Astronomy Lecture 11- Comets, Asteroids, Kuiper Belt Objects

A comet that has a semi-major axis of 100 AU must have a period of about 20 years. 10 years. 1,000 years. 100 years.

1,000 years.

On average, a body 100 meters in diameter or larger impacts the Earth every ____ years. 1,000 10,000 one million 10 million 100,000

10,000

At its closest approach, a particular comet is about half an AU away from the Sun, and it's about 40 AU away at its farthest point. The semi-major axis of the comet's orbit is about 40 AU 1/2 AU 20 AU 60 AU

20 AU

The Trojan asteroids orbit the Sun at an average distance of _________. 60 behind 60 ahead 5.2 AU 100,000,000 miles

5.2 AU

What is the difference between a meteor and a meteorite? A meteorite is a very tiny meteor. A meteorite is the flash of light in the sky. A meteor is the solid body ending up on the ground. A meteorite comes from a comet. A meteor comes from an asteroid. A meteor is the flash of light in the sky. A meteorite is the solid body ending up on the ground. A meteorite is the pit made on the Earth or a planet when a meteor hits.

A meteor is the flash of light in the sky. A meteorite is the solid body ending up on the ground.

The Leonid meteor shower occurs in mid-November. Which of the following statements regarding the Leonids is true? All of these choices are correct. The radiant of the meteor shower is in the constellation of Leo. The shower is best observed very early in the morning, before dawn. The shower occurs when the Earth crosses the path of an old comet.

All of these choices are correct.

What evidence do we have that an impact played a role in the extinction of the dinosaurs? The dinosaurs, as well as large numbers of other animals and plants, disappeared rather suddenly. All of these choices are correct. There is iridium (rare on Earth, but abundant in meteors) and soot (evidence of widespread fires) in a layer of clay laid down 65 million years ago. Astronomers have found evidence for a 65-million-year-old impact crater in the Yucatàn.

All of these choices are correct.

omets are rich in __________. water carbon dioxide (CO2) carbon monoxide (CO) All of these choices are correct.

All of these choices are correct.

Which of the following asteroids is now officially a Dwarf Planet? Ida Methilde Eros Ceres Itokawa

Ceres

_____ travel(s) the farthest from the Sun. Comets Pluto Charon Asteroids

Comets

Which spacecraft launched a probe that smashed into comet Tempel 1? NEAR Stardust Hayabusa Deep Impact

Deep Impact

Which Trans-Neptunian Object is largest in diameter? Makemake Orcus Pluto Sedna Eris

Eris

Some asteroids have peculiar orbits that do not obey Kepler's laws. True False

False

The existence of amino acids in carbonaceous chondrites proves that life on Earth originated in space. True False

False

What is a useful result of the discovery that Charon occasionally eclipses Pluto? It allowed astronomers to measure the distance between Pluto and Charon. It allowed astronomers to image surface features of Pluto. It showed that eclipses occur in other parts of the Solar System. It allowed astronomers to determine the size of Pluto and Charon more accurately.

It allowed astronomers to determine the size of Pluto and Charon more accurately.

Why can a rather small meteorite make such a big crater when it hits? Meteorites are much harder than the surface of the planet, and punch through it easily. Air pressure on the leading side of the meteorite forms a shock wave that blows out the crater. It is traveling so fast that it has a very large kinetic energy even with small mass. It is so hot from its passage through the air that it melts the surroundings.

It is traveling so fast that it has a very large kinetic energy even with small mass.

Planet __________ creates the gaps in the Asteroid belt called Kirkwood gaps. Mars Saturn Earth Jupiter

Jupiter

The gaps created by the planet Jupiter in the Asteroid belt are called _______. Kepler gaps Asteroid gaps Kirkwood gaps Jupiter gaps

Kirkwood gaps

Comets belong to the _________. Kuiper belt and Oort cloud Dwarf Planets and Asteroid belt Asteroid belt and Kuiper belt None of these choices are correct. Oort cloud and Dwarf Planets

Kuiper belt and Oort cloud

The short-period comets originate in _______ and the long-period comets originate in _______. Asteroid belt; Kuiper belt Kuiper belt; Oort cloud Kuiper belt; Asteroid belt Oort cloud; Kuiper belt

Kuiper belt; Oort cloud

Most Asteroids are found in the asteroid belt, which lies between the orbits of _________. Earth and Mars Saturn and Jupiter Mars and Jupiter Venus and Earth Neptune and Pluto

Mars and Jupiter

The main Asteroid belt lies between the orbits of _________. Pluto and the Oort cloud Earth and Mars Mars and Jupiter Saturn and Jupiter Venus and Earth

Mars and Jupiter

Which of the following is a characteristic that Pluto shares with the Jovian planets? It has a thick atmosphere. All of these choices are correct. None of these choices are correct. It is mostly composed of hydrogen and helium. It has a ring system.

