" I am left wondering if the same is true, say, for the Milky Way with its half a trillion stars." Interstellar space is vastly more empty (it takes >4 years t

" I am left wondering if the same is true, say, for the Milky Way with its half a trillion stars." Interstellar space is vastly more empty (it takes >4 years to cross to the nearest star at light speed vs few hours from Sun to Pluto). Intergalaxy space is unimaginatively huge and empty. Also, don't forget that space is 3d, so traveling in straight line you won't encounter so many objects as 2d map would suggest.