Paper short abstract:

Based on anthropological research with astrobiologists, this paper shows how astronomical conceptions of 'distance' are being redefined and illustrates that the interplanetary medium is losing its privileged status as the boundary of boundaries.

Paper long abstract:

Exoplanets are currently all the rage. Such planets that orbit other stars than the Sun are among the frontiers of cutting-edge astronomy and their discovery in the 1990s is commonly portrayed as one of the great advances of modern science. Yet there is something strange about this setup: exoplanets have no counterpart. They are, by definition, very faraway — lightyears away in fact. Nearby, here down on Earth, there apparently exist no equivalents. In conventional astronomy there is no such thing as an endoplanet. Based on research with astrobiologists, this paper documents the appearance of an alternative wherein the nearby is, astronomically speaking, not less interesting than the extremely distant. What does it mean to be 'faraway' and to be 'close-by' anyway? Nobody envisages dinosaurs as aliens. Even though extinct, they are still our family; we may be distant relatives, but all terrestrial life is ultimately connected. While it may have looked quite differently during the Cretaceous Period, the ancient Earth is never qualified as an alien planet. Martian forms of life, if they are ever found, will be qualified as aliens however. And Mars itself is, by default, an alien planet. So the distance between 'us' and dinosaurs is deemed less than the distance between 'us' and hypothetical Martians living today. The ancient Earth is conceived of as somehow closer to our present Earth than contemporary Mars. Astrobiologists have begun to suspect that this peculiar conception of distance is a rather arbitrary feature of modern metaphysics.