ASTR Midterm 2

Which of the following does the Solar nebula (gas cloud) theory of the formation of the Solar system NOT predict?

 

Planets orbit the Sun in the same direction as the Sun's spin

 

Two fundamental types of planets (terrestrial and gas giants)

 

The equal number of terrestrial and jovian planets

 

Planets orbit around the Sun in nearly circular orbits in a flattened disk

 

The craters on the terrestrial planets

The equal number of terrestrial and jovian planets

The names of the planets in order of their distance from the Sun are

 

Venus, Mercury, Earth, Mars, Jupiter, Saturn, Uranus, Neptune

 

Mercury, Mars, Venus, Earth, Saturn, Jupiter, Neptune, Uranus

 

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune

 

Venus, Mercury, Earth, Mars, Jupiter, Saturn, Neptune, Uranus

 

Mercury, Venus, Earth, Jupiter, Mars, Neptune, Uranus, Saturn

 

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune

We can deduce the Solar System's age from

 

The ratio of radioactive materials in samples of old rocks

 

How long it takes light to cross the Solar System

 

We do not know the age of the Solar system

 

The ratio of hydrogen in the Earth's atmosphere compared with that in its crust

 

The amount of hydrogen in Earth's rocks

The ratio of radioactive materials in samples of old rocks

The competition between which two factors fundamentally determines whether a body has an atmosphere?

 

Surface gravity vs. UV radiation from the Sun

 

Size vs. UV radiation from the Sun

 

Size vs. rotation rate

 

Size vs. surface gravity

 

Rotation rate vs. UV radiation from the Sun

 

Size vs. UV radiation from the Sun

Which set of densities (in units of the density of water) are roughly representative for the planets?

 

Terrestrial = 3.5, gas giants = 3

 

Terrestrial = 5, gas giants = 1

 

Terrestrial = 1, gas giants = 5

 

Terrestrial = 10, gas giants = 1

 

Terrestrial = 5, gas giants = 0.1

 

Terrestrial = 5, gas giants = 1

Which planet shows evidence for sub-surface water ice?

 

Neptune

 

Venus

 

Mars

 

Jupiter

 

Mercury

Mars

The largest planet in the Solar system (by mass) is

 

Venus

 

Jupiter

 

Earth

 

Neptune

 

Mars

Jupiter

Which planet has the hottest surface and why?

 

Mercury, because it is closest to the Sun

 

Mars, because it has no magnetic field

 

Earth, because of global warming

 

Jupiter, because it is largest

 

Venus, because of the greenhouse effect

Venus, because of the greenhouse effect

What makes astronomers think that impact rates on the Moon must have been higher before 3.8 billion years ago?

 

All the large craters on the Moon come in pairs, while all recent craters are single

 

There are ten times more craters on the older highlands than the younger maria

 

Trick question, according to radioactive dating of Moon rocks, the Moon formed less than 3.8 billion years ago

 

The ancient sea basins on the Moon, whose water has since evaporated, show a lot more cratering

 

We see many more craters on the Moon that have been eroded by wind and rain

There are ten times more craters on the older highlands than the younger maria

Which of the following is NOT a way in which Jupiter differs from the terrestrial planets?

 

Its surface has more craters from early collisions

 

Its average density is lower

 

It includes more gas and liquid

 

It is larger in diameter

 

It is farther away from the Sun

 

Its surface has more craters from early collisions

We believe the maria on the Moon to be 

 

Flat, ancient plateaus on the Moon's highland areas

 

Ancient impact craters filled with lava

 

Oceans formed when the Moon had water

 

Large rifts filled with colder material made when the Moon's surface was cooling

 

Giant volcanoes formed when the Moon still had plate tectonics

Ancient impact craters filled with lava

Why would it be foolish to send astronauts to land on Jupiter?

