Terrestrial Planet · Updated May 2026
Mars.
Mars is the fourth planet from the Sun, the Red Planet, with a thin CO₂ atmosphere and an iron-oxide-rich surface that gives it its colour. Its diameter of 6,779 km is roughly half Earth's. A Martian day (24h 37m) is almost the same as Earth's, but a year takes 687 Earth days. Mars hosts Olympus Mons, the tallest volcano in the solar system at 22 km, and Valles Marineris, a canyon system 4,000 km long.
Open Mars in the viewer →Key facts
Olympus Mons is roughly two and a half times the height of Mount Everest measured from sea level — but its base is so wide (600 km) that if you stood on it, the slope would feel almost flat. In the viewer the volcano renders to scale on Mars's surface texture.
Atmosphere
95% carbon dioxide, 2.8% nitrogen, 2% argon, with traces of oxygen and water vapour. Surface pressure is just 0.6% of Earth's — too thin for liquid water to be stable except in transient brines. Dust storms can grow to engulf the entire planet for weeks at a time.
Surface
Vast volcanic plains, ancient riverbeds, polar ice caps of frozen water and CO₂, and impact craters. Recurring slope lineae — dark streaks that appear seasonally — were once thought to be flowing water but are now interpreted mostly as dry granular flows.
Interior
A partly molten silicate mantle and a liquid iron-sulfur core ~1,830 km in radius (confirmed by NASA's InSight lander seismic data, 2018–22). Mars lacks a global magnetic field today, though crustal magnetism preserves evidence of an ancient one.
Formation
Formed roughly 4.5 billion years ago from the same protoplanetary disc as Earth. Its smaller size meant faster cooling — Mars lost most of its internal heat and atmospheric retention within its first billion years.
Orbit
Average distance from the Sun: 227.9 million km (1.52 AU). Eccentricity 0.0934 — its distance from the Sun varies considerably across the year. Axial tilt 25.19°, similar to Earth's, so Mars has seasons too.
Major moons
- Phobos — Phobos is the larger of Mars's two moons and is slowly spiraling inward toward Mars.
- Deimos — Deimos is the smaller of Mars's two moons, an irregularly shaped asteroid-like body.
Notable missions
- Mariner 4 (1965 · Past) — First successful Mars flyby; killed off the canals-of-Mars hypothesis with cratered photographs.
- Curiosity (2012– · Active) — Climbing Mount Sharp in Gale crater, sampling sediments laid down when the crater held a lake.
- Perseverance / Ingenuity (2021– · Active) — Caching samples for a future return mission; Ingenuity flew the first powered flight on another planet (now retired Jan 2024).
How to view Mars in 3D
This page is part of an interactive 3D solar system viewer built with Three.js, WebGL 2.0, and custom GLSL shaders. Mars orbits the Sun in real time alongside every other planet, with adjustable time speed, scale sliders, and a fly mode that lets you pilot a spacecraft between bodies under realistic gravity.
Fly to Mars now →Frequently asked questions
How long would it take to get to Mars?
Roughly 6–9 months on a Hohmann transfer; the launch window opens about every 26 months.
Is there water on Mars?
Yes — abundant water ice in the polar caps and subsurface, plus seasonal frost. Liquid water is unstable on the surface today but flowed there billions of years ago.
How many moons does Mars have?
Two: Phobos and Deimos. Both are small, irregularly shaped, and likely captured asteroids.
Sources & methodology
Numbers cross-referenced with the sources below; surface and atmosphere descriptions reflect findings as of May 2026. Renderings in the 3D viewer use textures based on Solar System Scope and NASA imagery.