---
name: Astronomy
slug: astronomy
type: discipline
status: running
version: 13800000000.0.1
released: "~13.8 billion BCE"
maintainer: observable universe (delegated to humans, reluctantly)
dependencies:
  - mathematics
  - physics
  - patience
  - darkness
  - clear skies
license: Public Domain (the sky belongs to no one and everyone argues about this)
tags:
  - science
  - cosmos
  - light
  - deep time
  - humility engine
---

Astronomy

What it actually is

The practice of looking at very old light and drawing conclusions about where everything came from, where it is going, and why none of it particularly cares about you.

How it works

Point instrument at sky. Instrument ranges from naked eye to a mirror the size of a parking structure.
Collect light (or radio waves, or gravitational waves, or neutrinos, if you are feeling ambitious).
The light you are receiving is old. Sometimes older than Earth. Accept this.
Convert photons into numbers. Convert numbers into claims about stellar composition, distance, velocity, mass, and fate.
Publish. Wait for the next instrument generation to slightly contradict you.

The core loop has been running for approximately 5,000 years. Most of the UI has changed. The sky has not.

Features

Time travel, read-only. Every observation is a historical document. Looking at the Andromeda galaxy is looking 2.5 million years into the past.
Scale calibration. Reliable cure for anthropocentrism. Side effects include vertigo and a sudden interest in cosmology podcasts.
Civilization infrastructure. Navigation, calendars, agriculture, GPS. Astronomy was load-bearing before anyone called it a discipline.
Gravitational wave detection. Recent addition. Two black holes collided a billion years ago and we heard it. With a ruler.
Exoplanet catalogs. Thousands of worlds confirmed. Most are inhospitable. All are interesting.

Known bugs

Light pollution: urban environments degrade core functionality for most users. The product works best far from its most enthusiastic audience.
Cosmic expansion is accelerating: the observable universe is getting smaller over time. Objects are crossing the event horizon permanently. This is not fixable.
Dark matter: comprises ~27% of universal content. Still no direct detection. Referenced in every cosmology paper. Essentially a TODO comment that has been there for 90 years.
The Fermi Paradox: expected output includes signals from other civilizations. Actual output is silence. Investigation ongoing.

Configuration

observation_mode: visual | radio | infrared | x-ray | gravitational
aperture: 7mm (human eye) to 39m (ELT, forthcoming)
location: preferably high, dry, dark
sky_conditions: seeing < 1 arcsecond preferred
patience_required: true
career_warning: funding is finite, universe is not

Changelog

Version	Notes
~3000 BCE	First stable release. Babylonian calendar integration.
~150 CE	Ptolemaic model ships. Geocentric. Works. Wrong.
1543	Copernican patch. Heliocentric. Better.
1687	Newtonian gravity module merged. Major performance improvement.
1915	General relativity hotfix. Corrects Mercury. Bends light.
1929	Universe found to be expanding. No one asked for this.
1990	Hubble Space Telescope deployed. First images blurry. Corrected.
1998	Expansion accelerating. Dark energy added to dependencies.
2015	Gravitational wave detection. New sense unlocked.

FAQ

Is Pluto a planet? No. This question is deprecated. See taxonomy for why humans struggle to let categories go.

Can I do astronomy without a telescope? Yes. Humans did it for millennia. The moon, the planets, the Milky Way are accessible to anyone in genuine darkness. Genuine darkness is the hard part.

Will the sun destroy the Earth? Yes. Approximately 5 billion years. Plenty of time. Probably.

drafting spec…