 

It has no solid surface for them to land on

 

The great red spot is a strong source of radioactivity

 

Its clouds are so hot that any spacecraft getting near it would burn up

 

Its gravitational attraction is so weak that they would float off

 

Trick question, the idea is perfectly reasonable

It has no solid surface for them to land on

The composition of a planet like Jupiter resembles that of

 

The asteroids

 

The Moon

 

The Earth

 

Mars

 

The Sun

The Sun

The fact that Mars' axis of rotation is tilted similarly to that of Earth means that

 

It collided with a large meteorite that knocked it slightly on its side

 

It originated next to Earth and then slowly moved away

 

The length of its days are similar to Earth days

 

Its period of revolution around the Sun is the same as that of the Earth

 

It goes through similar seasonal changes

It goes through similar seasonal changes

The largest volcano on Mars is called

 

Mount Maxwell

 

Olympus Mons

 

Mariner Valley

 

Hellas

 

The Red Spot

Olympus Mons

Which of the following planets has the lowest average density?

 

Neptune

 

Jupiter

 

Earth

 

Saturn

 

Mercury

Saturn

One way in which Mars closely resembles Earth is

 

Its mass

 

The length of its day (period of rotation)

 

The make-up and thickness of its atmosphere

 

The length of its year (period of revolution)

 

Its surface gravity (i.e. what we would weigh there)

The length of its day (period of rotation)

We see a complex system of belts (or bands) in Jupiter's atmosphere because

 

The moon Io stirs up the atmosphere

 

The magnetic field is not centered on the planet's core

 

The chemical composition of the clouds varies systematically with latitude

 

Of stable wind patterns that vary with latitude

 

The band patterns are an optical illusion cause by our viewing angle

Of stable wind patterns that vary with latitude

One way to measure how long Jupiter takes to rotate is to watch the giant storms in its atmosphere go around. A more fundamental way to measure the rotation is to

 

Determine how long the innermost moons take to orbit Jupiter

 

Send a spacecraft like the Galileo probe into the top cloud layer

 

Determine the amount of methane in the planet's atmosphere

 

Measure the changes in the planet's radio waves, which are controlled by its magnetic field

Measure the changes in the planet's radio waves, which are controlled by its magnetic field

Both Neptune and Uranus appear blue in photographs because

 

Oxygen in the Earth's atmosphere scatters blue photons from distant planets

 

Trick question, Neptune and Uranus appear gray

 

Methane in their atmospheres absorbs red photons

 

Their high temperatures emit short wavelength blackbody radiation

 

We do not understand the origin of the blue color

Methane in their atmospheres absorbs red photons

The number of craters on the lunar highlands compared to those on the maria is evidence that the

 

Material composing the highlands is very soft and easily cratered

 

Maria are younger than the highlands

 

Maria are older than the highlands

 

Bodies that struck the Moon and made the craters were clumped in such a way that they missed hitting maria

 

Surface of the maria is liquid and craters quickly disappear there

Maria are younger than the highlands

The craters on Venus are relatively large because

 

Venus is so close to the Sun that the Sun pulls in all smaller objects before they hit Venus

 

Lakes on Venus quickly erode away the smaller craters

 

Mercury cleans out small objects from the inner Solar system (as evidenced by its many craters)

 

Venus is so hot that smaller craters quickly melt

 

Smaller objects break up in Venus' thick atmosphere before reaching the surface

Smaller objects break up in Venus' thick atmosphere before reaching the surface

Where has frozen water been discovered on the Moon?

 

In the maria (lava-filled regions)

 

Deep inside craters near the Moon's poles

 

In the highlands

 

At the bottom of most craters (at least on the Earth-facing side)

 

Trick question, no water has been found on the Moon yet

Deep inside craters near the Moon's poles

Which of the following is NOT a key reason why so many spacecraft have visited Venus and Mars?

 

Their atmospheres are very similar to Earth in composition

 

They have solid surfaces on which we can trace their geological history

 

Trick question, the majority of spacecraft have visited the Jovian planets

 

They resemble the Earth in a number of significant ways

 

They are the two planets closest to Earth

Their atmospheres are very similar to Earth in composition

As the Solar nebula (gas cloud) collapsed

 

It flattened out and became disk-shaped

 

The Sun was formed first and flung off bits and pieces that became the planets

 

Collisions between clumps of gas kept its rotation unchanged

 

Most of the mass stayed in the outer regions, not at the center

 

Hydrogen and helium were meanwhile converted into heavier elements that became the terrestrial planets

It flattened out and became disk-shaped

Why are the terrestrial planets so much smaller than the gas giants?

