question

Around which planet does the satellite Titan orbit?

answer

Saturn

question

How was Neptune discovered?

answer

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

question

Jupiter has a magnetic field that is

answer

much more powerful than that of Earth.

question

Neptune's high cirrus clouds consist of

answer

methane ice crystals.

question

On which planet can we see prominent but variable ice caps?

answer

Mars

question

On which planetary body can distinct evidence be seen for the flow of water at an earlier time?

answer

Mars.

question

Phobos and Deimos are moons of which planet?

answer

Mars.

question

The Martian magnetic field is

answer

weak and localized, not at all like the global magnetic field of Earth.

question

The four giant moons of Jupiter were discovered by

answer

Galileo

question

The geology and geography of the surface of the Venus is best described as

answer

mostly volcanic plains, with two continent-sized uplands, and a number of large volcanoes.

question

The highest daytime temperature reached on the surface of Mercury is

answer

430°C, high enough to melt lead and tin.

question

The reddish color of Mars is probably due to

answer

iron oxides such as rust.

question

Tomorrow's weather report for Venus would be

answer

overcast and very hot.

question

Triton is a satellite of

answer

Neptune

question

Venus

answer

has no magnetic field

question

What characteristic features are seen on the visible surface of Jupiter?

answer

Light bands of cloud separated by dark regions parallel to the equator

question

What is the Great Red Spot?

answer

A large and long-lived, possibly permanent, storm on Jupiter.

question

What is the composition of Saturn's rings?

answer

Water ice or ice-coated rock

question

Where has water ice been found on Mercury?

answer

In permanently shadowed crater floors at the north and south poles.

question

Which is the hottest planet in the solar system, measured at the surface?

answer

Venus.

question

Which is the only planet whose surface features can easily be seen through a telescope from Earth?

answer

Mars

question

Which of the following features have NOT been seen or detected on Mars?

answer

Active volcanoes.

question

Which of the following planets has no moon?

answer

Venus

question

Which of the following properties do the terrestrial planets, Mercury, Venus, Earth and Mars, have in common?

answer

They all have solid surfaces.

question

Which of the planets fits the following description: "A planet with solid, cratered surface which is alternately very hot and very cold, and having no atmosphere"?

answer

Mercury

question

A comet's tail

answer

8-1

question

A ______is a comet that passes extremely close to the Sun at perihelion sometimes within a few thousand kilometers of the Sun's surface.

answer

sun grazing comet

question

A meteoroid is the name used to describe a solid particle that

answer

is drifting around in space.

question

A piece of rock from outer space that reaches the Earth's surface after surviving a fiery passage through the Earth's atmosphere is known as a(n)

answer

meteorite.

question

A shooting star is

answer

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

question

An asteroid is

answer

a planetesimal moving in an orbit around the Sun.

question

Asteroids trapped in one of the Lagrangian points of Jupiter are called Apollo-Amor objects.

answer

False

question

Asteroids which orbit the Sun at the same distance as Jupiter are known as

answer

Trojans

question

Asteroids whose orbits carry them across the Earth's orbit are known as

answer

Apollo asteroids

question

Comet tails are the result of

answer

melting and evaporation of ices from the comet core.

question

Jupiter was probably influential in preventing the formation of a planet at the present location of the asteroid belt.

answer

True

question

The Kirkwood gaps are caused by

answer

the gravitational pull of Jupiter, which nudges asteroids into new orbits.

question

The asteroid belt exists between the orbits of the planets

answer

Mars and Jupiter

question

The asteroid belt is believed by most astronomers to be composed of

answer

8-14

question

The cause of the "meteor showers," seen at regular times each year upon Earth, is most probably

answer

the Earth moving through the remnant dust and rock fragments of an old comet which are orbiting the Sun in the comet's old orbit.

question

The first great comet of the 21st century was Comet

answer

Comet McNaught

question

The ionized gas tail of a comet is always aligned

answer

in the comet-Sun line.

question

The most common meteorites to hit the Earth are

answer

the stony meteorites

question

The nucleus of a typical comet is

answer

irregular in shape, with a very dark and cratered surface.

question

The number of times that a typical comet can pass close to the Sun (i.e., the number of orbits that the comet can complete) before it is completely vaporized or destroyed is about

answer

100

question

The orbits of comets are

answer

randomly oriented in the solar system and can extend far beyond the orbit of Pluto.

