Re: Ch. 4: Between the Galaxies
"The universe is not only queerer than we imagine, but queerer than we can imagine." J. B. S. Haldane, Possible Worlds and Other Papers
Dwarf galaxies, runaway stars, gas clouds, dark matter, etc. etc. ad infinitum.
And here I thought inter-galactic space was empty.
Of course, as Tyson reminds us, such ignorance is honest; without the aid of powerful telescopes and other modern detecting devices, we had no way of knowing what was out there. (A side note; 'ignorance,' traced to its roots, simply means 'without knowledge.' There is nothing wrong with ignorance; it is simple recognition that you do not know something. This is not to be confused with 'stupidity' which implies not only a lack of knowledge, but a lack of desire for knowledge.)
It is also interesting to note the (honest) misnaming of many celestial objects; the "Milky Way" (actually the dense center of our own galaxy), the Great Nebula in Andromeda (now the Andromeda Galaxy), the Greater and Lesser Magellanic Clouds (dwarf galaxies). Not bad for naked eye astronomy.
Obviously, the universe is a very crowded place.