Astronomy Chapter 8

What relatively recent event shows that impacts continue to happen in our solar system even today?

a comet (which broke into more than 20 pieces) hit the planet Jupiter in 1994

The Van Allen belt is

a region of trapped charged particles in the Earth's magnetosphere

Which of the following is a way we believe that the early atmosphere of the Earth differed from the atmosphere we have today?

a. there was little if any free oxygen early on b. there was no ozone layer early on c. there was probably more carbon dioxide early on than there is today !!!!!!!!!!!!!!d. all of the above!!!!!!!!!!!<<<<

According to the fossil record, how old is the oldest evidence of life forms on the surface of the Earth?

about 3.5 billion years

One way in which the ozone layer is useful for life forms on the Earth's surface is that it

absorbs ultra-violet light, preventing much of it from reaching the surface

If no one has ever visited the core of the Earth, how do we know that it is made of metals?

b. circulating liquid metals in the core set up a large (measurable) magnetic field

Which of the following points about our planet's atmosphere is FALSE? a. it is slowly leaking atoms into space from its outermost regions b. its mass is a substantial part of the mass of the Earth c. warm air rises and cool air descends within it, setting up circulating currents ` d. it is made mostly of nitrogen e. one of its layers helps keep much of the ultraviolet radiation from space from reaching the surface

b. its mass is a substantial part of the mass of the Earth

Any rock in the Earth's crust that has cooled from an originally molten state is called

c. igneous

33. Which of the following is NOT evidence that objects from space collide with the Earth? a. the devastation that happened in 1908 near the Tunguska river in Siberia b. Meteor Crater in Arizona c. the crater at the top of the Mount St. Helens volcano d. the Chicxulub crater buried near Mexico e. you can't fool me; all the above are the results of cosmic impacts

c. the crater at the top of the Mount St. Helens volcano

In which region of the Earth's atmosphere have you spent most of your life?

c. the troposphere

The average temperature on planet Earth is higher than you would expect just from the heating of sunlight alone. What is the explanation for this?

carbon dioxide (and other gases) in the atmosphere cause a greenhouse effect

3. Which part of the Earth has the greatest density?

core

The person who came up with the continental drift theory that led to our modern understanding of plate tectonics was

d. Alfred Wegener

Rocks that have not been chemically modified by being significantly heated are called

d. primitive

Which of the following statements about the Earth's magnetosphere is FALSE? a. it contains particles that come mainly from the solar wind b. it is generated by circulating liquid metal inside the Earth's core c. it was first detected in space by the Explorer 1 satellite d. it extends into space over a region much bigger than the diameter of the Earth e. its shape and size are the same on the sides facing toward and away from the Sun

e. its shape and size are the same on the sides facing toward and away from the Sun

The type of rock we find predominant in the crust of the Earth's continents is called:

granite

2. The largest part of the Earth is its

mantle

An important way that scientists have been able to study the interior of the Earth is by:

measuring how seismic waves are transmitted through the Earth

In terms of numbers, the most common life-forms on Earth are

microscopic creatures, too small to see with our eyes

The most abundant gas in Earth's atmosphere is

nitrogen

Earthquake producing faults are much more likely to be found

on the boundaries of continental plates, where they meet other plates

Regions where the continents or the sea floor are pulling apart are called

rift zones

Scientists have been concerned about a set of industrial chemicals called CFC's (chlorofluorocarbons) because they

rise into the atmosphere and destroy ozone

Today, scientists believe that the main reason the Earth has had periodic ice ages is:

slow changes in the tilt of our planet's axis of rotation

According to the theory of plate tectonics,

slow motions within the mantle of the Earth move large sections of the crust around

The Moon is heavily cratered, but the Earth which "lives next door" is NOT. Why?

the active geology and weather on Earth destroy traces of impacts over millions of years

For scientists, one bar is

the average height of the ozone layer above the Earth (before we began to deplete it)

In 1980, scientists suggested that the great mass extinction of 65 million years ago (which ended the reign of dinosaurs) may have been caused by a large impact from space. What discovery gives a big boost to this idea?

the discovery of a buried crater (about 200 km across) near Chicxulub, Mexico

Scientists now understand that the Earth consists of layers, with the densest materials in the core. What allowed the differentiation of the Earth's layers to happen?

the early Earth must have been so hot it was like a liquid and heavier things sank to the middle

The region around the Earth where charged particles are trapped and spiral around is called:

the magnetosphere

26. An increase in the Earth's temperature by several degrees Celsius would result in:

the melting of many glaciers, a rise in sea levels, and more flooding of towns near the coasts of the continents

15. The process of convection involves

the slow upward flow of warmer material and downward flow of cooler material

Which of these did the June 1908 impact event in Siberia and the 2013 event in the Russian city of Chelyabinsk have in common?

they both exploded high in the atmosphere and produced a shock wave that reached the ground

A spot where magma rises to the surface can be seen as a

volcano

Today, a significant amount of new gas is joining the atmosphere of the Earth from what source:

volcanoes release gas that was trapped within the Earth

Mountains on Earth often have sharp peaks and edges to them, while mountains on the Moon look smooth and kind of dull in comparison. What gives the Earth's mountains their dramatically sharp shapes?

water and ice flow over the Earth's mountains and erode them