The planets in our Solar System known to have sand dunes are **Earth, Venus, and Mars**. As of now, the only two Solar System planets, besides Earth, with named dune fields are Venus and Mars. While Earth boasts vast sandy deserts and coastal dune systems, evidence from space missions has confirmed the presence of extensive dune fields on these two neighboring planets as well, indicating that the geological processes that form dunes are active on multiple planetary bodies.
## Dune-Bearing Planets in Our Solar System
Sand dunes are landforms created by the wind (or other fluid flows, like liquids) that deposit and shape granular material. The presence of dunes on a planet indicates specific conditions are met: a source of granular material, an atmosphere or fluid capable of moving that material, and an environment where the material can accumulate.
* **Earth:** Our home planet is famous for its diverse dune environments, from vast sandy deserts like the Sahara and the Arabian Desert to coastal areas and even underwater. Earth's substantial atmosphere and varied geology provide ideal conditions for dune formation.
* **Mars:** The Red Planet is covered in stunning dune fields composed mainly of basaltic sand derived from volcanic activity. Despite its much thinner atmosphere compared to Earth, Martian winds are still strong enough to move sand grains, particularly because the lower gravity allows grains to be lifted more easily. Martian dunes range in size and shape, including large fields within craters and near the polar ice caps.
* **Venus:** Surprisingly, Venus, with its extremely hot and dense atmosphere, also hosts sand dunes. These dunes are thought to be composed of different materials than Earth or Mars, possibly including rocky fragments, volcanic ash, or even particles formed chemically in the atmosphere. The planet's thick atmosphere creates very different wind patterns and surface interactions compared to Mars or Earth.
## Other Celestial Bodies with Dunes
It's important to note that while the question specifically asks about planets, sand dunes or similar aeolian features driven by winds or other mechanisms have been found on non-planetary bodies in the Solar System as well. These include:
* **Titan:** Saturn's largest moon, [Titan](https://en.wikipedia.org/wiki/Titan_(moon)), possesses vast dune fields composed of hydrocarbon sands, formed by winds blowing through its nitrogen atmosphere.
* **Pluto:** The dwarf planet [Pluto](https://en.wikipedia.org/wiki/Pluto) shows evidence of dunes, likely formed by methane ice grains moved by faint atmospheric winds.
* **Comet 67P/Churyumov–Gerasimenko:** Even this comet has shown hints of aeolian features, suggesting that granular material can be moved and accumulated in surprisingly low-gravity environments with outgassing activity.
## Summary of Dune Locations
Here is a table summarizing the Solar System bodies where sand dunes or similar features have been identified:
| Body | Type | Presence of Dunes | Notes |
| :----------------------------- | :------------ | :---------------- | :------------------------------------------------ |
| **Earth** | Planet | Yes | Abundant, diverse dune types, atmospheric winds. |
| **Venus** | Planet | Yes | High temperature, dense atmosphere, unique composition. |
| **Mars** | Planet | Yes | Basaltic sand, thinner atmosphere, lower gravity. |
| **Titan** | Moon | Yes | Hydrocarbon sand, nitrogen atmosphere. |
| **Pluto** | Dwarf Planet | Yes | Methane ice grains, faint atmosphere. |
| **67P/Churyumov–Gerasimenko** | Comet | Evidence Found | Likely related to outgassing. |
Thus, focusing strictly on planets within our Solar System, Earth, Venus, and Mars are currently confirmed to have sand dunes.
