What is the relationship between the size and age of the planets in the solar system?

The planets in the solar system come in a wide range of sizes and ages. In general, the size of a planet is related to its age, but this relationship is not always straightforward. Planets can grow in size over time as they accumulate material from their surroundings.

The four innermost planets of the solar system, Mercury, Venus, Earth, and Mars, are known as the terrestrial planets. These planets are relatively small and rocky, with solid surfaces and thin atmospheres. They are also relatively young, with ages ranging from about 4.5 to 3.5 billion years old.

The four outer planets, Jupiter, Saturn, Uranus, and Neptune, are known as the gas giants. These planets are much larger than the terrestrial planets and have thick atmospheres composed mainly of hydrogen and helium. They are also much older, with ages ranging from about 4.6 to 3.8 billion years old.

The relationship between size and age is not always straightforward, however. For example, the largest planet in the solar system, Jupiter, is actually younger than several of the smaller planets, including Earth and Mars. Scientists believe that Jupiter formed relatively quickly, within the first few million years of the solar system's history, while Earth and Mars took much longer to form.