chapter 8 Flashcards
(25 cards)
The nucleus of a typical comet is:
- irregular in shape, with a bright and very reflective, icy surface.
- spherical, with a very smooth, dark surface.
- irregular in shape, with a very dark and cratered surface.
- spherical, smooth, and very light-colored, being composed mostly of ice.
irregular in shape, with a very dark and cratered surface
How does the dust tail of a comet compare with its gas tail?
-Dust tails often appear blue and gas tails white.
- Dust tails are straight, whereas gas tails are curved.
- Dust tails are more massive than gas tails.
- Dust tails point toward the Sun, whereas gas tails point away.
Dust tails are more massive than gas tails.
An asteroid is:
- a small, easily recognizable group of stars within a constellation.
- a planetesimal moving in an orbit around the Sun.
- another name for the nucleus of a comet, a volatile object that moves around the Sun in a long, elliptical orbit.
- a meteorite before it enters the atmosphere and plunges to Earth.
a planetesimal moving in an orbit around the Sun.
Which object in the solar system has the greatest orbital inclination (orbit at the greatest angle to that of Earth)?
- Mercury
- Mars
- Jupiter
- Pluto
Pluto
Where do the Trojan asteroids orbit the Sun?
- in circular orbits at the same orbital distance as Jupiter
- in circular orbits at the same orbital distance as Earth
- in the asteroid belt, so-named because they are large
- in elliptical orbits that cross the orbit of Earth
in circular orbits at the same orbital distance as Jupiter
The asteroid belt is believed by most astronomers to be composed of:
- rocky debris left over from the formation of the solar system.
- genuine leather.
- rather dirty ice balls similar to the nuclei of comets.
- the remnants of a gaseous planet disrupted by a massive impact.
rocky debris left over from the formation of the solar system.
Stony-iron meteorites are believed to:
- have been ejected by volcanoes on Mars.
- originate from differentiated asteroids (in which iron sank to the center).
- be pieces of primordial solar system material, unaltered since the solar system formed.
- originate from undifferentiated asteroids (same composition throughout).
originate from differentiated asteroids (in which iron sank to the center).
A piece of rock from outer space that reaches Earth’s surface after surviving a fiery passage through Earth’s atmosphere is known as a(n):
- meteoroid.
- asteroid.
- meteor.
- meteorite.
meteorite.
The orbits of comets are:
- primarily in the plane of the ecliptic and can extend far out beyond the orbit of Pluto.
- randomly oriented in the solar system and confined to distances closer to the Sun than approximately the orbit of Pluto.
- primarily in the plane of the ecliptic and confined to distances closer to the Sun than approximately the orbit of Pluto.
- randomly oriented in the solar system and can extend far beyond the orbit of Pluto.
randomly oriented in the solar system and can extend far beyond the orbit of Pluto.
Stony meteorites:
- are very much like ordinary silicate rocks.
- contain large quantities of carbon and water and even hydrocarbons and amino acids.
- have solid iron cores surrounded by rocky silicate shells.
- are made of solid iron and small quantities of nickel and cobalt.
are very much like ordinary silicate rocks.
A meteor shower results from:
- material ejected by a massive impact on the Moon; Earth’s gravity attracts it toward Earth.
- material reentering Earth’s atmosphere after being ejected into space by violent volcanic eruptions on Earth.
- Earth passing through debris of an old comet.
- a small piece of rock fragmenting as it passes through Earth’s atmosphere.
Earth passes through debris of an old comet.
What effect does Jupiter have on asteroids in the asteroid belt?
- Jupiter has no effect whatsoever on such small objects because they are a long way away from Jupiter, and Jupiter’s gravitational influence varies as the inverse square of distance, by Newton’s law.
- Jupiter perturbs only the orbits of asteroids whose orbital periods are a simple fraction (e.g., 1/2, 1/3, 2/3, 2/7) of its orbital period.
