ASTR 7

What makes Earth unique among terrestrial worlds?

Earth has oceans, a nitrogen-oxygen atmosphere, and life.

What characteristics must Earth's core have to generate a magnetic field?

The core must be convecting, rotating, part liquid, and the material must be conductive.

How do island chains like the Hawaiian-Emperor chain indicate ongoing tectonic plate activity?

Island chains are created by a plate moving over an upwelling lava source.

What produced the oxygen in Earth's atmosphere?

Oxygen was produced by plants.

Is the greenhouse effect harmful to Earth's climate?

False, without the greenhouse effect, Earth would be colder and unsuitable for water-based life.

What are Earth's core and mantle primarily made of?

The mantle is made of rock, and the core is primarily made of iron and nickel.

How do we know the composition of Earth's core and mantle?

We analyze seismic waves, conduct chemical analysis of volcanic samples, and use our understanding of planetary formation.

What is the most abundant component of Earth's atmosphere?

Nitrogen (N2).

Briefly describe the greenhouse effect.

Sunlight is absorbed by Earth's surface and reemitted as infrared radiation, which greenhouse gases absorb, raising the planet's surface temperature.

What explains why the average temperature on Earth is higher than expected from sunlight alone?

Carbon dioxide and other gases in the atmosphere cause a greenhouse effect.

What distinguishes Earth's inner core from its outer core?

The inner core is solid, while the outer core is liquid.

What creates Earth's strong magnetic field?

Convection in Earth's outer liquid iron-nickel core combined with Earth's rotation.

Where on Earth are two tectonic plates being pushed apart and new crust created?

Along the center of the Atlantic Ocean and along the center of the Red Sea.

What is the likely source of Earth's early atmosphere consisting of carbon dioxide and water vapor?

It was outgassed from Earth's interior during volcanic activity and arrived via icy planetesimals.

What happened to the majority of the carbon dioxide that was formerly in Earth's atmosphere?

Most of it dissolved into the oceans and is now in the form of rocks such as limestone.

In what order did carbon dioxide and oxygen occur in Earth's atmosphere?

Oldest: carbon dioxide; Youngest: oxygen.

Rank the atmospheric gases in order of their abundance in Earth's current atmosphere.

Most: nitrogen; Middle: oxygen; Least: carbon dioxide.