None of these choices are correct.

What proves the existence of the Kuiper belt? Objects of the Kuiper belt were detected by the Hubble Space Telescope. the existence of short-period comets the fact that many comets orbit on the ecliptic the fact that comets are icy objects

Objects of the Kuiper belt were detected by the Hubble Space Telescope

How was the first asteroid discovered? Kepler traced back the path of meteors to the Asteroid belt. Galileo saw it whiz by Jupiter. Piazzi found it by searching for objects at the distance suggested by Bode's law. Newton inferred their existence by their gravitational influence on Jupiter. It collided with the Moon.

Piazzi found it by searching for objects at the distance suggested by Bode's law.

Which of the following is not an outer planet? Uranus Neptune Pluto Saturn Jupiter

Pluto

Which of the following are Dwarf Planets? Mercury and Eris Uranus and Neptune Neptune and Pluto Eris and Uranus Pluto and Eris

Pluto and Eris

Why do astronomers believe chondrite meteorites are about 4.6 billion years old—formed when the Solar system formed? There is no other reasonable time period in the solar system's history when any meteoroids could have formed. The chemicals they are made of were only common at the formation of the solar system. Their chemical composition suggests they are pieces broken off Mars, which is believed to have formed at that time. Radioactive dating can be used to determine their age.

Radioactive dating can be used to determine their age.

Why are there two tails to some comets? The "dust tail" is formed by solar radiation pressure. The "gas tail," is pushed out by the solar wind. Comets contain dense material which is attracted by the Sun's gravity, forming a tail which points toward the Sun. The "gas tail" is formed by solar radiation pressure. The "dust tail," is pushed out by the solar wind. The statement is false: comets have only one tail.

The "dust tail" is formed by solar radiation pressure. The "gas tail," is pushed out by the solar wind.

Astronomers believe that Pluto was pulled into the Solar System by Neptune. The hypothesis is supported by the fact that Pluto and Neptune have a 3:2 orbital period ratio. True False

True

Comets consist primarily of water, carbon dioxide, and carbon monoxide. True False

True

In the inner part of the Asteroid belt one is more likely to find silicate-rich asteroids, while the carbonrich asteroids are more abundant in the outer parts of the Asteroid belt. True False

True

The Oort cloud was probably formed by planetesimals that were tossed to the outer parts of the Solar System by the planets. True False

True

The coma around the nucleus of a comet can be 10 times the size of the Earth. True False

True

The combined mass of all of the asteroids is probably less than 1/1,000 the mass of the Earth. True False

True

can range in size from a few meters to many hundreds of kilometers

True

The radiant is the common point from which __________ seem(s) to diverge. asteroids meteorites a Meteor shower comets

a Meteor shower

What is the Kuiper Belt? a disklike swarm of icy objects that lies from near the orbit of Neptune to past Pluto's orbit a swarm of comet nuclei in a huge shell surrounding the Sun and planets a large belt containing asteroids in a gap between the orbits of Mars and Jupiter an enormous aggregate of gas and dust from which the Solar System was formed

a disklike swarm of icy objects that lies from near the orbit of Neptune to past Pluto's orbit

What is the Oort cloud? gas around a comet's head the gas boiled off a comet that forms its tail the glowing light around a meteor as it burns up a zone between the Sun and Mercury where comets burn up and release their gases a region in the outer Solar System from which comets come

a region in the outer Solar System from which comets come

What is a meteorite? any one of the large, rocky bodies that orbit the Sun, primarily between Jupiter and Saturn a glowing trail of hot gas and debris heated by friction as an object moves through the atmosphere a space rock that survives its fall through the Earth's atmosphere and reaches the ground the object that causes a "shooting star," but before it passes through the atmosphere

a space rock that survives its fall through the Earth's atmosphere and reaches the ground

All of the Asteroids in the Asteroid Belt together have a tiny fraction of the Earth's mass. about the Earth's mass. about ten times the Earth's mass. a mass somewhere between the mass of Mars and the mass of Jupiter.

a tiny fraction of the Earth's mass.

About how big is the largest asteroid known in the Solar System? about the size of the Earth about 50 feet about 50 miles about 50 yards about one-quarter the size of the Moon

about one-quarter the size of the Moon

Meteor showers are generally named after the Greek gods and goddesses. after the comet to which they belong. after the planet from which they seem to come to the Earth. after the constellation from which they appear to diverge.

after the constellation from which they appear to diverge.

