Mercury
4,879 km (3,032 mi)
Equatorial diameter
The smallest planet and the closest to the Sun. Diameter: 4,879 km, narrower than Jupiter's moon Ganymede.
Published
How big is that?
4,879 km is 1.4 times the Moon and 38% of Earth.
Mercury is the 12th largest of the 39 Cosmic Scale objects, and the 12th largest of the 109 objects across all three SizeItUp games.
Size comparison
To scale, smallest to largest: Mercury in orange beside the Cosmic Scale objects nearest in size, in teal.
| Object | Size | vs Mercury |
|---|---|---|
| Valles Marineris (Mars)The great canyon system of Mars, seen from above and measured end to end. | 3,870 km long | 79% of the size |
| Callisto (Moon of Jupiter)Jupiter's battered outer giant moon, covered in craters. | 4,820.6 km across | about the same |
| Mercury | 4,879 km across | – |
| Titan (Moon of Saturn)Saturn's giant moon, wrapped in a thick orange haze. Measured at its solid surface. | 5,150 km across | 1.1× bigger |
| Ganymede (Moon of Jupiter)The largest moon in the Solar System. | 5,262.4 km across | 1.1× bigger |
In other units
| Metres | 4,879,000 |
|---|---|
| Kilometres | 4,879 |
| Feet | 16,010,000 |
| Miles | 3,032 |
How it's measured
Equatorial diameter. NASA Planetary Fact Sheet.
Planets spin, so they bulge at the equator: the equatorial diameter is a little larger than the distance from pole to pole.
Sources
- nssdc.gsfc.nasa.gov: Mercury: 4,879 km.
Checked against the source on .
Could you have guessed it by eye?
Mercury is one of the objects in Cosmic Scale, a daily size comparison game: you stretch a shape to the size you think is right beside one you know.