 

The gravity due to the Sun is stronger in the inner Solar system, which tidally compresses the terrestrial planets

 

Near the Sun, only hard-to-melt substances made it into planets, whereas the gas giants could accrete the more abundant hydrogen and helium

 

They spin so fast they flung off most of their original matter which has ended up in the comet cloud

 

They are formed from highly compressible material such as hydrogen and helium, so they could be squeezed into a smaller size by gravity

 

The Sun has pulled material off of them

Near the Sun, only hard-to-melt substances made it into planets, whereas the gas giants could accrete the more abundant hydrogen and helium

When a rock is held above the ground, we say it has some potential energy. When we let it go, it falls and we say that the potential energy is converted to kinetic energy. Finally, the rock hits the ground. What has happened to the energy?

 

It is converted into electromagnetic waves of all wavelengths

 

It is transformed back into the original amount of gravitational potential energy

 

It is lost on impact

 

It is stored inside the rock

 

It mostly goes into heating the ground, the rock, and the surrounding air

It mostly goes into heating the ground, the rock, and the surrounding air

Which of the following statements about Venus is true?

 

Its atmospheric pressure is about the same as Earth's

 

It rotates in the same direction as Earth

 

It is the largest terrestrial planet (by mass)

 

It has a thick layer of clouds containing sulfuric acid droplets

 

Its thick nitrogen-oxygen atmosphere acts like a greenhouse, keeping it hot

It has a thick layer of clouds containing sulfuric acid droplets

Volcanism is more likely on a planet that

 

Has high internal temperatures

 

Is closer to the Sun

 

Trick question, the occurrence of volcanism is simply random

 

Is struck often by meteors and solar system debris

 

Doesn't have at atmosphere or oceans

Has high internal temperatures

The planet that has the longest year (period of revolution) is

 

Jupiter

 

Saturn

 

Trick question, Kepler's laws say that all planets have the same period

 

Uranus

 

Neptune

Neptune

Jupiter, Saturn, Uranus, and Neptune are called "gas giants." In what sense is this term misleading?

 

They are not in any sense giants

 

The materials they are made of are not the kinds of thing we usually think of as gases, such as Oxygen or Nitrogen

 

There's nothing wrong with this term

 

They actually contain relatively little material in a gaseous state; much of their mass is liquid, metallic, or in strange high-pressure states

They actually contain relatively little material in a gaseous state; much of their mass is liquid, metallic, or in strange high-pressure states

The series of Soviet spacecraft that successfully landed on the surface of Venus were called

 

Magellan

 

Venera

 

Galileo

 

Pioneer

 

Voyager

Venera

What explains the long, branching channels on Mars that appear to have been created by flowing liquid, when we know of no liquids on the surface today?

 

They were actually formed by wind-blown dust during great dust storms

 

The water ice unfreezes in the summer

 

Mars had a thicker atmosphere and thus warmer temperatures in the past

 

They are actually created by plate tectonics

 

They were actually formed by volcanic lava from Olympus Mons

Mars had a thicker atmosphere and thus warmer temperatures in the past

This world is airless. Because of the lack of atmosphere, you must be careful not to look at the Sun so that you will not be blinded by the UV and X-ray radiation. However, you are able to determine that the Sun has the angular size you are used to on Earth. Where are you?

 

The Moon

 

Earth

 

Venus

 

Mercury

 

Mars

The Moon

Why does Mars appear reddish in color?

 

The red color is an optical illusion caused by the Earth's atmosphere scattering the colors of light differently

 

It is covered in clouds, which appear red due to methane

 

Mars is redshifted because it is (almost always) moving away from us

 

Mars' surface contains a lot of iron oxide (rust)

 

Giant volcanoes on Mars are constantly spewing out reddish lava

Mars' surface contains a lot of iron oxide (rust)

What is the source of the fine, powdery dust found on the Moon's surface?

