Moon
What is Moon?
Moons· Diameter 3,475 km. Earth's only moon and the only other world humans have walked on. Tidally locked, it always shows the same face, and drives eclipses and the monthly phases.
📍 Visible from where you are right now — computed in your browser
bearing · altitude · rise time · best time tonight
Where Moon is in your sky right now: https://nowsky.org/solar/sky?sel=moon — location and time set automatically, no login.
Orbit and size
| Diameter | 3,475 km |
|---|---|
| Distance | 384,400 km |
| Orbit | 27.3 d |
| Note | receding 3.8 cm/yr |
Figures are representative approximations. Source: compiled from NASA and IAU public data.
Parent planet and sibling moons
Related events
- Apollo 11 — first footsteps on the Moon
- Danuri — Korea's first lunar orbiter
- Artemis II launch — crewed lunar flyby
- MMX launch — Martian moon sample return(planned)
- Artemis III — boots on the Moon again(planned)
- Total lunar eclipse — New Year blood moon(planned)
Frequently asked
- How big is Moon?
- 3,475 km.
- How far is Moon from Earth?
- 384,400 km.
- What is notable about Moon?
- receding 3.8 cm/yr.
- Which planet does Moon orbit?
- Earth.
- Where is Moon in the sky right now?
- Open the sky view for your location and time and it shows the position in the sky right now.
The Moon illusion — why the rising Moon looks huge
The Moon on the horizon looks far larger than the Moon overhead, yet measured in a photograph the two are the same size — if anything the horizon Moon is 0.5 percent smaller, being one Earth radius farther away. The illusion has been debated for over two thousand years; the leading account is that the brain judges objects near the horizon to be distant and so interprets an image of the same size as larger. Hold out your arm: the Moon hides behind a fingernail at any height.
A "supermoon" is not an illusion but a real difference. Because the lunar orbit is eccentric, a full Moon at perigee (about 360,000 km) is 14 percent wider and 30 percent brighter than one at apogee (about 400,000 km) — though without the two side by side the eye struggles to tell. Select the Moon in the sky view for today's distance and apparent size, and move the time a few months to watch the disk change.
The moon in depth
Relative to its planet, the Moon is the solar system's largest satellite — over a quarter of Earth's diameter. Its favored origin story is a giant impact 4.5 billion years ago: a Mars-sized body, Theia, struck the young Earth, and the debris coalesced into the Moon. Apollo's rock samples, isotopically near-identical to Earth, are the key evidence.
Tidally locked, the Moon always shows us one face. The nearside is spread with dark maria — ancient lava plains — while the farside is nearly maria-free cratered highlands; until Luna 3's photos in 1959, humanity had never seen that half. Its south carries the South Pole–Aitken basin, a 2,500-km impact scar among the solar system's largest.
Track the Moon in the orbit view and rotate the camera to see the farside yourself; the Sky view gives tonight's phase and rise/set times.
The Moon's standard origin story is a giant impact: a Mars-sized protoplanet, Theia, sideswiped the young Earth, and the splashed debris coalesced into the Moon — Apollo's rock samples, isotopically identical to Earth, are the key evidence. It still recedes 3.8 cm a year, so in a few hundred million years total solar eclipses will retire, leaving only annular rings.
Related
Figures are representative approximations. Simulated positions use J2000 mean elements.