With a day just 37 minutes longer than Earth's and a surface gravity only a third as strong, the dry, red world of Mars is a surprisingly familiar, yet profoundly alien, neighbor sculpted by numbers that tell a story of cold deserts, thin air, and ancient mysteries.
Key Takeaways
- Mars has an equatorial radius of 3,396.2 km and a polar radius of 3,376.2 km, giving it an oblateness of 0.0059
- The mean density of Mars is 3.9335 ± 0.004 g/cm³, which is about 71% that of Earth
- Mars has a surface gravity of 3.72076 m/s², approximately 38% of Earth's gravity
- Mars has a semi-major axis of 1.52366231 AU (227,939,100 km) in its orbit around the Sun
- The orbital eccentricity of Mars is 0.0934, causing significant variation in distance from Sun
- Mars' orbital period (sidereal) is 686.971 days (1.88085 Earth years)
- Mars' atmosphere is 95.32% carbon dioxide by volume
- Atmospheric pressure at Mars' surface averages 6.36 mb (0.63% of Earth's)
- Nitrogen makes up 2.59% of Mars' atmosphere
- Tharsis Montes volcanic region hosts Olympus Mons at 22.5 km height
- Valles Marineris canyon system stretches 4,000 km long, up to 7 km deep
- Hellas Planitia impact basin is 2,300 km wide, 7.1 km deep
- Mariner 4 flyby in 1965 returned 21 images covering 1% of surface
- Viking 1 lander operated 2,245 sols, analyzed 15 soil samples
- Pathfinder Sojourner rover traveled 100 m, lasted 83 sols
Mars is smaller, colder, and less dense than Earth with a thin atmosphere.
Atmosphere and Climate
1Mars' atmosphere is 95.32% carbon dioxide by volume
Verified2Atmospheric pressure at Mars' surface averages 6.36 mb (0.63% of Earth's)
Verified3Nitrogen makes up 2.59% of Mars' atmosphere
Verified4Argon constitutes 1.93% of the atmosphere
Directional5Oxygen is 0.174% by volume in Mars' atmosphere
Single source6Water vapor ranges from 0.03% to 0.03% (variable)
Verified7Carbon monoxide is 0.0747%
Verified8Scale height of Mars' atmosphere is 11.1 km
Verified9Atmospheric temperature at 0 km altitude averages 210 K (-63°C)
Directional10At 100 km, temperature is 148 K
Single source11Blackbody temperature is 209.8 K
Verified12Bond albedo is 0.25
Verified13Atmospheric thermal escape is significant, with Jeans parameter λ = 28 at exobase
Verified14Dust opacity during storms reaches tau=5.0
Directional15Polar CO2 ice cap volume in summer is 1.2 × 10^6 km³
Single source16Residual north polar cap thickness is 1,000 km diameter, 300 m thick
Verified17South polar cap can grow to 3,200 km diameter in winter
Verified18Atmospheric circulation has three cells due to Coriolis effect
Verified19Global dust storms recur every 1.5 to 3 Mars years (2.1-4.2 Earth years)
Directional20Wind speeds on Mars can reach 30 m/s (110 km/h) in dust devils
Single source21Helium abundance is 1.2 ppm
Verified22Krypton is 30 ppb, xenon 4 ppb
Verified23Methane plumes detected up to 0.7% of atmosphere locally
Verified24Ozone column density peaks at 3.8 nm-equivalent
Directional25Water ice clouds form at 40-50 km altitude
Single sourceAtmosphere and Climate Interpretation
Mars has essentially built itself a thin, carbon-dioxide-filled terrarium so leaky and desolate that your average breath would be an act of industrial production, your skin would boil without a pressure suit, and a stiff breeze could summon a planet-wide dust storm that lasts for months.
