Space time guides
Short, searchable pages for parents, teachers, and curious kids — each links to our calculator and deeper planet or moon articles.
Age calculator
Exact ages on every world + family mission mode
📋Classroom kit
45-minute Mars time lesson plan
📌Shareables
Infographics for Pinterest & social
Popular: Earth age on another planet
9 planets × 26 ages — 234 guides total.
10 on Mars
Classic classroom question
18 on Mars
Graduation on another world
10 on Jupiter
Barely one Jupiter year
8 on Mercury
More than 33 Mercury years
30 on Saturn
Less than one Saturn orbit
65 on Neptune
Retirement age in Neptune years
12 on Venus
Middle school on Venus
21 on Pluto
Coming of age on Pluto
Browse by planet
How long is a day on each moon?
29 moon day-length guides.
Europa
~85h Earth day · Jupiter
Titan
~383h Earth day · Saturn
Io
~42h Earth day · Jupiter
Enceladus
~33h Earth day · Saturn
The Moon
~656h Earth day · Earth
Show all 29 moons
- Day on The Moon
- Day on Phobos
- Day on Deimos
- Day on Io
- Day on Europa
- Day on Ganymede
- Day on Callisto
- Day on Amalthea
- Day on Mimas
- Day on Enceladus
- Day on Titan
- Day on Iapetus
- Day on Rhea
- Day on Dione
- Day on Tethys
- Day on Hyperion
- Day on Miranda
- Day on Titania
- Day on Oberon
- Day on Ariel
- Day on Umbriel
- Day on Triton
- Day on Proteus
- Day on Nereid
- Day on Charon
- Day on Styx
- Day on Nix
- Day on Kerberos
- Day on Hydra