Source: http://en.wikipedia.org/wiki/Density

Entityρ (kg/m3) 
Interstellar medium 0.0000000000000000001  
The Earth 5.515
The inner core of the Earth 13.000
The core of the Sun 60.000
White dwarf star 21000000000
Atomic nuclei 2300000000000000000000  
Neutron star 1000000000000000000  
Stellar-mass black hole 1000000000000000000