4

What is the typical distance between asteroids in the asteroid belt?

10 million km

In 2013, a small stony asteroid collided with the Earth above the Russian city of Chelyabinsk. What was the result?

A fireball briefly brighter than the Sun could be seen in the sky

What is the largest known asteroid in our solar system?

Ceres

What is the one observation of Triton, the giant moon of Neptune, that seems to indicate that it was captured by the gravity of the planet rather than being formed as part of the Neptune system?

It orbits in a retrograde direction, opposite to the planet's rotation.

A Canadian college student who has taken an astronomy class goes home for the holidays and persuades his parents to let him borrow the family car. When he returns, he finds that his parents are very angry with him, claiming he left the garage door open. Yet he remembers that he carefully closed the garage door with the electronic remote control in the car. After consulting with his astronomy instructor, he comes up with an alternative explanation for why the garage door is open. Which of the following is PART of that explanation?

It was a time of solar maximum, and there had been a big flare on the Sun earlier

How does the magnetosphere of Jupiter compare to that of the Earth?

Jupiter's magnetosphere is much larger than that of the Earth because of Jupiter's large magnetic field and the weakness of the solar wind at Jupiter's orbital distance from the Sun.

The asteroid belt exists between the orbits of the planets

Mars and Jupiter.

Which of the following statements about NEO's (Near Earth Objects) is TRUE?

NEO's can include both asteroids and comets that cross the Earth's orbit

Around which object does Titan orbit?

Saturn

Which planet has wide, bright rings that are easily visible from the Earth?

Saturn

Which of the following best describes the first set of experiments, using chlorine traps, that were searching for electron neutrinos from the Sun?

The chlorine experiments found only between 1/3 the number of electron neutrinos arriving from the Sun that our models predicted should be coming

Astronomers have concluded that the Sun's activity varies in an 11-year cycle. Which of the following statements about this cycle is TRUE:

The number of sunspots gets larger and smaller over the course of 11 years

Saturn is less massive than Jupiter but almost the same size. Explain.

The smaller mass exerts less gravitational force and is unable to compress the mass as much as in Jupiter.

How can astronomers measure the age of a meteorite that fell from the skies?

They measure the amount still left of radioactive materials in the meteorite, and how much has turned into decay products

Miranda is a satellite of

Uranus

The rotation axis of which planet is tilted at 98° from the vertical to its orbit?

Uranus

Jupiter and Saturn are mostly liquid hydrogen. How (if at all) do the interiors of Uranus and Neptune differ from this?

Uranus and Neptune have a much thicker layer of water outside the rocky core, as well as a much thinner mantle of liquid hydrogen mantle.

Which of these worlds is the most active geologically?

Venus

Which of the following statements about the tails of comets is FALSE?

a comet always has a nice long tail, even when it is far from the Sun

The Kuiper belt is

a flat or donut-shaped distribution of distant comets around the Sun, extending out about 500 AU.

Who pays the bill for the energy generated by nuclear fusion in the Sun? In other words, where does the energy pouring out of the Sun come from ultimately?

a little bit of mass is lost in each fusion reaction and is turned into energy (the Sun is losing mass)

Jupiter's satellite Europa is believed to be made up of

a metallic core and a rocky mantle covered with a liquid water ocean whose surface is frozen.

Which of the following particles has the lowest mass?

a neutrino

An asteroid is

a planetesimal moving in an orbit around the Sun.

Europa, one of the Galilean satellites of Jupiter, has a surface consisting of

a relatively young, icy crust covered with a network of streaks and cracks and only a few impact craters.

The Oort cloud is

a spherical distribution of distant comets around the Sun, extending out about 50,000 AU.

If there are at least a million asteroids, how did spacecraft like Galileo survive their trip through the asteroid belt?

although there are many asteroids, they are widely spaced (there is lots of space between them)

The first technique that allowed astronomers to find exoplanets involved:

answer marked as correct: looking for the decrease of light from the star during a transit of the planet across its disk actual correct answer from the book: measuring changes in the radial velocity (Doppler shift) of the star caused by the pull of orbiting planets

A chunk of rock and metal 10 km in diameter orbiting the Sun would be called a(n)

asteroid

The Kirkwood gaps (see Figure 7-11, Comins, Discovering the Essential Universe, 5th ed.) are in the

asteroid belt at places where there are very few asteroids.

Which of the following statements about the violent events on the Sun called flares is FALSE?

astronomers think that flares are connected with sudden changes in the magnetic field of the Sun

Solar wind particles can be captured by the Earth's magnetosphere. When these particles spiral down along the magnetic field into the atmosphere, they are responsible for:

aurorae (northern and southern lights)

In a single photograph of a comet and its tail, the only direction that one can determine with certainty is the direction

away from the Sun because the tail is pushed in this direction by the solar wind.

A comet's tail always points from the comet head

away from the Sun.

The dark, reddish bands on Jupiter are called

belts

How was Neptune discovered?

by a careful application of Newton's laws to the somewhat irregular motions of Uranus

Astronomers first detected the presence of a wind of particles coming from the Sun by

by noting the wind's effects on the tails of comets

The hotter region directly above the Sun's visible surface is called the

chromosphere

Short-period comets like Comet Halley

come back again and again at predictable intervals

The hottest zone in the Sun is the

core

In the Sun, when a positron and an electron collide, they will produce:

energy in the form of a gamma ray

The rings of Uranus were

first discovered while observing the occultation of a star by the Uranian system.

