If, all the initial gas was taken up by star formation, then an elliptical is the most likely outcome. Initially, astronomers obtain a spectrum of the galaxy. They identify the spectral lines and measure the red-shift. Using Doppler effect, one can then calculate the recessional velocity. Hubble's law tells us that the recessional velocity is directly proportional to the distance of the galaxy from us.
Voids are empty regions of space, where there is no detectable matter.
A bubble model of the universe pictures matter only on the surfaces of the bubbles, while the interior of the bubble is void. Slices of our universe, that have been plotted so far do give some indications of this model. In a 36 degree slice of the universe, we observe a huge 70Mpc x 200Mpc structure called the Great Wall. Thus, the distribution of matter shows Large Scale Structures, and is not found to be uniform. The energy emission seems to come from a small compact area, also showing jets of emitted matter.