6 - survey of our solar system (oct. 24) Sun is the heart of the solar system. Sun"s radiation warms all the objects in the solar system. Sun"s gravity holds the solar system together. But, we will ignore the sun (it is covered in ast201 as the nearest star) to focus on everything else in the solar system. Recall from ch 1, edge of the solar system is about half way to the nearest star - measured using parallax. Edge varies because the sun and the nearby stars move around. This is far beyond pluto or the new dwarf planets ( only about 100 au) or the comets. Planets like earth - terrestrial planets = mercury, venus, earth and mars. Planets like jupiter - jovian planets = jupiter, saturn, uranus and neptune. Large average densities = mass/volume 5 g/cm^3. Note: rock 3 g/cm^3 rock + metals. Large masses: 14. 5 to 318 x earth"s mass.