The tail of a comet _________. trails behind the comet, pointing away from the Sun as the comet approaches it, and toward the Sun as the comet moves out of the inner Solar System points toward the Sun on its way into the Solar System, and away from the Sun on its way out always points toward the Sun always points away from the Sun

always points away from the Sun

In the process of fluorescence, __________ is absorbed by an atom and the energy is emitted as __________. an ultraviolet and one or more lower energy photons; a visible light photon an ultraviolet photon; at least one visible light and one or more lower energy photons a visible light and one or more lower energy photons; an ultraviolet photon a visible light photon; at least one ultraviolet and one or more lower energy photons

an ultraviolet photon; at least one visible light and one or more lower energy photons

Asteroids _________. are larger objects, a few hundred kilometers in size, but not quite large enough to be classified as a planet are small bodies, typically the size of a grain of sand or a boulder are about the same size as planets, but have not pulled themselves into a spherical shape can range in size from a few meters to many hundreds of kilometers

can range in size from a few meters to many hundreds of kilometers

Chondritic meteorites provide important clues because they are believed to be the source of all coal found on the Earth. contain many rare metals. be the only source of the necessary amino acids required for life. contain grains from the first material that condensed out of the Solar nebula.

contain grains from the first material that condensed out of the Solar nebula.

Comet nuclei typically have an average density of 0.5 g/cm3. This suggest a(n) _________ composition. icy and loosely packed gaseous icy and gaseous gaseous and rocky icy and rocky

icy and loosely packed

The existence of asteroids is supporting evidence of the solar nebula hypothesis, in that _________. the asteroids are probably fragments of a shattered planet inner belt asteroids are richer in silicate and iron materials and contain fewer carbon-rich materials asteroids in the inner Solar System are small and rocky, while those in the outer Solar System are larger and have atmospheres the gaps in the Asteroid belt are created by the same process that creates gaps in Saturn's rings

inner belt asteroids are richer in silicate and iron materials and contain fewer carbon-rich materials

A comet's tail _________. is gas and dust pulled off the comet by the Sun's gravity is gas and dust expelled from the comet's nucleus by the Sun's heat and radiation pressure always trails behind the comet is composed mainly of captured particles from the solar wind

is gas and dust expelled from the comet's nucleus by the Sun's heat and radiation pressure

The discovery of Charon was significant because it allowed astronomers to determine the ____ and ____ of Pluto. radius; speed speed; distance age; mass mass; radius distance; age

mass; radius

Fragments that do not completely burn in the atmosphere and eventually fall on the Earth are called meteors. meteoroids. asteroids. meteorites.

meteorites.

What are comets made of? mostly hydrogen and helium mostly iron, rock, and hydrogen None of these choices are correct. mostly oxygen and uranium mostly ice and frozen gases

mostly hydrogen and helium

A Dwarf Planet orbiting the Sun outside of Neptune's orbit is called a(n) _________. comet Oort Cloud Object neptoid plutino plutoid

plutoid

What is a typical asteroid made of? rock and iron liquid water solid carbon dioxide and other gases water frozen into ice solid hydrogen

rock and iron

Astronomers think that most comets come from _________. interstellar space material ejected by eruptions on the icy moons of the outer planets small icy bodies in the extreme outer parts of the Solar System that are disturbed into orbits that bring them closer to the Sun a region of space between the orbits of Mars and Jupiter

small icy bodies in the extreme outer parts of the Solar System that are disturbed into orbits that bring them closer to the Sun

Annual meteor showers such as the Perseids in August are caused by _________. passing asteroids triggering auroral displays nuclear reactions in the upper atmosphere triggered by meteoritic particle storms the Earth passing through the debris left behind by a comet as we cross its orbit the breakup of asteroids that hit our atmosphere at predictable times

the Earth passing through the debris left behind by a comet as we cross its orbit

The observation that there are asteroids made entirely of rock or entirely of iron suggests that _______________. large planetesimals formed entirely out of the same material the early Solar System had intermediate-sized differentiated planetesimals asteroids made of both rock and iron are particularly fragile and are easily destroyed these asteroids were formed from volcanic eruptions on early planets

the early Solar System had intermediate-sized differentiated planetesimals

What is the evidence for the existence of the Oort cloud? the fact that many comets orbit on the ecliptic the fact that some comets have retrograde orbits Objects of the Oort cloud were detected by the Hubble Space Telescope. the fact that new comets continue to appear indicates that a distant reservoir of icy bodies must exist

the fact that new comets continue to appear indicates that a distant reservoir of icy bodies must exist

Infrared observations are used to determine the mass of asteroids because ___________. the infrared radiation is the glow of heat from the asteroid, and larger asteroids emit more infrared light the Hubble Space Telescope only has infrared cameras most asteroids are made of dark minerals which are more efficient at reflecting infrared light than visible light asteroids reflect too little visible light to use optical telescopes for the measurements

the infrared radiation is the glow of heat from the asteroid, and larger asteroids emit more infrared light