21 photographs
Mariner 4 (1965)
The first close-up images of another planet, taken from about 9,800 km, and the first time anyone saw a cratered Mars.
Real data · NASA, ESA, CNSA, JPL
Mars by the Numbers
A planet with half the radius of Earth, over half a century of probes and a sky where sunsets are blue. Here it all is in figures: compared, calculated and, when possible, live.
0,38 gof gravity
687days in its year
22 minEarth–Mars light time (max.)
29,4 kmof relief (Earth: 19.8)
Mars, right now
Computed in your browser from the real orbits of Earth and Mars. It updates itself.
Earth–Mars distance—
Light takes—A radio message takes the same: no real-time conversation is possible.
Northern-hemisphere season—
Next opposition—
Next launch window—
How long would it take you to get there?
At today’s distance, non-stop. Choose how you travel:
Earth vs Mars
The longer bar is 100 %. Mars (orange) always first; Earth (blue) below.
Mean radius53 %
Total surface area28 %
Almost the same as all of Earth’s dry land (148.9 M km²).
Mass11 %
10.7 % of Earth’s mass.
Surface gravity38 %
You weigh 38 % of what you weigh on Earth.
Escape velocity45 %
Mean density71 %
Solar day (a “sol”)103 %
24 h 39 min 35.2 s: 39 minutes longer.
Length of the year188 %
668.6 sols.
Mean distance to the Sun152 %
Sunlight received43 %
43 %: the Sun looks a third smaller.
Air pressure (mean)1 %
Under 1 %: like the pressure some 35 km up on Earth.
Surface temperature
Marte−63 °Cmean · from −143 to +35 °C
Earth+15 °Cmean · from −89 to +57 °C
You on Mars
Three calculators to feel the difference in your body.
Your weight
Your jump
Your Martian age
Air and climate
What the air is made of
- CO₂ 95.3 %
- N₂ 2.7 %
- Ar 1.6 %
- O₂ 0.13 %
- CO 0.08 %
It is almost pure carbon dioxide: you cannot breathe it. Earth has 21 % oxygen; Mars, 0.13 %.
610Pa
Pressure at the 0 m datum (≈ 6.1 mbar, 0.6 % of Earth’s). It is the pressure some 35 km up on Earth: at that pressure pure liquid water boils at about 0 °C.
≈ 60times thinner
Surface air weighs about 0.02 kg per cubic metre (on Earth, 1.2). That is why a 100 km/h wind barely pushes.
25 %of the atmosphere freezes each winter
At the poles, CO₂ freezes and sublimates again: global pressure rises and falls by over a quarter every Martian year (measured by Viking).
240m/s
Speed of sound (on Earth, 343 m/s). Perseverance’s microphones measured it in 2022; on Mars high pitches arrive before low ones.
66 %of the Sun’s apparent size
From Mars the Sun spans 21 arcminutes; from Earth, 32. And the dust makes sunsets blue.
A record-breaking relief
Laser altimetry from the Mars Global Surveyor probe (MOLA) and later measurements.
Height of mountains
Olympus Mons is 2.5 times taller than Everest above sea level and about 600 km across at its base, more than the distance from Madrid to Barcelona.
Canyons: Valles Marineris vs the Grand Canyon
Length
Depth
Maximum width
Four thousand kilometres is almost the width of the USA coast to coast.
29,4km
Total relief of Mars: from −8.2 km in Hellas to +21.2 km on Olympus Mons. Earth, from Everest to the Mariana Trench, has 19.8 km.
7,1km
Depth of Hellas Planitia, about 2,300 km across: the largest well-preserved impact basin on Mars.
≈ 5 kmnorth–south difference
The northern plains lie some 5 km lower than the southern highlands: the Martian “dichotomy”, still without a definitive explanation.
Water ice
The polar caps alone would be equivalent to a water layer 5 to 11 m deep over the entire planet. Radars have also found buried ice at mid-latitudes: under Utopia Planitia, a volume comparable to Lake Superior; and in 2021 the TGO probe saw, in the centre of Valles Marineris, an area with so much hydrogen that it could be ice.
Two tiny moons
Phobos
- Size
- 27 × 22 × 18 km
- Orbit
- 6,000 km above the surface
- One lap
- 7 h 39 min
- Gravity
- 0,0057 m/s²
It circles three times per sol and rises in the west. It is approaching Mars at 1.8 cm a year: in 30 to 50 million years it will break up or crash.
Deimos
- Size
- 15 × 12 × 10 km
- Orbit
- 23,500 km from the centre
- One lap
- 30 h 18 min
- Gravity
- 0,003 m/s²
It is so small that from Mars it looks like a bright star. It takes almost three days to cross the sky.
A different day and year
The Martian day: the sol
88.775 seconds
24 h 39 min 35.244 s. A Martian hour lasts 1 h 1 min 39 s Earth time. The year has 668.6 sols.
