Chapter 15: Vagabonds of the Solar System
Which is closest to the average distance between asteroids in the asteroid belt?
1 million km
The typical size of a comet's nucleus is about _____.
10 km
A typical asteroid has an orbital period around the sun of 5.2 years. How far from the sun is this asteroid?
3.0 AU
The Trojan asteroids orbit the Sun at an average distance of ____
5.2 AU
Which of the following asteroids is now officially a dwarf planet?
Ceres
The Apollo asteroids is a group of asteroids that _______.
Cross the Earth's orbit
When we see a meteor shower, it means that
Earth is crossing the orbit of a comet.
How is the coma of a comet produced?
Ices vaporize to become gas that form the coma around the comet.
How does the largest asteroid, Ceres, compare in size to other solar system worlds?
It is about a quarter the size of the Moon.
Planet __________ creates the gaps in the asteroid belt called Kirkwood gaps.
Jupiter
Radiant is a common point from which the/a __________ seem/s to diverge.
Meteor shower
Which of the following is evidence for the connection between comets and meteor showers?
Meteor showers are an annual event. Many of these are known to be when the Earth crosses a comet's orbit.
The fragments that do not completely burn in the atmosphere and eventually fall on the Earth are called
Meteorites
The Perseid meteor shower appears to come from
a point in the constellation Perseus
What is a meteorite?
a rock from the solar system that has fallen to Earth's surface
Where are the Trojan asteroids located?
along Jupiter's orbit, 60° ahead of and behind Jupiter
A(n) ____ is a stony meteorite that contains no chondrules and no volatiles. They appear to have been melted after they formed and resemble solidified lavas.
anchondrite
The largest asteroids in the asteroid belt, such as Ceres
are rocky and roughly spherical because their gravity pulled them into this shape when they once were molten.
The largest asteroids in the asteroid belt, such as Ceres,
are rocky and roughly spherical because their gravity pulled them into this shape when they once were molten.
Halley's comet is named after the English scientist Edmund Halley because he
calculated its orbit and predicted that it would return in 1758.
The Trojan asteroids share Jupiter's orbit and are strongly influenced by the gravity of both the Sun and Jupiter. They have orbital periods that are
close to Jupiter's period
When a comet passes near the Sun, part of it takes on the appearance of a large, bright ball from which the tail extends. This part is called the
coma
A meteor shower occurs when the left-over debris of a _______ intersects with our atmosphere to produce the beautiful streaks of light.
comet
The Widmanstätten patterns found in some meteorites show that the material
cooled very slowly
We know that there are large gaps in the average distances of asteroids from the Sun (within the asteroid belt) because we
have plotted distributions of the orbital radii of the asteroids.
Halley's comet is named after the English scientist Edmund Halley (1656-1742) because
he calculated its orbit and predicted the year in which it would next be seen.
Comet tails appear only when a comet moves into the inner solar system. This is because
heat from the Sun causes ices on the comet to vaporize.
Iron meteorites are easier to find on the surface of the Earth than stony meteorites because
iron meteorites are easier to distinguish from rocks on Earth's surface.
If a large 10-km asteroid or comet struck the Earth in the ocean floor,
large amounts of molten rock would rain down on Earth and cause massive forest fires. thick clouds of dust would form and block out the sun for an extended period. giant tidal waves would result after effects would cause the deaths of most animal life on the planet.
The combined mass of all the asteroids in the asteroid belt is
less than that of any terrestrial planet.
A bit of matter that enters Earth's atmosphere and survives to reach the ground is called
meteorite
What do we call a small piece of solar system debris found on Earth?
meteorite
__________are pieces of rock, _________ are pieces of rock that burns up in Earth's atmosphere, and _________ are pieces of rock that actually reaches Earth's surface.
meteoroids, meteors, meteorites
Stony, chondrite, achondrite, and stony-iron meteorite types are classified according to their
mineral content
A typical meteor is created by a particle about the size of a
pea
A typical shooting star in a meteor shower is caused by a ________ entering Earth's atmosphere.
pea-size particle from a comet
The gas tail of a comet always
points away from the sun.
The trail you see behind a meteor as it moves across the sky is due to
rocky material of the meteor burning up due to interaction with the Earth's atmosphere.
When you see the bright flash of a meteor, what are you actually seeing?
the glow from a pea-size particle and the surrounding air as the particle burns up in our atmosphere
If a large 10-km asteroid or comet struck the Earth in the ocean floor
thick clouds of dust would form and block out the sun for an extended period. large amounts of molten rock would rain down on Earth and cause massive forest fires. after effects would cause the deaths of most animal life on the planet. giant tidal waves would result
