Astronomy facts
One short astronomy fact per day, each with a figure and a source. Pick a topic or scroll back through the days.
October 2026
- Oct 29 AstronautsJohn Glenn Flew in Space at Age 77
- Oct 28 GalaxiesAndromeda Is the Farthest Object Most People See
- Oct 27 Dwarf Planets & Small BodiesCeres Is 25% of the Asteroid Belt
- Oct 26 PlanetsA Day on Jupiter Lasts Under 10 Hours
- Oct 25 MoonThe Hunter’s Moon Turns Full Tonight
- Oct 24 Space HistoryThe First Photos From Space Date to 1946
- Oct 23 Missions & SpacecraftWebb Orbits 1.5 Million Kilometers From Earth
- Oct 22 Space HistoryVenera 9 Took the First Venus Surface Photo
- Oct 21 Night SkyTonight’s Orionid Meteors Are Halley’s Comet Dust
- Oct 20 The UniverseObservable Universe Spans 92 Billion Light-Years
- Oct 19 PlanetsEarth Is the Solar System’s Densest Planet
- Oct 18 Missions & SpacecraftGalileo Launched Toward Jupiter in 1989
- Oct 17 AstronautsISS Astronauts See 16 Sunrises Every Day
- Oct 16 GalaxiesOne Galactic Year Lasts About 230 Million Years
- Oct 15 Missions & SpacecraftCassini Launched to Saturn in 1997
- Oct 14 Dwarf Planets & Small BodiesArrokoth Is a Snowman Made by Gentle Collision
- Oct 13 Black HolesThe First Black Hole Image Spanned Earth
- Oct 12 StarsRed Dwarfs Can Shine for Trillions of Years
- Oct 11 AstronautsApollo 7 Broadcast Live TV From Orbit
- Oct 10 Space HistoryThe Outer Space Treaty Took Effect in 1967
- Oct 9 Night SkyDraconid Meteors Peak as the Moon Nears New
- Oct 8 PlanetsSaturn Is Less Dense Than Water
- Oct 7 SunThe Sun Holds 99.8% of Solar System Mass
- Oct 6 PlanetsFirst Exoplanet Around a Sun-Like Star Found
- Oct 5 MoonThe Moon Has Shrunk About 50 Meters
May 2025
- May 17 PlanetsEarth and Venus Are Closer Than Any Other Planets
- May 16 PlanetsNeptune Is So Far That Sunlight Takes Over 4 Hours to Reach It
- May 15 SunThe Sun Could Fit Over a Million Earths Inside It
- May 14 PlanetsEarth Would Fit Inside Jupiter’s Great Red Spot
- May 13 Space HistoryThe Moon Has Artificial Satellites Orbitting it
- May 12 Space HistoryThe Oldest Satellite Still in Orbit Launched in 1958