question

The particular feature of a comet that exhibits the most structure and always points away from the Sun is

answer

]its ion or gas tail.

question

The tail of a comet always points toward the sun.

answer

False

question

____________ is the only dwarf planet located in the main asteroid belt.

answer

Ceres

question

_______________ is the largest dwarf planet by mass.

answer

Eris

question

Energy is transported from the center of the Sun to the surface by

answer

mostly radiation; convection only in the outer layers.

question

How does the Sun's overall magnetic field behave?

answer

The northern and southern hemispheres have opposite magnetic polarity, and this polarity reverses every 11 years.

question

Sunspots are areas on the sun that are

answer

cooler than their surroundings.

question

Sunspots are caused by

answer

differential rotation and its effect on weak magnetic fields just under the solar surface.

question

The Sun's energy is generated by

answer

nuclear fusion

question

The _________________________ is then given by the sum of the number of individual sunspots and ten times the number of groups.

answer

sunspot number

question

The brighter cells surrounded by dark, narrow boundaries making up the cellular pattern that completely covers the visible surface of the Sun are called

answer

granules.

question

The gas motions within granules on the solar surface are

answer

upward flow in the bright cell centers and downward flow around the darker edges.

question

The rotation of the Sun is

answer

fastest at the equator, slower at mid-latitudes, and slowest near the poles.

question

The temperature of the Sun's photosphere is

answer

5800 K.

question

The two forces producing hydrostatic equilibrium in the sun are

answer

nuclear forces and gravity.

question

What are the names of the three layers in the Sun's atmosphere, in order from highest to lowest?

answer

Corona, chromosphere, photosphere.

question

What is a spicule on the Sun?

answer

A jet of rising gas in the chromosphere.

question

What is the average length of time from one maximum in the number of sunspots on the Sun to the next maximum?

answer

11 years

question

What is the character of the sunspot cycle?

answer

Starting at sunspot minimum, spots first appear far from the equator, followed by new spots appearing closer to the equator as they increase in number, then die out close to the equator.

question

What is the name of a sudden eruptive surge on the surface of the Sun?

answer

A flare

question

What is the name of the layer of the Sun's atmosphere that appears as a pinkish ring just outside the visible disk of the Sun during a total solar eclipse?

answer

The chromosphere.

question

What is the photosphere of the Sun?

answer

The visible "surface" of the Sun.

question

What is the reason why the edge of the Sun's visible disk is darker than the center?

answer

9-19

question

What is the solar wind?

answer

The Sun's outer atmosphere streaming out into space.

question

What process provides the power for the Sun?

answer

The fusion of hydrogen into helium.

question

Where is the chromosphere on the Sun?

answer

It is the layer above the visible surface of the Sun.

question

Where is the coolest region in the Sun?

answer

In the photosphere.

question

__________________ are regions of higher temperature and density surrounding sunspots.

answer

Plagues

question

The _____________ is the Sun's outer atmosphere. It is visible during total eclipses of the Sun as a pearly white crown surrounding the Sun.

answer

Corona

question

A star in the lower left part of the Hertzsprung-Russell diagram, compared to a star in the middle of the diagram, is

answer

smaller

question

Absorption line strengths are used in the spectral classification of stars and the determination of surface temperatures. Which of the following atomic or molecular constituents will exhibit strong absorption lines in spectra from stars with very high surface temperature?

answer

10-2

question

An astronomer is measuring the brightness of a particular star through a telescope, using different filters in the visual (yellow-green), violet, and ultraviolet regions. What is the name of the technique being used by this astronomer?

answer

Photometry

question

An object which is too massive to be a planet but not massive enough to be a star is called

answer

A brown dwarf

question

At what stage of its evolutionary life is the Sun?

answer

Main sequence, middle age.

question

If a star is 100 light years away, what is its approximate distance in parsecs?

answer

30 parsec

question

If the surface temperature of a star is very low, which of the following atomic or molecular constituents will produce the most prominent absorption lines in its spectrum?

answer

TiO

question

Spectral types of stars (e.g., O, B, A, F, G, K, M) define uniquely their

answer

surface temperatures.

question

Suppose you observe a previously undiscovered star and find its apparent magnitude. To determine its absolute magnitude you need to know the stars

answer

distance

question

The Hertzsprung-Russell diagram is a plot of

answer

absolute magnitude (or intrinsic brightness) against temperature of a group of stars.

