Density

The figures show the internal structures of the Earth and the Moon today, as well as the best estimates of their average densities, inferred and calculated from rock samples and seismic data (measurements of ground vibrations). Earth’s core is about 30 percent of its mass, while the Moon’s core is only about 1 to 2 percent of its mass. Note that density data for the Moon is more uncertain than that for Earth.

Click to view larger image

Note: Not to scale. The Moon is approximately 27 percent the width of Earth.

Take Notes

Explain whether data about the density of Earth and the Moon supports the giant impact hypothesis. Make connections between the density of the Moon’s crust and mantle and the nature of the impact as shown in the simulation on page 2.