How did the sun's family of planets and minor bodies originate?
For the first time in human history we know of planets around other stars and many of those other planetary systems look quite different from our own. Many have a planet like Jupiter, or even bigger, nearest to the sun. If we are to understand why this is the case, and how likely it is that there are Earth-like planets elsewhere, we need to better understand how planets form.
We might not be here if it were not for our moon, which makes our rotation axis stable. Our planet might not be as wet and rich as it is if it were not for comets and asteroids that leave dust in our neighborhood. Thus, we must understand the moons and other small bodies too, though modest by comparison these objects had a hand in our fate.
Studies of ancient meteorites, cosmic dust, and comets provide clues to the processes operating in the early solar system, and actually allow dating of events over 4.5 billion years ago. Studying these objects, which have changed little since the first few million years of the solar system’s existence, allows us to understand the components that made up the dust and gas cloud from which the solar system formed, and the processes that led to the formation of planets. These analytical studies, in turn, inform theoretical studies of solar system formation.