The seasons (northern hemisphere), in sols
Spring193
Summer179
Autumn143
Winter154
Its orbit is far more eccentric than Earth’s (0.093 versus 0.017): the distance to the Sun varies from 207 to 249 million km and the seasons are very unequal.
25,19°
Axial tilt (Earth, 23.44°): that is why Mars has seasons much like ours, but almost twice as long.
1955Martian year 1
Scientists number Martian years from 11 April 1955, when the first one that could be well observed began.
24,07km/s
Mars’s mean orbital speed (Earth travels at 29.78): that is why Earth “overtakes” Mars every 26 months.
The trip
54,6M km · closest
On 27 August 2003 Mars came within 55.76 million km, the closest in about 60,000 years.
401M km · farthest
When it is on the far side of the Sun (conjunction), communication is cut for about two weeks.
26months between windows
Only every 780 days are Earth and Mars well placed to travel on little fuel.
259days: minimum-energy transfer
The cheapest trip in fuel takes about eight and a half months and needs about 3.6 km/s from low Earth orbit.
Travel days of real missions
Mariner 7 flew faster (and did not brake: it just flew past). Those that stay in orbit or land take six to ten months.
Exploration in figures
2.245 sols
Viking 1 (1976–1982)
It worked on the surface for about six years, a record that stood for almost thirty years, until Opportunity beat it in 2010.
100 metres
Sojourner (1997)
The first Mars rover, the size of a microwave oven, drove a little over a hundred metres around its lander.
5.111 sols
Opportunity (2004–2018)
It was designed for 90 sols: it lasted almost 57 times longer, until the 2018 global dust storm cut its power.
45,16 km
Opportunity’s odometer
It drove farther than a marathon (42.195 km), the longest distance covered by any vehicle on another world at the time.
72 flights
Ingenuity (2021–2024)
The first helicopter on another world was meant to make five test flights; it made 72, about 128 minutes airborne and up to 24 m high.
+1.300 quakes
InSight (2018–2022)
Its seismometer detected over thirteen hundred “marsquakes” and revealed the size of the core and the thickness of the crust.
122 grams
MOXIE (Perseverance)
The first device to make oxygen from the air of another planet: in total about three and a half hours of breathing for one person.
0,3 m per pixel
HiRISE (MRO)
The most powerful camera in Mars orbit tells apart one-metre objects: rocks, dunes and even the rovers themselves from above.
7 minutes
Landing Perseverance
It enters at about 20,000 km/h and must brake to zero in seven minutes, while the signal takes over eleven to reach Earth: by the time you know, it has already happened.
10 landings
Successful landings
Only two countries have operated on the surface of Mars: the USA (9) and China (1). The Soviet Union got there in 1971, but its lander fell silent after 14.5 seconds.
Planned versus achieved
Opportunity× 57
Ingenuity× 14
Spirit× 24
Radiation: the challenge of living there
Mean dose equivalent per day (mSv), measured by Curiosity’s RAD instrument and other detectors. Square-root scale so Earth is visible.
Earth (natural background)
International Space Station
Surface of Mars
Trip to Mars (transit)
≈ 100times more than on Earth
Each day on the surface of Mars you receive about a hundred days’ worth of the natural radiation you get on Earth.
660mSv
Estimated dose of a round trip with 360 days in transit, close to NASA’s career limit (600 mSv).
Severalmetres of regolith, ice or rock
Covering a habitat with several metres of material cuts the dose a lot: that is why in the Atlas the cities are underground, in lava tubes, in canyons or inside the ice.
In our database
The missions in Horizonte Marciano, counted live.
66 missions catalogued
Orbiters
Flybys
Landers
Rovers
Helicopters
Sample return
Missions by launch decade
121960s
151970s
21980s
81990s
92000s
72010s
112020s
Agencies with most missions
- NASA32
- OKB-115
- ESA7
- Roscosmos5
- CNSA4
- JAXA1
Where the data come from
- NASA Mars Fact Sheet (NSSDC / Goddard): radius, mass, gravity, day, year, orbit, atmospheric composition and pressure.
- MOLA, Mars Global Surveyor (Smith et al., 1999): relief, Olympus Mons, Hellas and the dichotomy.
- NASA/JPL · ESA · CNSA: missions, dates, operating sols and distances (Viking, Pathfinder, Spirit, Opportunity, Curiosity, InSight, Perseverance, Ingenuity, Zhurong, Tianwen-1).
- RAD (Curiosity) · Hassler et al., Science 2014; Zeitlin et al., Science 2013: radiation in transit and on the surface.
- SHARAD / MRO · Stuurman et al., 2016: ice under Utopia Planitia. TGO / FREND · Mitrofanov et al., 2022: hydrogen in Valles Marineris.
- Perseverance · Maurice et al., Nature 2022 (sound); Hoffman et al., Science Advances 2022 (MOXIE).
- Orbits of Earth and Mars: Keplerian elements (JPL), computed right here for the “Right now” section.
Rounded figures are rounded on purpose; some (such as the kilometres driven by rovers still active) change over time.