Astronomy Chapter 4 (The Solar System)

In terms of composition A) the terrestrials are more like the Sun, since they formed close to it. B) the jovian planets are made only of ice, and the terrestrials only of rock. C) the Sun is unique, made of nothing but hydrogen and helium. D) the jovian planets are more like the Sun than are the terrestrials. E) all planets condensed from the same nebula, and have similar compositions.

D

Iron meterorites are believed to come from A) the crust of a differentiated asteroid, now broken up. B) interstellar space. C) debris from the Kuiper Belt. D) the core of a differentiated asteroid, now broken up. E) a broken up cometary nucleus.

D

The smallest planet, Mercury, has no moons.

True

We should expect other planets beyond our own solar system to orbit the equators of their home stars, as our own planets orbit the Sun.

True

The process by which small debris condenses into planetesimals is ________.

accretion

A rocky body between the orbits of Mars and Jupiter is a(n) ________.

asteroid

The ________ is the spherical outgassing as a comet nucleus is heated by the Sun.

coma

Meteoric material dates the formation of the solar system at about ________ billion years.

4.6

A meteor is A) a streak of light in the atmosphere. B) an irregularly shaped body, mostly found orbiting between Mars and Jupiter. C) an icy body with a long tail extending from it. D) a chunk of space debris orbiting the Earth. E) a chunk of space debris that has struck the ground.

A

As the solar nebula contracts, it A) spins faster due to conservation of angular momentum. B) cools due to condensation. C) loses angular momentum. D) flattens out into the ecliptic plane around the Sun's poles. E) reverses its direction of rotation.

A

Meteorites are important because A) large ones may cause mass extinctions. B) they contain pristine material from the solar nebula. C) some come from the Moon and Mars, as well as the asteroid belt. D) All of the above are true. E) None of the above are true.

D

Meteor showers are the result of collisions between asteroids.

False

One characteristic of the terrestrial planets is their extensive moon systems.

False

Pluto's orbit has a lower inclination to the ecliptic than any planet or dwarf planet.

False

The Oort Cloud lies closer to the Sun than the Kuiper Belt.

False

The only planet with no atmosphere of consequence is ________.

Mercury

All the terrestrial planets lie inside the asteroid belt.

True

Any successful model for the formation of the solar system must explain why the orbits of the planets have low eccentricities.

True

As a rotating gas cloud contracts, it spins faster.

True

Barringer Crater in Arizona is an example of a meteorite impact.

True

Carbonaceous asteroids contain fragile organic molecules.

True

Cometary dust tails lag behind the bluish ion tails as the comet rounds the Sun.

True

In addition to revolving around the Sun counter clockwise, most planets also rotate on their axis counter clockwise.

True

In some cases, we have seen extrasolar planets pass in front of their stars.

True

In the solar nebular theory, the dusty disk condensing around the Sun's equator became the ecliptic plane in which the planets then formed.

True

Most astronomers now believe the demise of the dinosaurs 65 million years ago was caused by a large asteroid impacting the Yucatan peninsula area.

True

Most astronomers now regard Pluto as just one of the largest of the thousands of Kuiper Belt bodies found beyond Neptune.

True

Pluto is more similar to the jovian planet's icy moons than to any of the other planets

True

Researchers estimate that there is more total mass in the Kuiper Belt than in the asteroid belt.

True

Some meteorites are believed to have come from Mars and the Moon.

True

The curved, yellow ________ tail lags behind the blue tail as the comet rounds the Sun.

dust

All planets lie in orbits close to the ________ plane.

ecliptic

The solar nebular theory has been supported by observation of dusty disks around the ________ of young, condensing stars.

equators

The second most abundant element in the solar system is ________.

helium

Comet orbits all have ________ eccentricity compared to the asteroids.

high

Most of the planets found orbiting other stars are similar to Jupiter, but ________ in temperature.

hotter

While Kuiper Belt bodies are often larger than any asteroid, we think their density will be lower due to presence of a lot of ________.

ice

A solid body from the outer solar system that arrives intact on the Earth's surface is called a ________.

meteorite

Streaks of light made when small debris hits our atmosphere are called ________.

meteors

The age of the solar system is determined with ________ dating.

radioactive

The terrestrial planets have mantles of ________ materials and iron rich cores.

rocky

A body in orbit about a planet is a ________.

satellite

In composition, the ________ planets have rocky materials like the asteroids.

terrestrial

Comets are not actually members of the solar system, but captured by the Sun.

False

Due to their great masses, all four Jovian worlds are much denser than the earth.

False

Earth is nearly twice as large as Venus.

False

All four jovian planets are thought to have cores larger than Earth.

True

All jovian planets have rings around their equators and at least eight moons.