 

Gas bubbling up from inside the Moon, which chemically changes the surface soil

 

Rivers and maria breaking up rocks, similar to sand on Earth

 

Volcanic activity over billions of years

 

We fundamentally do not know

 

Many impacts, breaking surface rocks apart over billions of years

Many impacts, breaking surface rocks apart over billions of years

We see a complex system of belts (or bands) in Jupiter's atmosphere because

 

The chemical composition of the clouds varies systematically with latitude

 

Of stable wind patterns that vary with latitude

 

The band patterns are an optical illusion cause by our viewing angle

 

The magnetic field is not centered on the planet's core

 

The moon Io stirs up the atmosphere

Of stable wind patterns that vary with latitude

Astronomers believe that Jupiter's strong magnetic field is caused by

 

A layer of metallic hydrogen inside Jupiter

 

Electric charges from the moon Io

 

A core of molten iron and nickel

 

Trick question, Jupiter does not have a strong magnetic field

 

The circulation of large reddish storms containing magnetic ammonia crystals

A layer of metallic hydrogen inside Jupiter

Which element can act like a metal when it is under tremendous pressure and is probably responsible for Jupiter and Saturn's magnetism?

 

Ammonia

 

Gold

 

Water

 

Helium

 

Hydrogen

Hydrogen

Which of the following is NOT a correct statement about the rotation of Venus?

 

The rotation rate of Venus had to be determined from radar measurements

 

A Venus day is 24 hours and 37 minutes, roughly the same as on Earth

 

Venus has the longest rotation period of any planet in the solar system

 

Venus rotates in a retrograde way (opposite to all other planets)

A Venus day is 24 hours and 37 minutes, roughly the same as on Earth

Short-period comets like Comet Halley

 

Return to the Oort Cloud during each of their orbits

 

Trick question, Halley is the only known short-period comet

 

Come back again and again at predictable intervals

 

Can never be observed without a telescope

 

Have a long tail visible during their entire orbit around the Sun

Come back again and again at predictable intervals

Which of the following statements about asteroids is true?

 

Asteroids are capable of having an orbiting moon

 

Asteroids have been known to do widespread damage to early civilizations

 

All other answers are correct

 

All asteroids, by definition, lie in the asteroid belt between Mars and Jupiter

 

According to estimates, asteroids appear to consist almost exclusively of solid rock

Asteroids are capable of having an orbiting moon

The tail of comet

 

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

 

Always points toward the Sun

 

Is gas and dust pulled off the comet by the Sun's gravity

 

Is made of redirected photons

 

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

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

Planets are spherical while most asteroids are irregularly shaped because

 

Gravity dominates over material strength in planets

 

Material strength dominates over gravity in planets

 

Gravity dominates over material strength in asteroids

 

Trick question, asteroids cannot be irregular in shape

Gravity dominates over material strength in planets

What is the best way to defend ourselves against an asteroid which is on course to collide with the Earth in, say, 10 years?

 

Use thermonuclear explosives to evaporate the asteroid entirely

 

Very slightly change the trajectory of the asteroid now using spacecraft or explosions

 

Move some people to the Moon so they could survive

 

There is no problem because all asteroid burn up by friction in the Earth's atmosphere

 

There is no possible protection

Very slightly change the trajectory of the asteroid now using spacecraft or explosions

Have any asteroids been found that are going to run into the Earth?

 

No asteroids have been predicted to hit the Earth since astronomers predicted the Chelyabinsk event in 2013

 

None of the asteroids that have been found so far are predicted to collide with the Earth within the timeframe of accurate predictions

 

We currently know of about 1000 asteroids on collision course

 

Astronomers aren't able to predict where asteroids will be in the future, so we do not know

 

A 1-kilometer asteroid is predicted to collide with the Earth in about 10 years, but it's so small that we don't have to worry about it

None of the asteroids that have been found so far are predicted to collide with the Earth within the timeframe of accurate predictions

When a chunk of cosmic material the size of a golf ball hits the Earth's atmosphere it makes a

 

Comet tail

 

Meteorite

 

Meteor shower

 

Asteroid

 

Meteor

Meteor

Many worlds in the solar system show extensive impact cratering, dating back billions of years. Which of the following worlds does NOT show such cratering?

