1The Voyager probes have entered interstellar space, carrying their golden records beyond the heliopause.
2Is interstellar travel a plausible ambition for humanity this century, or does the energy requirement render it a distant fantasy?
3Astronomers did not detect the interstellar object until it had already passed perihelion and was leaving the solar system.
4Consider the sheer improbability of an interstellar grain of dust surviving its million-year journey only to burn up in our atmosphere.
5There exists, in the interstellar medium, a complex chemistry of organic molecules that may seed the formation of life on nascent planets.