True

Which of the following have an icy composition? A) comets B) most asteroids C) meteorites and most asteroids D) the surface of Mars E) meteroids

A

Which statement about asteroids is not true? A) their images become blurry due to outgassing as the Sun heats them up. B) Most stay between the orbits of Mars and Jupiter. C) They vary considerably in composition, reflectivity and size. D) Earthgrazers can cross not only our orbit, but even those of Venus and Mercury. E) Some have satellites of their own.

A

According to the Solar Nebula theory, planets A) will revolve opposite the star's rotation. B) should be a common result of star formation. C) should orbit perpendicular to their star's equator. D) should be extremely rare. E) should be randomly oriented to their star's equator.

B

As a rotating gas cloud contracts, it spins A) slower due to conservation of angular momentum. B) faster due to an increase in angular momentum. C) at a constant rate. D) faster due to conservation of angular momentum. E) slower due to a decrease in angular momentum.

B

Before it arrived in orbit about Eros, the NEAR spacecraft also visited A) Mars. B) the asteroid Mathilde. C) the Moon. D) the asteroid Gaspra. E) Venus.

B

Density is defined as A) weight divided by the planet's radius. B) mass per unit volume. C) mass times weight. D) size divided by weight. E) weight per square inch.

B

Planetary transits of exoplanets are rare because A) the Earth's atmosphere interferes with our observations of transits. B) most extrasolar systems are not seen edge-on. C) most stars are too bright for us to detect a planetary transit. D) most exoplanets are smaller than Pluto. E) our telescopes are not powerful enough to detect them.

B

The Kuiper Belt is found where in the solar system? A) between the orbits of Jupiter and Uranus B) beyond the orbit of Neptune C) among the orbits of the terrestrial planets D) between the orbits of Mars and Jupiter E) sixty degrees ahead or behind Jupiter

B

The largest asteroid, and probably the only one to be a spherical "world" is A) Gaspra. B) Ceres. C) Ida. D) Vesta. E) Eros.

B

The orbits of most comets A) are like planets, fairly circular and in the ecliptic plane. B) lie almost entirely beyond the orbit of Neptune. C) are shorter than the 76-year period for Comet Halley. D) go no further out than Pluto, then return to the sun again. E) have no perihelions within the orbits of Mercury.

B

What is true about solar system densities? A) Planetary density increases with increasing distance from the Sun. B) The denser planets lie closer to the Sun. C) The asteroids all have about the same density. D) In differentiated bodies, the denser materials lie near their surface. E) Saturn has the same density as water.

B

Which planet by itself contains the majority of mass of all the planets? A) Venus B) Jupiter C) Saturn D) the Earth E) Uranus

B

A meteorite is A) a streak of light in the atmosphere. B) an icy body with a long tail extending from it. C) a chunk of space debris that has struck the ground. D) an irregularly shaped body, mostly found orbiting between Mars and Jupiter. E) a chunk of space debris orbiting the Earth.

C

Long-period comets are believed to originally come from A) the Kuiper Belt B) the interstellar medium. C) the Oort cloud. D) the asteroid belt. E) the satellite system of Jupiter.

C

Objects in the Kuiper belt A) are the sources of long-period comets. B) are dense, like the iron meteorites. C) lie beyond the orbit of Neptune, and close to the ecliptic. D) lie beyond the orbit of Neptune, and perpendicular to the ecliptic. E) are in random orbits at all inclinations to the ecliptic.

C

Relative to the comet, the direction of the ion tail tells us A) the direction the comet is traveling. B) the velocity of the comet. C) the direction of the Sun. D) where the ecliptic is. E) where the comet came from.

C

So far, beyond the solar system the extrasolar planets found have been mostly A) large jovians orbiting solar-type stars about where our jovians are found. B) terrestrials with very elongated, distant orbits like comets. C) large jovians very close to their star. D) brown dwarfs much more massive than Jupiter. E) terrestrials very close to their star, and transiting its disk.

C

The Trojan asteroids are found A) orbiting around the Kuiper Belt body Hector. B) closer on average to the Sun than is the Earth. C) sixty degrees ahead or behind Jupiter, sharing its orbit about the Sun. D) beyond Neptune, with orbits similar to Pluto's. E) with the others, between Mars and Jupiter; their red color gives them their name.

C

The first spacecraft to land on the surface of an asteroid was named A) Galileo. B) Dawn. C) NEAR. D) Giotto. E) Stardust.

C

The nucleus of a comet is typically A) very durable, made of iron. B) a few meters in diameter. C) a few kilometers in size, and very low in density. D) located between the orbits of Mars and Jupiter. E) a few hundred kilometers across, and bright, shiny white from its ices.