 

Mars

 

Callisto

 

Mercury

 

Saturn

 

Our Moon

Saturn

Which of the following statements about comets is INCORRECT?

 

Long-period comets originate from a distant spherical source region called the Oort Cloud

 

Comets have a tail throughout their entire orbit around the Sun

 

Cometary gas tails usually point away from the Sun due to solar radiation pressure and the solar wind

 

Comets consist mostly of ice

 

Cometary dust left over from old comets give rise to meteor showers

Comets have a tail throughout their entire orbit around the Sun

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

 

Hydrogen

 

Vapor (gas)

 

Carbonaceous compounds

 

Ice

 

Metals

Ice

If everything in the solar system is moving around, why do the Perseid meteors repeat regularly around August 11th or so?

 

Because the Earth does not move relative to the debris pieces

 

Because the Earth's orbit intersects the same swarm of debris left behind by a comet at the same time each year

 

Because the Perseids are not in space at all, but in the upper layers of the Earth's atmosphere

 

Because August 11th is when the Sun's rays are the warmest, and thus tend to move the dust particles toward us at the fastest speed

Because the Earth's orbit intersects the same swarm of debris left behind by a comet at the same time each year

What features are abundant on Callisto and Ganymede but almost absent on Europa and Io?

 

Lakes of liquid ammonia

 

Rings

 

Markings that show the surface is made of ice

 

Volcanoes

 

Impact craters

Impact craters

Which of the Jovian planets does NOT have any satellites?

 

Uranus

 

Neptune

 

Saturn

 

Trick question, they all have moons

 

Jupiter

 

Trick question, they all have moons

Pluto's big satellite is called

 

Christy

 

Tombaugh

 

Charon

 

Titan

 

Ganymede

Charon

Which of the following is NOT evidence in support of the hypothesis that the Earth's Moon was formed during a giant impact?

 

The Moon formed slightly after the Earth (according to rock samples)

 

The Moon lacks volatile materials

 

The Moon's average density is roughly that of Earth's surface rock

 

The Moon has a very small core

 

The same side of the Moon always faces the Earth

The same side of the Moon always faces the Earth

When the Dawn spacecraft explored the largest asteroid Ceres, it discovered white spots that appear to be salt and volcanic mountains made of water ice. This led astronomers to think that

 

Ceres is one of the terrestrial planets that got kicked out of its former orbit

 

All asteroids are made of frozen water

 

Ceres may have (had) a liquid ocean under its crust

 

We might need a new category of "salty" asteroids

 

Ceres formed from the breakup of a much larger body, a solid planet bigger than Jupiter

Ceres may have (had) a liquid ocean under its crust

According to astronomical tradition, who gets to suggest the name for a newly discovered asteroid?

 

The discoverer of the asteroid

 

A task force within NASA

 

A special committee in Italy, where the first asteroid was discovered

 

The president of the country of the discoverer

 

A special committee of the U.N. set up for this purpose

The discoverer of the asteroid

In the far future, an entrepreneur with a large fleet of spaceships decides to capture and bring to Earth some valuable asteroids. If at that time, there is a shortage of usable metals on Earth, what type of asteroids should they search for?

 

S-type

 

Primitive

 

Trick question, asteroids are metal-free

 

M-type

 

C-type

M-type

Which of the following statements about the rocks brought back from the Earth's Moon by the astronauts is true?

 

Trick question, we never brought back rocks from the Moon

 

The Moon rocks are fundamentally different from Earth rocks, with materials never seen on Earth

 

The Moon rocks resemble rocks from the Earth's crust in many ways but also have subtle differences

 

The Moon rocks resemble Earth rocks in every detail

 

The Moon rocks did not survive long enough in the Earth's oxygen-rich atmosphere for us to analyze them

The Moon rocks resemble rocks from the Earth's crust in many ways but also have subtle differences

The fact that some asteroids cluster in what are called asteroid families is probably the result of

 

Random chance

 

Comets which pass through the asteroid belt and attract asteroids to them

 

Resonances with the Jovian planet orbits

 

Collisions which broke up larger bodies into a number of smaller ones

 

