Planetary Comparisons

A comparison of planetary data as it is currently accepted:

Mean Distance from Sun

Mars: 206,640,000 km  Earth: 149,600,000 km

Length of sol and day

Mars sol: 24 hrs 39 min  Earth day: 24 hrs

Length of year

Mars: 669.6 Sols  Earth: 365.256 days

Calendar year

Mars: 669.6 Sols  Earth: 12 months

Axial Tilt

Mars: 25.19 degrees  Earth: 23.44 degrees

Orbital Eccentricity

Mars: 9.34%  Earth: 1.67%

Diameter Of planet

Mars: 6792.4 km  Earth: 12,756.3 km

Orbital speed

Mars: 24.13 km/sec  Earth: 29.79 km/sec

Surface gravity

Mars: .38 G  Earth: 1.00 G

Escape velocity

Mars: 5.02 km/sec  Earth: 11.18 km/sec

Average intensity of sunlight

Mars: .43 Earth  Earth: 1.00

Mean surface temperature

Mars: -55 degrees C  Earth 16 degrees C

Air Pressure

Mars: 6-10 kpascals  Earth: 1001.3 kpascals

Air Composition

Mars: 95% CO2, 3% N  Earth: 78% N, 21% O


Mars: 2  Earth: 1

Areological Epochs

Noachian epoch (named after Noachis Terra): Formation of the oldest extant surfaces of Mars, 3.8 billion years ago to 3.5 billion years ago.  Noachian-age surfaces are scarred by many large impact craters.  The Tharsis Bulge volcanic upland is thought to have formed during this period, with extensive flooding by liquid water late in the epoch.  Atmosphere formed and was stripped away, possibly several times.  Major volcanism occurred during this period as well as bombardment by asteroids, meteorites, and comets.

Hesperian epoch (named after Hesperia Planum): 3.5 billion years ago to 1.8 billion years ago.  The Hesperian epoch is marked by the formation of extensive lava plains indicating that volcanism continued during this period.

Amazonian epoch (named after Amazonis Planitia): 1.8 billion years ago to present.  Amazonian regions have few meteorite impact craters but are otherwise quite varied.  Olympus Mons formed during this period, along with lava flows elsewhere on Mars.  Northern Sea is flooded.  Mars colonized by humans.

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