Geology and Surface Features
1Tharsis Montes volcanic region hosts Olympus Mons at 22.5 km height
Verified2Valles Marineris canyon system stretches 4,000 km long, up to 7 km deep
Verified3Hellas Planitia impact basin is 2,300 km wide, 7.1 km deep
Verified4Northern lowlands cover 40% of surface, average depth 5.5 km below datum
Directional5Southern highlands have crater density >200 craters >16 km diameter per 10^6 km²
Single source6Tharsis bulge spans 5,000 km, elevation up to 10 km
Verified7Over 635,000 impact craters identified >1 km diameter
Verified8Lava flows on Elysium Planitia cover 200,000 km²
Verified9Gale Crater rim height is 4-5 km above floor
Directional10Jezero Crater delta spans 20 km wide
Single source11Recurring slope lineae (RSL) observed on 100+ sites, up to 500 m long
Verified12Hematite spherules ("blueberries") 0.2-0.8 mm diameter in Meridiani Planum
Verified13Clay minerals cover 4.6% of surface, concentrated in Noachian crust
Verified14Phobos Deimos craters: Stickney on Phobos is 9.5 km diameter
Directional15Polar layered deposits thickness up to 3 km in south pole
Single source16Mangala Valles outflow channel 800 km long
Verified17Syrtis Major Planum dark albedo region 1,500 km across
Verified18Arabia Terra plateau has 5 km relief
Verified19Acidalia Planitia smooth plains unit covers 5 million km²
Directional20InSight detected 174 marsquakes, largest magnitude 4.7
Single source21Cerberus Fossae fractures total 1,300 km length
VerifiedGeology and Surface Features Interpretation
Mars is a planet of record-breaking extremes, from the solar system's tallest volcano and grandest canyon to ancient, battered highlands and vast, smooth plains, all whispering a complex geologic history of fire, ice, and relentless cosmic bombardment.
Human Exploration and Missions
1Mariner 4 flyby in 1965 returned 21 images covering 1% of surface
Verified2Viking 1 lander operated 2,245 sols, analyzed 15 soil samples
Verified3Pathfinder Sojourner rover traveled 100 m, lasted 83 sols
Verified4Spirit rover drove 7.73 km over 2,208 sols before 2010 entrapment
Directional5Opportunity rover odometry 45.16 km in 5,352 sols until 2018 dust storm
Single source6Curiosity rover has driven 29 km as of 2023, drilled 39 rock samples
Verified7Perseverance rover collected 24 rock samples by 2023, flew Ingenuity 72 times
Verified8InSight lander measured 1,332 marsquakes over 1,000+ sols until 2022
Verified9Mars Reconnaissance Orbiter imaged 99.9% of surface at 6 m/pixel CTX resolution
Directional10Odyssey orbiter mapped global radiation levels, detected 640,000 craters >1 km
Single source11Mars Express detected subsurface ice radar, mapped aurora
Verified12MAVEN measured atmospheric loss rate of 100 g/s
Verified13Tianwen-1 orbited, landed Zhurong rover 90 m drive in 2021
Verified14Hope orbiter measured 2,500+ clouds in first year
Directional15Mariner 9 mapped 85% of surface at 1 km resolution
Single source16Phoenix lander confirmed water ice at 70 cm depth, operated 147 sols
Verified17MOM (Mangalyaan) orbited 7.5 years, self-located relay failure in 2022
Verified18Insight mole penetrated 2-3 cm into soil after 500+ cycles
Verified19Ingenuity helicopter flew 72 times, total 128 min flight time by 2024
Directional20Global Surveyor altimetry measured 1 m height accuracy over 40 million km²
Single source21MRO HiRISE imaged 45,000+ targets at 25 cm/pixel
VerifiedHuman Exploration and Missions Interpretation
From humble flyby snapshots to sophisticated geological field trips and sky-scraping helicopters, our relentless campaign of robotic emissaries has collectively transformed Mars from a distant, blurry myth into a meticulously measured world of quakes, craters, ice, and ancient secrets waiting in a tube.
Orbital and Rotational Properties
1Mars has a semi-major axis of 1.52366231 AU (227,939,100 km) in its orbit around the Sun
Verified2The orbital eccentricity of Mars is 0.0934, causing significant variation in distance from Sun
Verified3Mars' orbital period (sidereal) is 686.971 days (1.88085 Earth years)
Verified4Perihelion distance for Mars is 206,620,000 km (1.381 AU)
Directional5Aphelion distance is 249,200,000 km (1.666 AU)
Single source6Mars' orbital inclination to the ecliptic is 1.85061 degrees
Verified7The longitude of ascending node for Mars is 49.558 degrees
Verified8Argument of perihelion is 286.502 degrees
Verified9Mean tropical year for Mars is 668.59 sols (686.98 Earth days)
Directional10Mars' rotational velocity at equator is 240.6 m/s
Single source11The solar day (sol) on Mars lasts 24.6597 hours
Verified12Mars' synodic period with Earth is 779.94 Earth days
Verified13Maximum angular size of Mars from Earth is 25.1 arcseconds
Verified14Minimum angular size is 3.5 arcseconds
Directional15Mars' opposition magnitude is -2.91
Single source16Angular velocity in orbit is 0.524 degrees/day
Verified17Mars' Hill sphere radius is 1,077,000 km
Verified18The planet's orbital velocity at mean distance is 24.13 km/s
Verified19Maximum orbital velocity is 26.50 km/s at perihelion
Directional20Minimum orbital velocity is 21.97 km/s at aphelion
Single source21Mars' precession rate of perihelion is 0.558° per Martian century
Verified22The axial precession period for Mars is about 170,000 years
Verified23Mars' mean motion is 0.191 Earth days per degree
Verified24The planet experiences dust storms that can cover the globe every 3 Martian years on average
DirectionalOrbital and Rotational Properties Interpretation
Mars, for all its fiery reputation, is a shockingly indecisive neighbor, taking nearly two of our years to complete its wildly eccentric, lopsided loop around the Sun, which makes its climate just barely hellish one season and then plunge it into a deep freeze the next, all while spinning at a near-identical pace to Earth and occasionally burying itself alive in global dust storms just to keep things interesting.