Strong magnetic fields found in some asteroids

Collisions which broke up larger bodies into a number of smaller ones

The bright streak of light we see as a meteoroid enters our atmosphere is caused by

 

Frictional heating as the meteoroid speeds through our atmosphere

 

Disturbances in the Earth's magnetic field

 

Disturbances in the atmosphere that refract light

 

Sunlight reflected from the solid body of the meteoroid

 

Radioactive decay of material in the meteoroid

 

Frictional heating as the meteoroid speeds through our atmosphere

Much of what we have learned about the gas giants and their satellites is due to two spacecraft called

 

Mariner

 

Voyager

 

Enterprise

 

Viking

 

Magellan

Voyager

The comet that broke into more than 20 pieces and collided with Jupiter in 1994 was

 

Halley's Comet

 

Hale-Bopp

 

Eros

 

Shoemaker-Levy 9

 

Churyumov-Gerasimenko (67P)

Shoemaker-Levy 9

The first asteroid to be discovered (and also the largest one) is called

 

Vesta

 

Gaspra

 

Eros

 

Davida

 

Ceres

Ceres

Halley's Comet was given that name because Edmond Halley was

 

The chief scientist who designed the probe that flew by the comet

 

The first to point out that the comet returns every 76 years or so

 

The prime minister of England at the time the comet was discovered

 

The first person to ever see that comet

 

The first person to be hurt by pieces falling off the come

The first to point out that the comet returns every 76 years or so

To become a star, a gas ball needs to have at least 8% of the mass of the Sun. This condition is imposed by

 

The temperature required to ignite fusion in the core

 

Sufficient pressure to withstand gravity

 

Sufficient rotation to withstand gravity (via angular momentum)

 

The ability to fuse deuterium to carbon

The temperature required to ignite fusion in the core

Astronomers are much more interested in the luminosity of a star than its apparent brightness because

 

Luminosity tells us an intrinsic characteristic of the star whereas brightness only tells us how it happens to look on Earth

 

Brightness can only be measured for binaries

 

Trick question, luminosity and brightness are two words for the same thing

 

Luminosity can be measured more exactly than brightness

 

Luminosity also tells us the elemental composition of the star

Luminosity tells us an intrinsic characteristic of the star whereas brightness only tells us how it happens to look on Earth

The stellar temperature changes not only the color but also the spectra of stars because

 

At too high temperatures, atoms tend to evaporate into gas and thus not absorb photons

 

Many elements are only formed in the photosphere of stars at the highest temperatures

 

Depending on temperature, certain atoms may be excited/ionized and thus (not) be available to absorb photons

 

At too low temperature, no atoms are excited and can thus not absorb photons

 

Trick question, the spectra do not vary with temperature

Depending on temperature, certain atoms may be excited/ionized and thus (not) be available to absorb photons

If the distance between us an a star is halved, with everything else remaining the same, the star's luminosity

 

Is increased by a factor of four, and the apparent brightness is increased by a factor of four

 

Remains the same, but the apparent brightness is increased by a factor of four

 

Is increased by a factor of two, and the apparent brightness is increased by a factor of two

 

Remains the same, but the apparent brightness is increased by a factor of two

Remains the same, but the apparent brightness is increased by a factor of four

What keeps the Sun from collapsing under its own gravity?

 

The fact that its interior is liquid and therefore can not be compressed

 

The forces generated by its extremely rapid rotation

 

The fact that its interior is mostly iron, giving it great strength

 

The outward force exerted by pressure of the gas in its hot interior

 

The intense magnetic fields in its core

The outward force exerted by pressure of the gas in its hot interior

What is the ultimate source of the energy emerging from the Sun?

