Mars is no place for the faint-hearted. Arid, rocky, cold and apparently lifeless, the Red Planet offers few hospitalities. Fans of extreme sports can rejoice, however, for the Red Planet will challenge even the hardiest souls among us. Home to the largest volcano in the solar system, the deepest canyon and crazy weather and temperature patterns, Mars looms as the ultimate lonely planet destination.
Distance from the planet's center to its surface, if the planet's volume were contained in a symmetric sphere
Mars:
3,389.5 kilometers
or
2,106.1 miles
Earth:
6,371 kilometers
or
3,958.8 miles
Half the diameter of the planet from pole to pole
Mars:
3,376.2 kilometers
or
2,098 miles
Earth:
6,356.8 kilometers
or
3,950 miles
Half the diameter of the planet at its equator
Mars:
3,396.2 kilometers
or
2,110 miles
Earth:
6,378.1 kilometers
or
3,963 miles
A measurement of the distance around the equator of Mars
Mars:
21,339 kilometers
or
13,259 miles
Earth:
40,075 kilometers
or
24,901 miles
The distance from the planet's center to the outer boundary of the core
Mars:
Total core:
1,700 kilometers
or
1,056 miles
Earth:
Total core:
~3,400 kilometers
or
2,113 miles
"Solid" inner core:
~1,220 kilometers
or
758 miles
Liquid outer core:
~2,266 kilometers
or
1,408 miles
The sum of the areas of all shapes that cover the surface of the planet
Mars:
144,371,391 square kilometers
(1.4437 x 108 km2)
or
55,742,106 square miles
Earth:
510,064,472 square kilometers
(5.1006 x 108 km2)
or
196,936,994 square miles
The quantity of three-dimensional space that a planet contains
Mars:
163,115,609,799
cubic kilometers
(1.63116 x 1011 km3)
Earth:
1,083,206,916,846
cubic kilometers
(1.0832 x 1012 km3)
A measurement of the amount of matter Mars contains
Mars:
641,693,000,000,000,000,000,000 kilograms
(6.4169 x 1023 kg)
Earth:
5,972,190,000,000,000,000,000,000 kilograms
(5.9722 x 1024 kg)
The planet's total mass divided by its total volume, which gives some clues about the planet's makeup (e.g., how much metal it has) and whether it is solid or gaseous
Mars:
3,933 kilogram/meter3
Earth:
5,514 kilogram/meter3
The gravitational acceleration experienced at a planet's surface
Mars:
3.71 meters per second squared
or
12.2 feet per second squared
Earth:
9.80665 meters per second squared
or
32.174 feet per second squared
The speed an object needs to break free from the gravitational attraction of a planet, moon, or other body without further propulsion
Mars:
18,108 kilometers per hour
(5.03 km/second)
or
11,252 miles per hour
Earth:
40,284 kilometers per hour
(11.19 km/second)
or
25,030 miles per hour
How hot or cold the surface varies between day and night and among seasons
Mars:
-190 to 86° Fahrenheit
-120 to 30° Celsius
150 to 303 Kelvin
Earth:
-126 to 136° Fahrenheit
-88 to 58° Celsius
185 to 331 Kelvin
Measurement of how hot or cool the atmosphere is at different altitudes (heights relative to the surface)
Mars:
-81° Fahrenheit
-63° Celsius
210 Kelvin
Earth:
59° Fahrenheit
15° Celsius
288 Kelvin
The chemical materials that make up a planet
Mars:
Crust and Surface
: mostly iron-rich basaltic rock similar to Earth's thin crust
Mantle: Silicate rock
Core: probably an iron, nickel, and sulfur core, but whether it is hot liquid or cooled metal is not known
Earth:
Crust and Surface: iron magnesium silicate igneous rocks, like basalt
Mantle: Silicate rock rich in magnesium and iron
Core: Iron-nickel alloy
The chemical materials that make up the layers of gases surrounding a planet or moon, which are held in place by the object's gravity
Mars:
Main Gases:
96% Carbon Dioxide (CO2)*
1.93% Argon (Ar)**
1.89% Nitrogen (N2)
0.145% Oxygen (O2)
<0.01% Carbon Monoxide (CO)
Earth:
Main Gases:
78.09% Nitrogen (N2)
20.95% Oxygen (O2)
0.93% Argon (Ar)
0.039% Carbon Dioxide (CO2)
*Carbon dioxide is used for carbonation in beverages. Frozen carbon dioxide is "dry ice."
