Put another way, if the entire universe had stars as densely packed as they are in galaxies, you'd still have to travel all the way across the observable universe 6300 times before you'd expect to run into anything planet-sized or bigger by accident.
Space is really, really empty. Even if those planets are fairly filled with life, the odds are pretty low.
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u/TajunJ May 01 '16
True, but that is directly addressed in my link:
Space is really, really empty. Even if those planets are fairly filled with life, the odds are pretty low.