Planet · Terrestrial planet

Mars

Type: Terrestrial planet
Diameter: 6,792 km
Distance from Sun: 227.9 M km
Surface gravity: 3.7 m/s²
Mean temp.: -65 °C
Moons: 2

NASA/JPL-Caltech/Cornell Univ./Arizona State Univ. · NASA media (public domain)

Overview

Scientific overview

Mars is a terrestrial planet in orbit around The Sun, at a mean distance of 227.9 million km from the Sun.

Physical characteristics

Mass: 0.642 ×10²⁴ kg
Diameter: 6,792 km
Radius: 3,396 km
Density: 3.933 g/cm³
Surface gravity: 3.7 m/s²
Escape velocity: 5 km/s
Rotation period: 24.6 h
Mean temperature: -65 °C

Scale

Compared to Earth

Earth

Mars

Mars is 1.9× smaller than Earth

6,792 km across · Earth is 12,742 km

Orbit

Distance from Sun: 227.9 million km (1.523 AU)
Orbital period: 1.88 years
Perihelion: 206.6 million km
Aphelion: 249.2 million km
Eccentricity: 0.094
Orbital inclination: 1.9°
Axial tilt: 25.2°
Orbital velocity: 24.1 km/s

Gallery

Mars Celebration
The Mars celebration Saturday, June 1, 2019, in Mars, Pennsylvania.
2019
NASA · NASA media (public domain)
Source archive ↗

Observation

How this was captured

Observatory / instrument: Pancam
Mission: Mars Exploration Rover Opportunity
Source: NASA
Observation date: 2015-09-25

Moons (2)

Notable surface features

Exploration

Sources

The primary and reference sources this topic draws on.

NASANational Aeronautics and Space Administration
Mission data, planetary science, space telescopes, and public-domain imagery.
Most NASA-produced imagery is in the public domain; individual items are checked for usage terms before publication.
NASA JPLJet Propulsion Laboratory / Solar System Dynamics
Orbital data, ephemerides, and small-body parameters for planets, asteroids, and comets.

Quick facts

Type: Terrestrial planet
System: The Sun
Moons: 2

Provenance & sources

review 2026.1

Asteria Scientific Review Process · verification: sourced · accurate

High evidenceconfirmed
Mars is the fourth planet from the Sun, a cold desert world about half Earth's radius, with seasonal polar ice caps and Olympus Mons, the tallest volcano in the Solar System.
Source: NASA (NSSDCA) — NASA Planetary Fact Sheet · Public domain (US Government work)
- NASA Planetary Fact Sheet, Planetary Fact Sheet

Reviewed by the internal Asteria Scientific Review Process — not an external institutional review. See the evidence framework and authority dashboard.

Scientific citations

Real, source-backed references — primary papers first, then datasets and institutional sources. Formatted through the citation engine; nothing is fabricated.

DatasetApproximate Positions of the Planets

NASA Jet Propulsion Laboratory (Caltech)

Cite (APA / BibTeX)

NASA Jet Propulsion Laboratory (Caltech) (n.d.). Approximate Positions of the Planets. NASA Jet Propulsion Laboratory (Caltech). https://ssd.jpl.nasa.gov/planets/approx_pos.html

@misc{cite:jpl-approx-positions,
  title        = {Approximate Positions of the Planets},
  organization = {NASA Jet Propulsion Laboratory (Caltech)},
  year         = {n.d.},
  url          = {https://ssd.jpl.nasa.gov/planets/approx_pos.html},
  note         = {Public-domain Keplerian orbital elements and rates (Standish) — the method behind the computed planet positions, rise/set, and visibility.}
}

DatasetMars Fact Sheet

NASA Goddard — NSSDCA

Cite (APA / BibTeX)

NASA Goddard — NSSDCA (n.d.). Mars Fact Sheet. NASA Goddard — NSSDCA. https://nssdc.gsfc.nasa.gov/planetary/factsheet/marsfact.html

@misc{cite:factsheet-planet-mars,
  title        = {Mars Fact Sheet},
  organization = {NASA Goddard — NSSDCA},
  year         = {n.d.},
  url          = {https://nssdc.gsfc.nasa.gov/planetary/factsheet/marsfact.html},
  note         = {Physical and orbital parameters for Mars.}
}

Institutional pageMars — NASA Solar System Exploration

NASA

Cite (APA / BibTeX)

NASA (n.d.). Mars — NASA Solar System Exploration. NASA. https://science.nasa.gov/

@misc{cite:nasa-planet-mars,
  title        = {Mars — NASA Solar System Exploration},
  organization = {NASA},
  year         = {n.d.},
  url          = {https://science.nasa.gov/},
  note         = {NASA overview of Mars.}
}

Institutional pagePlanets — NASA Science

NASA

Cite (APA / BibTeX)

NASA (n.d.). Planets — NASA Science. NASA. https://science.nasa.gov/planets/

@misc{cite:nasa-planets,
  title        = {Planets — NASA Science},
  organization = {NASA},
  year         = {n.d.},
  url          = {https://science.nasa.gov/planets/},
  note         = {NASA overview of the planets: how the naked-eye planets appear and move through the sky.}
}

Quality & authority

Substantial

Reviewed

Description: None
Source coverage: Complete
Relationship coverage: Complete
Review coverage: Complete
Citation coverage: Complete
Image coverage: Complete

Data from the NASA Planetary Fact Sheet & JPL (public domain). See source quality.

Mars

Scientific overview

Physical characteristics

Compared to Earth

Orbit

Gallery

How this was captured

Moons (2)

Phobos

Deimos

Notable surface features

Exploration

Mars Science Laboratory

Viking 1

Mars Express

Mars 2020

Curiosity

Perseverance

Ingenuity

Opportunity

Spirit

Sources