Scientists think the Earth's core is composed mainly of?
Iron
What evidence indicates that part of the Earth's interior is liquid?
No S-type seismic waves are detectable at some locations after an earthquake.
Scientists use radioactivity in rock samples to measure?
The Earths age
The slow shifts of our planet's crust are believed to arise from?
Heat from the interior causing convective motion, which pushes on the crust
Plate motion at subduction zones can cause?
Earthquakes, Volcanic activity, and the creation of mountains
The presence of a strong magnetic field around a planet like the Earth is evidence for? Rotational and convective motion in a liquid core
Why is carbon dioxide called a "greenhouse gas"?
It absorbs infrared light
True or False - The Coriolis Effect is why the Earth rotates counter-clockwise as seen from above?
False
At what location would a pendulum's direction appear to change the most over a day?
On the ice at the North Pole
The large number of craters on the lunar highlands compared to those on the maria is evidence that?
The maria is much younger than the highlands
What evidence indicates that the Moon lacks a large iron core?
The Moon's average density is about 3.3 grams per cubic centimeter, similar to that of rock
If the Moon did not rotate on its own axis, we would observe?
Both sides of the Moon
The Moon does not undergo plate tectonics because?
Its mantle is cold and rigid
The photographs in figure 7.16 were taken at high tide and the next low tide. About how much time elapsed between the pictures?
Six hours
Which of the following objects are primarily rocky with iron cores?
Mercury, Venus and Earth
One explanation of why the planets near the sun are composed mainly of rock and iron is that?
The suns heat made it difficult for other substances such as ices and gases to condense near it
Which of the following features of the Solar System does the solar nebular theory explain?
All the planets, orbit the sun in the same direction, move in orbits that lie in nearly the same plane, and to the extent that we know, are the same age (including the sun). The planets nearest the sun contain only small amounts of substances that condense at low temperatures
The numerous craters we see on the solid surfaces of so many Solar System bodies are evidence that?
They were bombarded in their youth by many solid objects
The Doppler-shift method for detecting the presence of exoplanets is best able to detect?
Massive planets near the star
The transit method for detecting exoplanets works best for?
Solar Systems seen edge- on
Why does Mercury have so many craters and the Earth so few?
Erosion and plate tectonic activity have destroyed most of the craters on the Earth
Mercury's average density is about 1.5 times greater than the Moon's, even though the two bodies have similar radii. What does this suggest about Mercury's composition?
Mercury's interior is much richer in iron than the Moon's
Why is Venus's surface hotter than Mercury's?
Carbon dioxide in Venus's atmosphere traps heat radiating from its surface, thereby making it warmer
What are the Venusian clouds made of?
Sulfuric acid droplets
Astronomers can measure the time since the last eruption of a volcano on Mars by?
Counting the number of craters on its slope
Why is there no liquid water on the surface of Mars today?
The atmospheric pressure is so low, any liquid water would immediately evaporate
Which body in the inner Solar System has the densest atmosphere?
Venus
Which of the following features are shared by all of the terrestrial planets?
An iron core
The low average densities of Jupiter and Saturn compared with the Earth's suggest that?
Jupiter and Saturn contain large quantities of light elements, such as hydrogen and helium
Astronomers think that the inner core of Jupiter is composed mainly of?
Rock and iron
Why would it be foolish to send astronauts to land on Jupiter?
It has no solid surface for them to land on
What is the Roche limit?
The smallest mass a planet can have and still be composed of mainly hydrogen
What source of energy allows Jupiter and Saturn to radiate more heat than they receive from the Sun?
Gravitational energy of sinking material
What makes some astronomers think that Uranus was hit by a large body early in its history?
Its rotation axis has such a large tilt
Like the other gas giants, Neptune's rotational period is closest to 2/3rds of an Earth?
Day
Which of the following are reasons why we don't have a picture of Pluto?
We have not yet seen a mission to Pluto and its angular size is too small for even the Hubble Space Telescope to get a clear image of it
The bright streak of light we see as a meteoroid enters our atmosphere is caused by?
Frictional heating as the meteoroid speeds through the gases of our atmosphere
Meteor showers such as the Perseids in August are caused by?
The Earth passing through the debris left behind by a comet as it moves through the inner Solar System
Meteoroids originate from?
Comet debris, material left over from the formation of the Solar System, asteroids, material blasted off other planets in collisions
The asteroid belt lies between the orbits of?
Mars and Jupiter
Asteroids in the asteroid belt are made up of?
Iron, silicates (rock), and organic compounds in amounts that vary depending on where they orbit (and were formed)
The tail of a comet?
Always points away from the Sun and is gas and dust expelled from a comet's nucleus by the Suns heat and radiation pressure
Astronomers think that most comets come from?
Small icy bodies in the extreme outer parts of the Solar System that are disturbed into orbits that brings them closer to the Sun
Short period comets have a life period of around?
Decades to a few hundred years
Short period comets mostly come from the?
Kuiper belt
A moving object's kinetic energy depends on its?
Velocity and Mass
Strong evidence that the dinosaurs were killed by a meteor impact is provided by?
Mass extinctions 65 million years ago, an unusually rich layer of a rare element in the rock record at 65 million years ago and a layer of 65 million year old soot in the rock record
As a result of the Moons gravitational pull, when would you weigh the least?
