Chapter 16: The Earth and Moon (Study Questions) – Flashcards

The Earth is unique among the Terrestrial planets because it has liquid water on its surface and life that is aware living on it.

see pages 361 - 363

The density of the surface rocks is lower than the overall density of the Earth. Therefore, the more dense rocks must be in the interior.

At least part of the core must be liquid and it must be in motion to produce electrical currents, which in turn produce the magnetic field.

Photosynthetic plants multiplied to the point that they produced more oxygen than was being taken out of the atmosphere by chemical reactions.

Carbon dioxide molecules absorb infrared radiation and then re-emit that radiation in random directions. There are enough carbon dioxide molecules in the atmosphere for much of that infrared radiation to be emitted back toward the Earth, which warms the Earth. The Earth now has two heat sources: the Sun and its own atmosphere.

The ozone molecule, consisting of three oxygen atoms, is very good at absorbing ultraviolet radiation. A thinner layer of ozone would absorb less ultraviolet light. As ultraviolet light has enough energy to disrupt the cells normal processes and cause the cell to become cancerous, there would be more skin cancers.

Earth has an atmosphere dense enough for water to be in the liquid state when the temperature is above the freezing point of water. Therefore, the surface of the Earth is subjected to both wind and water erosion. Also, Earth is undergoing plate tectonics so the crust is being covered with lava or it undergoes subduction and is melted to become part of the mantle.

Erosion by micrometeorites is the main cause of erosion on the Moon now.

P-waves are pressure waves and cause the ground to compress and uncompress, like sound traveling through air. P-waves can travel through liquids. S-waves are shear waves and cause the ground to move side-to-side, like a vibrating cube of Jell-O becoming a solid with parallelograms for sides (parallelepiped) and back again. S-waves cannot travel through liquids. By examining the seismographs at different locations around the globe during an earthquake, geologists can see where there are P-waves and no S-waves, concluding that at least part of the interior is liquid. Where there are both P-waves and S-waves, they have been refracted differently by the different layers so geologists can get an idea of where boundaries are for the different layers interior to the Earth.

The "dynamo effect" is when electrically charged currents of material flows to form magnetic fields. This occurs in Earth's liquid outer core.

The majority of the craters on the Moon where formed by the impact of material (meteorites, asteroids, etc.).

The maria have fewer craters than the highlands so they must be younger.