* Mercury: Mercury has a very thin, almost negligible atmosphere, called an exosphere. It's composed primarily of sodium, potassium, hydrogen, helium, and oxygen.
* Venus: While Venus has a very dense atmosphere, it's primarily made of carbon dioxide, making it incredibly hot and inhospitable.
* Mars: Mars has a thin atmosphere, primarily composed of carbon dioxide. It's about 100 times thinner than Earth's.
* Outer Solar System: The gas giants (Jupiter, Saturn, Uranus, Neptune) all have thick atmospheres. However, their moons, with the exception of Titan (Saturn's moon), have very thin atmospheres or none at all.
Let me know if you'd like more details about any of these planets or their atmospheres!