**Argon is used to make blue "neon lights."
The closest distance between the Sun and Mars as the Red Planet travels in its orbit around the Sun
Mars:
206,655,215 kilometers
2.06655 x 108 km
or
128,409,598 miles
or
1.381 AU
Earth:
147,098,291 kilometers
1.47098 x 108 km
or
91,402,640 miles
or
0.9833 AU*
*The reason that the perihelion of Earth is less than 1 AU is that this is a measure of its closest distance from the Sun (its minimum distance). 1 AU is the average between the minimum and maximum distances.
The farthest distance between the Sun and Mars as the Red Planet travels in its orbit around the Sun
Mars:
249,232,432 kilometers
2.49232 x 108 km
or
154,865,853 miles
or
1.666 AU
Earth:
152,098,233 kilometers
1.52098 x 108 km
or
94,509,460 miles
or
1.017 AU
One half of the longest diameter of an orbital ellipse (radius of the orbit at the orbit's two most distant points)
Mars:
227,943,824 kilometers
2.2794382 x 108 km
or
141,637,725 miles
or
1.523662 AU
Earth:
149,598,262 kilometers
1.4959826 x 108 km
or
92,956,050 miles
or
1.000 AU
The distance Mars travels in its orbit around the Sun.
Mars:
1,429,085,052 kilometers
(1.429 x 109) km
or
887,992,283 miles
Earth:
939,887,974 kilometers
(9.399 x 108) km
or
584,019,311 miles
A measurement of how much Mars' orbit around the Sun differs from a perfect circle; 0 = a perfect circle, and values between 0 and 1 represent an elliptical (oval) orbit
Mars:
0.0933941
Earth:
0.01671123
The angle an orbit is "tilted" relative to a reference plane
Mars:
1.85 degrees
Earth:
0.00005 degrees
The rate of change in Mars' position: how fast it is moving in its orbit around the Sun (its speed)
Mars:
86,677 kilometers per hour
(2.4077 x 104 meters per second)
or
53,858 miles per hour
Earth:
107,218 kilometers per hour
(2.9783 x 104 meters per second)
or
66,622 miles per hour
The time it takes for a planet or other body to make a full orbit of the Sun (or outside of our solar system, its primary star)
Mars:
about 687 Earth days
Earth:
365.25 Days
The angle between Mars' orbital plane and its spin axis
Mars:
25.2°
Earth:
23.5°
Variations in the angle of tilt
Unlike Earth, substantial changes in the obliquity (or tilt) of Mars occur on timescales of hundreds of thousands to millions of years and result in long-term climate change
Changes in the amount of sunlight reaching different latitudes due to the varying orientation of the axial tilt as the planet orbits the Sun
4 seasons, roughly twice as long as those on Earth, but with more variation given Mars' eccentric orbit and the fact its orbital speed varies more as result (fastest when at perihelion; slowest at aphelion)
Season (Northern Hemisphere) | Length of Season on Earth | Length of Season on Mars |
Spring | 93 | 194 |
Summer | 93 | 178 |
Autumn | 90 | 142 |
Winter | 89 | 154 |
The time it takes for a planet or other body to make one rotation (one spin on its axis)
Mars:
24 hours, 37 minutes
(24.623 hours)
1.029 Earth days
Earth:
23 hours, 56 minutes
(23.934 hours)
The distance to Mars varies from about 56 million kilometers (about 35 million miles) to 400 million kilometers (about 249 million miles). Why the difference? And why so close now?
When the Sun comes between Earth and Mars, communications with Mars spacecraft diminish drastically. Find out how the mission teams cope!
When Mars is close, it appears to move backwards from night to night! Find out why.
Find out where and when Mars will be in your neighborhood.
Close is a relative term. At its closest, Mars is still tens of millions of miles away from Earth. Still, the decreased distance during "closest approach" allows for fuel-conserving flights to Mars every 26 months and a good view of Mars once or twice every 15 to 17 years for Earth-bound sky watchers.
For help viewing Mars, please contact your local Night Sky Network astronomy club.
Humans from all cultures around the world have been curious about the "Red Planet" Mars since before recorded history.