 

Mass (a little of which is lost in each fusion reaction)

 

Chemical energy (from meteorites/asteroids that fall into the Sun and are vaporized)

 

Heavy nuclei (which are breaking apart into lighter nuclei)

 

Rotation energy (the Sun is spinning more and more slowly as it burns)

 

Potential energy (since the Sun is heated by gravitational contraction)

Mass (a little of which is lost in each fusion reaction)

The luminosity (energy output) of a star is determined by

 

Both its size and velocity

 

Its temperature

 

Its velocity

 

Both its size and temperature

 

Its size (radius)

Both its size and temperature

If stars A and B have the same luminosity but star B is three times farther away, then it will be (compared to star A)

 

Three times brighter

 

Same brightness

 

Nine times brighter

 

Three times fainter

 

Nine times fainter

Nine times fainter

You would show a friend an example of a cool star by pointing to one that is

 

Blue

 

Bright

 

Dim

 

Twinkling rapidly

 

Orange

Orange

For which type of star can astronomers measure the diameter with relative ease?

 

G-type stars

 

Eclipsing binary stars

 

Visual double stars

 

Brown dwarfs

 

Any star that is larger than a brown dwarf

Eclipsing binary stars

Why are high temperatures necessary for the nuclear reactions in stars?

 

Electrons must have enough speed to smash into each other, overcoming electrostatic repulsion

 

The nuclei must have enough speed to smash into the electrons

 

The electrons must have enough speed to smash into nuclei

 

The pressure in the core must be high enough to keep the nuclei apart

 

The nuclei must have enough speed to overcome the electrostatic repulsion

The nuclei must have enough speed to overcome the electrostatic repulsion

When one of the stars in a spectroscopic binary is moving toward the Earth, we observe that

 

The lines in its spectrum get brighter

 

It is no longer possible to learn what elements are in the star

 

The dips in the lightcurve get deeper

 

The lines in its spectrum merge with the lines of the other star

 

The lines in its spectrum show a blue-shift

 

The lines in its spectrum show a blue-shift

After energy is first produced by fusion deep in the core of the Sun, it moves outwards via

 

Convection (cells of hot material rising)

 

Radiation (photons executing a random walk between scatterings)

 

Sunquakes (waves analogous to Earthquakes)

 

Conduction (heat transfer through the Solar material)

 

Magnetic reconnection (field lines transporting energy)

Radiation (photons executing a random walk between scatterings)

What is an eclipsing binary star?

 

Two stars that orbit each other in a plane that happens to be aligned with our line of sight

 

A star twice as bright as the Sun

 

A binary star so close to the Sun that it is only visible during a Solar eclipse

 

A binary star where one of the members is a black hole

 

A binary in which certain spectral lines from the stars eclipse each other

Two stars that orbit each other in a plane that happens to be aligned with our line of sight

If star A is twice as massive as star B, roughly how much larger should we expect star A's luminosity to be?

 

2 times

 

4 times

 

16 times

 

32 times

 

8 times

 

16 times

From which part of the Sun do we receive most light?

 

Chromosphere

 

Core

 

Photosphere

 

Solar wind

 

Corona

Photosphere

Which of the following types of star has the lowest surface temperature?

 

A

 

G

 

F

 

M

 

O

M

Two stars that orbit each other are called

 

Paired stars

 

Brown dwarf pairs

 

Double stars

 

Binary stars

 

First contact stars

Binary stars

Do astronauts have to worry about space weather?

 

No, because modern spacesuits fully protect them from Solar wind particles

 

Yes, because coronal mass ejections (CMEs) happen daily

 

No, because the International Space Station's walls are made of protective lead

 

Yes, because a typical Solar flare could be lethal

 

Yes, because they are limited to a certain total amount of radiation during their career

Yes, because they are limited to a certain total amount of radiation during their career

Roughly when did scientists first use absorption lines in Solar spectra to identify elements in the Sun?

 

1900s (Annie Jump Cannon)

 

1860s (William and Margaret Huggins)

 

1930s (Cecilia Payne-Gaposchkin)

 

1620s (Galileo Galilei)

 

1820s (Joseph Fraunhofer)

 

1860s (William and Margaret Huggins)

What observable feature lets us measure the rotation rate of a star?

