as big as it really is
(9 orders of magnitude smaller)
 
The Earth:  Diameter = 13000 km = 1.3x107 m
1.3x107x10-9  ~ 10-2 = 1.3 cm  (a marble)
 
The Sun:  Diameter = 1,400,000 km = 1.4x109 m
(about 100 times the Earth’s)
so it must be 1.4 m (about a foot less than my height)
 
Earth-Sun Distance = 1.5x1011 m (1 Astronomical Unit)
1.5x1011x10-9  = 1.5x102 m = 150 m
  or about one-and-a-half football fields