1. Rocky Composition: All inner planets are primarily composed of rock and heavy metals. They have solid surfaces and lack the gaseous atmospheres characteristic of the outer planets.
2. Smaller Size and Mass: Compared to the gas giants, the inner planets are significantly smaller in size and mass. This is due to their formation closer to the Sun, where lighter elements were blown away by solar wind.
3. Closer to the Sun: As their name suggests, the inner planets orbit much closer to the Sun than the outer planets. This results in shorter orbital periods and higher surface temperatures.
