomers   to   locate   things   on   the   celestial   sphere.      Right   ascension   is   the   other.      declination   is   the   analogue to longitude on the surface of the Earth. differentiation - The process whereby a planet will arrange its interior into layers of different density.  It requires that the interior had been molten at some point in the history of the planet. distance    modulus    -    The   numerical   difference   between   an   objects   apparent   magnitude   (m)   and   its   absolute   magnitude   (M).      This   value is used in the appropriate equation  to determine the distance to that object.
A A A B B B C C C D D E E E F F F G G G H H H I,J I,J I,J K K K L L L M M M N N N O O O P,Q P,Q P,Q R R R S S S T T T U,V U,V U,V W,X,Y,Z W,X,Y,Z W,X,Y,Z Numbers Numbers Numbers
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