When a periodic comet leaves its dusty debris behind in its orbit, the Earth can intercept this debris and

have a meteor shower as the dust burns up

The most common element in the Sun is

hydrogen

The planet Jupiter consists mostly of

hydrogen

A main difference between asteroids and comets is that asteroids are mostly made of rock and comets are mostly made of

ice

Dark spokes that are visible in Saturn's rings are believed to be caused by

interaction of dust in the rings with Saturn's magnetosphere.

As a result of measurements by the Galileo spacecraft, what is now believed to be the internal structure of Io?

iron core overlaid by a molten mantle and rocky crust

There is strong evidence that Saturn's largest satellite, Titan, has

lakes and rivers of liquid methane and ethane.

What features dominate the surface of Callisto, one of Jupiter's satellites?

large craters, densely spread over the entire surface

In addition to hundreds of smaller objects they have been discovering in the Kuiper Belt recently, astronomers were surprised to find

larger bodies, with sizes as big as Pluto (now called dwarf planets)

In what form is the hydrogen in the interior of Jupiter?

liquid metallic hydrogen, electrically conducting

Which of the following is NOT an experiment that is searching for neutrinos coming from the Sun?

looking for changes in the Doppler shift of lines in the atmosphere of the Sun

A small particle of rock orbiting the Sun would be called a

meteoroid.

Astronomers estimate that about 25 million meteors strike the Earth's atmosphere each day. How come we haven't run out of meteors in the long history of the Earth?

meteors are pieces of dirt left over from the formation of our solar system and from old comets; there is a huge supply of small dirt particles from both sources

The whitish clouds that are visible in photographs of Neptune consist of

methane ice crystals.

Three kinds of worlds are round in our solar system. Which of the following is NOT a type of world that is typically round?

minor planet (asteroid)

Comets get significantly brighter in our skies as they approach the Sun because

more than one of the above: -they reflect more sunlight as they get closer to the source of light -they get closer to the Earth than when they were outside the orbit of Mars -they move faster and faster

If you were standing on Pluto, how often would you see the satellite Charon rise above the horizon each day?

never—Charon is a synchronous satellite with an orbital period exactly equal to Pluto's rotation period

When a large nucleus breaks apart (or is broken apart) into two smaller pieces, this is called

nuclear fission

Stony iron meteorites are believed to

originate from differentiated asteroids (in which iron sank to the center).

Most comet nuclei are believed to be

pieces of dusty ice left over from the formation of the solar system.

When the solar system was forming, the building blocks from which the protoplanets gathered together were the:

planetesimals (a few km to tens of km wide)

Which of the following is NOT one of the fundamental particles that we find inside atoms?

positrons

When energy is first produced by fusion deep in the core of the star, that energy moves outward mostly by what process?

radiation

One way to find a new meteorite is to:

search the area beneath or close to the point where a bright fireball was seen to burn out

"Markings" on the surface of Saturn are

similar in appearance to those on Jupiter but much less distinct.

A shooting star is a

small particle of interplanetary dust burning up and glowing as it enters the Earth's atmosphere.

In order of abundance, from most abundant to least abundant, the occurrence of meteorite impacts ("falls") is believed to be

stony, iron, stony iron

Jupiter's Great Red Spot is probably a(n)

storm

The major chemical constituent of the layers of material continuously being deposited on the surface of Io, the innermost moon of Jupiter, by "volcanic" action is

sulfur

The "snow" that falls continuously on the surface of Io, the innermost Galilean moon of Jupiter, is composed of

sulfur and sulfur dioxide.

Which of the following is not a characteristic that worlds in our solar system have in common:

that all the planets have solid surfaces on which we can see impact craters

A meteor shower results from

the Earth passing through debris of an old comet.

What mechanisms do astronomers believe is responsible for making the Sun's outer atmosphere so much hotter than its photosphere?

the Sun's magnetic field interacting with the charged particles that make up the atmosphere

How do astronomers know how strong the magnetic field of the Sun is?

the measure the Zeeman effect (the splitting of spectral lines)

A college friend of yours who has been postponing taking any science courses hears you talking about the generation of nuclear energy in the Sun and makes the following observation: "The whole idea of the atomic nucleus is pretty ridiculous. If an oxygen nucleus consists of eight protons and eight neutrons, the charge on that nucleus is positive. Since even I learned in high school that like charges repel, such a nucleus would find all its positive protons repelling and quickly fall apart." How would you answer his argument?

the nuclear force, which is attractive over short distances like the nucleus, and stronger than electricity, holds the nucleus together

Which part of a comet is the DENSEST?

the nucleus

If it takes an average of 14 billion years before any proton inside the Sun will undergo fusion, and the Sun is only about 5 billion years old, why do astronomers believe that fusion is going on there now?

there are an enormous number of protons inside the Sun, and some of them will fuse much sooner than the average

When larger fragments of Comet Shoemaker-Levy 9 crashed into Jupiter in 1994,

they exploded in Jupiter's atmosphere, releasing energy equal to millions of megatons of TNT

Does Jupiter have rings orbiting the planet?

yes, three very thin rings composed of fine dust particles

Which of the following planets does NOT have an atmosphere?

you can't fool me: all of the above (Earth, Venus, Jupiter, Neptune) have an atmosphere