- Jupiter disturbs only the orbits of asteroids whose orbital distances (or semimajor axes) are a simple fraction (e.g., 1/2, 1/3, 2/3, 2/7) of the radius of Jupiter’s orbit.
- Jupiter disturbs the orbits of all the asteroids in the belt, slowing them down and causing them to spiral slowly in toward the Sun.
Jupiter perturbs only the orbits of asteroids whose orbital periods are a simple fraction (e.g., 1/2, 1/3, 2/3, 2/7) of its orbital period.
The Oort cloud is:
- a random distribution of short-period comets extending from inside the orbit of Jupiter to approximately the orbit of Neptune.
- another name for the asteroid belt.
- a flat or donut-shaped distribution of distant comets around the Sun, extending out about 500 AU.
- a spherical distribution of distant comets around the Sun, extending out about 50,000 AU.
a spherical distribution of distant comets around the Sun, extending out about 50,000 AU.
Which are the MOST common types of meteoroids in space?
- stony-irons
- stones
- irons
- carbonaceous chondrites
stones
The ionized gas tail of a comet is always aligned along the:
- comet-Sun line.
- line between the comet and the nearest planet to it in its orbital motion.
- comet’s direction of motion.
- celestial equator.
comet-sun line
Asteroids whose orbits carry them across Earth’s orbit are known as:
- Kirkwood asteroids.
- Amor asteroids.
- Trojan asteroids.
- Apollo asteroids.
Apollo asteroids.
What is the LARGEST known asteroid in our solar system?
- Phobos
- Gaspra
- Ceres
- Pallas
Ceres
Dust grains released by the melting of ice in a comet nucleus:
- drift away from the Sun along magnetic field lines, outlining the structure of the field.
- become a straight, highly structured, and very variable tail blown away from the comet by the solar wind.
- become a cloud around the nucleus, the coma, scattering sunlight very efficiently at blue wavelengths.
- become a uniform, curved tail moving away from the comet under radiation pressure from sunlight.
become a uniform, curved tail moving away from the comet under radiation pressure from sunlight.
A comet’s tail always:
- points toward the nearest planet, attracted by the planet’s gravity field as the comet passes by the planet.
- trails behind the comet in its orbit and so points away from the Sun only while the comet is approaching the Sun.
- points away from the Sun, regardless of the motion of the comet.
- points toward the Sun because the tail is caused by jets of gases evaporated from the comet’s nucleus on the side heated by the Sun.
points away from the Sun, regardless of the motion of the comet.
The Kirkwood gaps are caused by:
- large asteroids moving in circular orbits within the asteroid belt, which sweep out and collect smaller objects in their path.
- large asteroids whose orbits carry them periodically through the asteroid belt, where they sweep out a path and leave it devoid of asteroids.
- the gravitational pull of Jupiter, which nudges asteroids into new orbits.
- large asteroids on the outer fringe of the asteroid belt, which gravitationally affect the paths of smaller objects within the belt.
the gravitational pull of Jupiter, which nudges asteroids into new orbits.
A shooting star is a:
- violently erupting star ejecting matter rapidly away from it into interstellar space.
- near-neighbor star moving rapidly across our field of view.
- leading scorer on a basketball team.
- small particle of interplanetary dust burning up and glowing as it enters Earth’s atmosphere.
small particle of interplanetary dust burning up and glowing as it enters Earth’s atmosphere.
The asteroid belt exists between the orbits of the planets:
- Earth and Mars.
- Jupiter and Saturn.
- Venus and Earth.
- Mars and Jupiter.
Mars and Jupiter.
Meteoroid is the term used to describe a solid particle that:
- is drifting around in space.
- has fallen to Earth from space.
- burns up as it falls through Earth’s atmosphere.
- originated on the Moon but was knocked onto Earth by a massive impact.
is drifting around in space.
What is unusual about the surface of Haumea?
- It is solid rock.
- It appears to be a mixture of rock and ice.
- It is almost pure water ice.
- It is almost perfectly round.
It is almost pure water ice.
