---
title: "Planet-Sized Instrument"
description: "Peter Galison's name, in Planetary Vision, for the Event Horizon Telescope: a virtual telescope with an Earth-wide aperture, assembled by correlating radio dishes on several continents and multiplied by the planet's rotation, which swings each pair into new geometries against the black hole."
type: "glossary-term"
canonical_url: "https://antikythera.wiki/terms/planet-sized-instrument"
md_url: "https://antikythera.wiki/md/terms/planet-sized-instrument"
last_updated: "2026-09-06"
site: "Antikythera Wiki"
---

# Planet-Sized Instrument

> A working definition written for this wiki from the reading notes; not Antikythera's own wording. From Antikythera Wiki (https://antikythera.wiki/terms/planet-sized-instrument), an independent guide to Antikythera's published work.

[Peter Galison](https://antikythera.wiki/people/peter-galison)'s name, in Planetary Vision, for the Event Horizon Telescope: a virtual telescope with an Earth-wide aperture, assembled by correlating radio dishes on several continents and multiplied by the planet's rotation, which swings each pair into new geometries against the black hole. Galison contrasts it with earlier planet-spanning science (geodesy, magnetic surveys, cosmic rays), which measured Earth; here Earth is used, a component of the apparatus rather than its object. The construction is integrative: the working unit is the baseline between two telescopes, and no dish means anything alone. Bratton takes the EHT as the demonstration of what Planetary Computation is for, a planet opening an eye onto its surroundings (Allocentrism), and in the SPOC lectures folds it into Model Epistemology, the image having been simulated before it was seen, an emphasis Planetary Vision lacks. Galison already looks past the planet: the orbiting Black Hole Explorer would outgrow Earth.

## Appears in

- [Planetary Sapience Symposium](https://antikythera.wiki/work/journal/planetarysapience) (2025-11-21)
- [Planetary Vision](https://antikythera.wiki/work/journal/planetaryvision) (2025-11-21)
- [For a General Theory of Simulations](https://antikythera.wiki/work/journal/theoryofsim) (2025-05-10)
- [Speculative Philosophy of Planetary Computation](https://antikythera.wiki/work/journal/spoc) (2025-05-10)
- [Antikythera](https://antikythera.wiki/work/journal/research) (2025-05-10)
- [A New Philosophy Of Planetary Computation](https://antikythera.wiki/work/media/noema-a-new-philosophy-of-planetary-computation) (2022-10-05)

_Glossary generated 2026-09-06._