The sizes of astronomical objects are so large and the distances are so great that they quickly exceed human comprehension. Each picture below shows increasingly larger objects as one move further from the earth.
Inner planets of the solar system. These planets are the most dense in the solar system and, with the exception of Pluto, closest to the sun.
I am having difficulty in posting images so please kindly go to the link and have yourself amazed....

http://www.quantrek.org/size_comparison/size_comparison.htm