Physical Characteristics
1Mars has an equatorial radius of 3,396.2 km and a polar radius of 3,376.2 km, giving it an oblateness of 0.0059
Verified2The mean density of Mars is 3.9335 ± 0.004 g/cm³, which is about 71% that of Earth
Verified3Mars has a surface gravity of 3.72076 m/s², approximately 38% of Earth's gravity
Verified4The escape velocity from Mars' surface is 5.03 km/s
Directional5Mars' sidereal rotation period is 24.6229 hours (1.025957 sol)
Single source6Mars completes one rotation on its axis every 24 hours, 37 minutes, and 22 seconds
Verified7The axial tilt of Mars is 25.19 degrees, similar to Earth's 23.44 degrees
Verified8Mars' mass is 6.4171 × 10^23 kg, which is 0.107 Earth masses
Verified9The moment of inertia factor for Mars is 0.366, indicating a less centralized mass distribution than Earth
Directional10Mars' surface area is 144,798,500 km², about 28% of Earth's
Single source11Mars' equatorial surface gravity is 3.71 m/s²
Verified12The planet's oblateness is calculated as (equatorial radius - polar radius)/equatorial radius = 0.0059
Verified13Mars' volume is 1.6318 × 10^11 km³
Verified14The core radius of Mars is estimated at 1,700–1,850 km based on InSight seismic data
Directional15Mars' mantle thickness is approximately 1,500–1,800 km
Single source16The crust thickness on Mars varies from 30–50 km in the southern highlands to about 10 km in the northern lowlands
Verified17Mars' mean surface temperature is -60°C (-80°F)
Verified18Diurnal temperature variation on Mars can reach 100°C due to thin atmosphere
Verified19Mars' albedo is 0.25, reflecting 25% of incoming sunlight
Directional20The planet's bulk density suggests a core composition of iron and sulfur at about 15-20% of total mass
Single source21Mars' polar moment of inertia is 0.364
Verified22The equatorial bulge of Mars is minimal at 20 km
Verified23Mars' GM (standard gravitational parameter) is 4.282837 × 10^13 m³ s⁻²
Verified24The planet's surface regolith density is about 1.5-2.0 g/cm³
Directional25Mars' crustal density averages 2.9 g/cm³
Single source26The internal heat flow on Mars is estimated at 20-22 mW/m²
Verified27Mars' magnetic moment is less than 1.5 × 10^13 A m² today, remnant from ancient dynamo
Verified28The planet's J2 gravitational harmonic is 1965.62 × 10^-6
Verified29Mars C20 is -8.65 × 10^-6, indicating slight pear shape
DirectionalPhysical Characteristics Interpretation
Mars is so modestly squashed, so gently dense, and spins with such polite lethargy that it seems less a failed Earth and more a planet practicing mindful minimalism.
Sources & References
- Reference 1NSSDCnssdc.gsfc.nasa.govVisit source
- Reference 2MARSmars.nasa.govVisit source
- Reference 3ENen.wikipedia.orgVisit source
- Reference 4NATUREnature.comVisit source
- Reference 5AGUPUBSagupubs.onlinelibrary.wiley.comVisit source
- Reference 6SCIENCEscience.orgVisit source
- Reference 7IOPSCIENCEiopscience.iop.orgVisit source
- Reference 8SCIENCEDIRECTsciencedirect.comVisit source
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- Reference 10SCIENCEscience.nasa.govVisit source
- Reference 11ESAesa.intVisit source
- Reference 12LPIlpi.usra.eduVisit source
- Reference 13LASPlasp.colorado.eduVisit source
- Reference 14EMIRATESMARSMISSIONemiratesmarsmission.aeVisit source
- Reference 15ISROisro.gov.inVisit source
- Reference 16MGS-MAGERmgs-mager.gsfc.nasa.govVisit source
- Reference 17HIRISEhirise.lpl.arizona.eduVisit source