Astronomy Chapter 7: Earth

What conditions are needed to create a dynamo in Earths interior? What effect does this dynamo have?

Rapid rotation is needed to create a dynamo in Earths interior. Liquid core.

What is the greenhouse effect, and what effect does it have on Earths surface temperature?

Absorbing and trapping infrared radiation makes our planet 40°k warmer.

How do geologists use earthquakes to obtain information about Earths interior?

By how the Earth produces seismic waves and pressure.

Give a brief description of Earth's magnetosphere, and tell how it was discovered. How does the magnetosphere protect us from the harsh realities of interplanetary space?

Charged particle from solar wind trapper.

What process is responsible for surface mountains, oceanic trenches, and other large-scale features on Earths surface?

Collision and sub-duction of Earth's crustal plates. The plates are slowly moving—literally drifting around the surface of our planet. [ These plate motions have created the surface mountains, the oceanic trenches, and the other large-scale features across the face of planet Earth. he process is popularly known as "continental drift." The technical term for the study of plate movement and its causes is plate tectonics.

What is convection? What effect does it have on (a)Earth's atmosphere and (b) Earth's interior?

Convection is the circular movement in a liquid when it is in a non-uniform temperature which is based on gravity and the difference in its density. While convection is generally most noticeable in liquids the same movement applies to gases. In astronomy convection generally refer to the movement of gases due to heat and gravity. This movement involves both the transfer of heat and mass.

Give two reasons geologists think that part of Earths core is liquid.

During earthquakes you can Analyze the seismograph recorded at that place to know the inner parts of earth. The primary wave will pass through liquid. But the secondary wave will get reflected when it touches the liquid surfaces. There are several waves other than P,S,L,& R like pp, ss, ps can be seen in the graph that the seismologist can distinguish.

Is the greenhouse effect operating in Earth's atmosphere helpful or harmful? Give examples. What are the consequences of an enhanced greenhouse effect?

Greenhouse effects in the atmosphere are harmful. When CO2 is released into the atmosphere from the process of burning of gases it heats up the temperature resulting in heat, wave, and increase water level.

By comparison with Earths average density, what do the densities of the water and rocks in Earths crust tell us about Earths interior?

That means the interior of the Earth needs to have density higher than the overall average density of the Earth.

What clue to our planets history does Earths differentiation provide?

The core-mantle-crust structure gives us important clues about the history of the Earth and other planets. First, it shows the importance of differentiation processes - processes that separate materials of different composition from one another.

Explain how the Moon produces tides in Earth's oceans.

The moon and Earth pull on each other through gravity, the Earth is 81 times more massive so mostly the moon get swung around the Earth. However the Earth does get pulled around a bit by the moon, and it's this motion that causes the tides.

How did radioactive decay heat the Earth early in its history? When did this heating end?

The radiation is infrared and heats forever.