How does other galaxies differ from out own?
shape, size, starcount, location, interaction with other galaxies
How does one telephone differ from another? One car from another? It's the same kind of thing, if I'm not mistaken.
They differ in almost every aspect possible.
Is there a way to measure how big or small a galaxy is compared to ours? What is the smallest galaxy we know of?
With the caveat that there is still a little debate about it, using doppler shift to find distance (there are other ways for closer galaxies) and measuring the angular size will give the actual size.
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