| Recall
what we have determined for planets so far. For example,
Mass. By itself, however, it doesn't
really tell us much about planetary interiors. It simply indicates how much material
a planet contains.
Radius. By itself it doesn't tell us much about
interiors either. It simply indicates how large, spatially, a planet occupies.
Density. Even though density is derived
using mass and radius, density tells us quite a bit about a planet's
interior.
Consider
for example, the mean density of geologic material
Ices |
1.0 gram cm-3 |
| Volcanic Rock |
2.8 - 3.9 gram cm-3 |
| Iron-rich materials |
5.0 - 6.0 gram cm-3 |
| Other metals |
7.9 gram cm-3 |
|
