text: a golf ball is to planet earth as earth is to ??? relative scale? our galaxy or ??? i don't think that the earth is as small compared to the sun as a golf ball compared to the earth itself.   i would say a red supergiant, one like antares, the alpha star in scorpius, would be much like the earth when the earth is compared to a golf ball.  new!: i just received the information from wikipedia.com and i did some calculations.  the diameter of a golf ball is about 0.00004 km,  the diameter of our earth is about 12756 km, and the diamter of antares is about 924000000 km.   since calculating the volume requires us to cube the radius (let us ignore the pi and 4/3 for simplicity's sake since in ratio, they don't matter). so: the cube of the radius of the golf ball is 8 x 10^(-15) km cubed, the cube of the radius of our earth is 2.6 x 10^(11) km cubed, and the cube of the radius of antares is 9.9 x 10^(25) km cubed.   we can get a brief idea of their sizes by comparing the powers of 10:   golf ball -> earth is 1 -> 100000000000000000000000000 earth -> antares is 1 -> 100000000000000  so earth is far bigger than a golf ball than antares is than earth (at least from my calculations).   now, returning to the questions, i would say something 1000000000000 times the size of antares, probably a nebula.