1.The solar system consists of the Sun, planets, dwarf planets, moons, comets, asteroids, meteoroids, dust, atomic particles, electromagnetic radiation, and magnetic fields. Each component of the solar system has its own specificproperties.
2.Even more difficult to observe, but more important to the understanding of cometary activity and ultimately to the origins of the comets, are the internal physical properties, including the volatilecomposition, dust to gas massratios, and the thermo physical properties of the nucleus: thermal conductivity, pore size, ... I hope this help.