C

Which of the following is not icy in composition? A) most jovian satellites B) comet nuclei C) asteroids D) Kuiper Belt Objects E) the polar cap of Mars

C

If a comet's ion tail is pointing perpendicular to its direction of travel, the comet is A) close to or at aphelion. B) moving closer to the Sun. C) A comet's tail never points perpendicular to its motion. D) close to or at perihelion. E) moving away from the Sun.

D

Most of the extrasolar planets found so far were detected by A) detecting the oxygen in their atmospheres spectroscopically. B) noting the drop in the star's light as the planet transits its disk. C) imaging them with the HST in the infrared, where they are easier to stop. D) noting the Doppler shifts of the star as the planet orbits it from side to side. E) receiving radio transmissions from them, much like Jupiter emits.

D

Planetary orbits A) have the Sun at their exact center. B) are highly inclined to the ecliptic. C) are evenly spaced throughout the solar system. D) are almost circular, with low eccentricities. E) are spaced more closely together as they get further from the Sun.

D

The Oort Cloud is believed to be A) the circular disk of gas around the Sun's equator from which the planets formed. B) the great nebula found just below the belt stars of Orion. C) a grouping of asteroids and meteoroids between the orbits of Mars and Jupiter. D) a spherical cloud of cometary nuclei far beyond the Kuiper Belt. E) a flattened belt of cometary nuclei just beyond the orbit of Neptune.

D

The larger terrestrial planets have surface features that tend to be A) more rocky. B) more cratered. C) more icy. D) younger. E) older.

D

The most detailed look we've had of an asteroid comes from A) ground based optical images. B) ground based radar images. C) Earth orbital X-ray images. D) spacecraft sent to an asteroid. E) high-altitude UV spectroscopy.

D

The most distant objects in our solar system are A) in the Kuiper Belt. B) the Trojan asteroids. C) the jovians. D) in the Oort Cloud. E) short period comets.

D

The tail of a comet always points A) in the direction of the comet's motion. B) toward Earth and never varies. C) toward the Sun and disappears at perihelion. D) away from the Sun and becomes longest and brightest at perihelion. E) away from the Sun and disappears at perihelion.

D

Which of the following does not fall into the category of interplanetary debris? A) comets B) meteoroids C) Kuiper Belt bodies D) rings around the jovian planets E) Trojan asteroids

D

Which of these bodies are most likely to break up over time? A) Trojan asteroids B) jovian satellites C) asteroids in the main belt D) comet nuclei E) Kuiper Belt bodies

D

The extrasolar planets are found mainly by observing the ________ shifts of their stars.

Doppler

Before it arrived in orbit about Jupiter, the Galileo spacecraft flew past A) Saturn. B) Comet Halley. C) the asteroid Ceres. D) Mars. E) the asteroid Gaspra.

E

Meteor showers are A) usually annual events, as the orbits again intersect. B) caused by the Earth passing near the orbit of an Earthgrazing asteroid. C) caused by the Earth passing near the orbit of an old short-period comet. D) Both A and B are correct. E) Both A and C are correct

E

The Manicouagan reservoir near Quebec is an example of A) cometary debris. B) a volcanic event. C) Earth's interaction with a comet's dust tail. D) a micrometeorite impact. E) a large meteorite impact.

E

The jovian planets A) all spin slower than Earth. B) lie less than 5 AU from the Sun. C) have satellite systems with less than 4 moons. D) are all much more dense than any of the terrestrial planets. E) all have rings around their equators.

E

Which of the following are the jovian planets? A) only Jupiter and Saturn B) only Jupiter C) Jupiter, Saturn, Uranus, Neptune, and Pluto D) everything past Mars and the asteroid belt E) Jupiter, Saturn, Uranus, and Neptune only

E

The NEAR spacecraft actually landed on the asteroid ________ in February 2001.

Eros

All the planet's orbits are evenly spaced.

False

All the planets orbit the Sun in exactly the same plane as the Earth.

False

All the planets revolve around the Sun in the same direction, except for Venus and Uranus.

False

Astronomers have not yet been able to detect planets outside our solar system.

False

All ________ planets have rings around their equators.

Jovian

The ________ planets are large bodies in the outer solar system with compositions like the Sun's.

Jovian

Most asteroid orbits lie between those of Mars and ________.

Jupiter

The ________ Belt bodies orbit beyond Neptune, but like the planets stay close to the ecliptic plane and in fairly circular orbits.

Kuiper

The ________ is a vast, spherical array of long period comet nuclei far beyond the orbit of Neptune.

Oort Cloud

________ is the only planet with a mean density less than water.

Saturn

The asteroids moving in the orbit of Jupiter, but 60 degrees ahead or behind it, are called the ________.

Trojan asteroids

A Kuiper Belt object was discovered that may be larger than Pluto.

True