Mercury is the closest planet to the sun in our solar system. It is also the smallest planet in the solar system (now that Pluto is no longer considered a planet). It is a rocky planet with a trace atmosphere. Temperatures on the surface of Mercury range from -193o C to 427o C (-315o F to 800o F). Here is some detailed information about Mercury. Go here to learn about the terms used in the tables about the planets.
Orbital Information about Mercury
| Parameter | Actual Measurement | Scaled to our model |
| Aphelion | 43.4 Million Miles | 1.12 miles |
| Perihelion | 28.6 Million Miles | ~ 3/4 mile |
| Eccentricity | 0.205 | |
| Sidereal Orbit Period | ~88 earth days | |
| Synodic Orbit Period | ~116 earth days | |
| Ave. Orbital Velocity | 105,929 MPH | 14.5 ft/hr |
| Number of Moons | 0 |
Physical Characteristics of Mercury
| Characteristic | Actual Measurement | Scaled to our model |
| Ave. Diameter | 3032 miles (38.3% of Earth) | 4.96 inches |
| Mass | 3.3 x 1023 kg (5.5% of Earth) | |
| Surface Gravity | 3.7 m/s2 (38% of Earth’s) | |
| Sidereal Day | 58.6 Earth days | |
| Synodic Day | 176 Earth Days |
Visualizing Mercury in our scale model of the solar system
A Grapefruit
In this model of the solar system, Mercury would be about 5″ in diameter, roughly the size of a grapefruit.
Here is what the orbital path of Mercury would look like overlaid north of Dallas. Visit our orbits page to see this on an interactive map.
Size comparisons of the inner planets (and Ceres)