 

The position (wavelength) of (possibly shifted) atomic lines in its spectrum

 

The number of atomic lines in its spectrum

 

Shifts in the overall color away from the peak blackbody temperature

 

Increases in stellar radius due to angular momentum

 

The broadness of atomic lines in its spectrum

The broadness of atomic lines in its spectrum

The Sun's chromosphere and corona was discovered

 

By Galileo using his early telescopes

 

By eye, since it can be seen during total eclipses

 

In the late 19th century through the use of a spectrograph

 

By the Venera spacecraft on their way to Venus

 

By Annie Jump Cannon using early spectra

By eye, since it can be seen during total eclipses

When Solar wind particles follow magnetic field lines into the Earth's atmosphere, they cause

 

The reversing of the Earth's magnetic field

 

The greenhouse effect

 

The reddish color we see during sunsets

 

Aurorae (northern and southern lights)

 

Tropical storms (regions of rapidly rotating air)

Aurorae (northern and southern lights)

As you go outward from the Sun's photosphere

 

The layers get easier to see with the unaided eye

 

The composition changes drastically

 

The escaping light becomes increasingly redder

 

The temperature decreases

 

The density decreases

The density decreases

What do astronomers mean when they use the term "metals"?

 

Metallic hydrogen

 

Aluminum and all heavier elements

 

All elements heavier than Helium

 

Iron and all heavier elements

 

Radioactive metals (such as Uranium)

All elements heavier than Helium

Which of the following statements about forces is FALSE?

 

Forces change the momentum of a body

 

Forces always occur in equal and opposite pairs

 

Forces cause an acceleration to take place

 

For each attractive gravitational force, there is also a repulsive one

 

Where there is no force, objects continue to move the way they were moving

For each attractive gravitational force, there is also a repulsive one

 

Eclipses do not occur each month because

 

The Earth's rotation axis is tilted

 

Trick question, eclipses do occur each month, but they are generally visible only in very remote parts of the Earth

 

The Moon takes 6 months to complete its orbit around the Earth

 

The Moon's orbit is tilted with respect to the Earth's orbit around the Sun

 

The Moon's orbit is elliptical

 

The Moon's orbit is tilted with respect to the Earth's orbit around the Sun

By far the most abundant element in the Jovian planets is

 

Nitrogen

 

Hydrogen

 

Helium

 

Silicon

 

Oxygen

Hydrogen

The eventual loss of most of Mars's magnetic field, atmosphere, and liquid water was initiated by the

 

End of plate tectonics

 

Giant dust storm

 

Formation of Jupiter

 

Solidification of Mars's core

 

First eruption of Olympus Mons

Solidification of Mars's core

Astronomers estimate that there may be a trillion comet nuclei orbiting beyond Pluto, but we never see most of them because they

 

Remain in stable orbits beyond Pluto

 

Are so small that they pass by the Earth completely undetected

 

Collide with Jupiter before making it to the inner Solar system

 

Are not made of ice and thus have no tails

 

Have orbits that only bring them inward as far as the orbit of Jupiter

 

Remain in stable orbits beyond Pluto

Which of the following planets does not have any moons?

 

Mars

 

Jupiter

 

Trick question, all of them have moons

 

Earth

 

Venus

Venus

The majority of the moons orbiting the Jovian planets are

 

Dirty snowballs

 

Large moons, roughly the size of Pluto or Mercury

 

Small moons orbiting in the same direction that their planet orbits

 

Much warmer than the planet they orbit

 

Small moons orbiting in retrograde direction (opposite to the direction their planet orbits)

 

Small moons orbiting in retrograde direction (opposite to the direction their planet orbits)

The tail of comet

 

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

 

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

 

Always points toward the Sun

 

Is gas and dust pulled off the comet by the Sun's gravity

 

Is made of redirected photons

Is gas and dust pulled off the comet by the Sun's gravity

What does E = mc^2 really mean?

 

Matter can only yield energy if particles are colliding

 

Matter can be changed into energy and vice versa (with an "exchange rate" of c^2)

 

Light is slowed down by its energy

 

Energy travels at the speed of light squared while matter must travel more slowly

 

Matter has to travel at the speed of light before it can produce energy

Matter can be changed into energy and vice versa (with an "exchange rate" of c^2)

The Sun is powered by the conversion of

 

Helium into carbon

 

Hydrogen into helium

 

Hydrogen and oxygen into water

 

Gravity into energy

 

Light into potential energy

Hydrogen into helium