question

The Sun's classification in terms of its surface temperature, as determined from absorption lines in its spectrum, is

answer

G2

question

The absolute magnitude of a star is

answer

equal to the apparent magnitude if the star is 10 parsecs away.

question

The chemical makeup of the Sun's surface can be determined

answer

by solar spectroscopy.

question

The most likely places where stars and planetary systems are forming in the universe are

answer

in nebulae composed of gas and dust.

question

The spectral class of the star Enif is K2, while that of the Sun is G2. Which of the following conclusions can be drawn about Enif from this information?

answer

It is cooler than the Sun.

question

The surface temperature of a nearby star can best be determined from spectral classification by examining

answer

the pattern of spectral absorption lines from various atoms.

question

What is a protostar?

answer

A small interstellar cloud, before it collapses to become a star.

question

What is a red giant?

answer

A star that is burning hydrogen into helium in a shell around the core.

question

What is a white dwarf star?

answer

A star of about the same size (diameter) as the Earth.

question

What is the most abundant element in the universe?

answer

Hydrogen

question

When observed through a set of photometric filters, the brightness of a distant star is seen to be brightest through the ultraviolet filter, less bright through the blue filter, and faintest through the yellow filter. What conclusion can be drawn from this information, assuming no absorption of light between the star and Earth?

answer

The star has a very high surface temperature.

question

Where are the most massive stars to be found in the main sequence of a Hertzsprung-Russell diagram?

answer

The upper, left end.

question

Where on the Hertzsprung-Russell diagram do most local stars in our Universe congregate?

answer

On the main sequence, where stars are generating energy by fusion reactions.

question

Which important stellar parameter can be best determined by observations of binary stars?

answer

Steller Mass

question

Which of the following four spectral classifications represents the coolest stellar surface temperature?

answer

G4

question

A particular giant molecular cloud in interstellar space has a mass of 2,000,000 solar masses. What is the mass of helium in this cloud?

answer

500,000 solar masses.

question

After hydrogen burning ends in a star's core, its position on the Hertzsprung-Russell diagram moves in a direction toward the

answer

upper right

question

At what point in its evolution will a protostar stop shrinking and stabilize into a star?

answer

When nuclear processes generate enough energy and internal pressure to resist gravitational contraction.

question

For any star on the main sequence, the same star when it was a protostar was

answer

larger and cooler

question

How does the temperature of an interstellar cloud affect its ability to form stars?

answer

Higher temperatures inhibit star formation.

question

Hydrogen in molecular form, H2, is thought to be very abundant in gas clouds in space, but these molecules emit radiation relatively inefficiently, since they are symmetrical molecules. Which other molecule occurs in close association with H2 and is used as a probe for molecular clouds?

answer

CO

question

In which part of the electromagnetic spectrum are molecules most easily detected?

answer

Radio waves

question

New stars are formed from

answer

huge, cool dust and gas clouds

question

Objects that are intermediate between stars and planets.

answer

Brown dwarf

question

Process of combining nuclei.

answer

11-10

question

Star formation takes place in

answer

giant molecular clouds

question

The Jeans instability describes

answer

the overcoming of gas pressure by self-gravity within a cold and dense interstellar cloud to form a star.

question

The __________________ is the "mountain" in the potential energy that must be crossed over to move the two nuclei close enough together to fuse.

answer

Coulomb barrier

question

The energy released in a thermonuclear reaction comes from the conversion of matter into energy according to ____________ equation.

answer

Einstein's

question

The evolutionary tracks of stars during the formation process.

answer

Hayashi Tracks

question

The lowest mass that a protostar can have and still become a star (i.e., start thermonuclear reactions in its core) is

answer

slightly less than 1/10 of a solar mass.

question

The major part of a star's life is spent on the:

answer

Main Sequence

question

The space between stars is known to contain

answer

gas, both atomic and molecular, and dust.

question

What do our atmosphere and a reflection nebula surrounding a star have in common?

answer

They both appear blue because of preferred scattering of this color of light.

question

What fraction of the mass of a typical interstellar cloud is hydrogen?

answer

74%

question

What is believed to be the maximum mass that a star can have?

answer

About 100 solar masses.

question

________________ is the process of splitting atoms and powers atomic bombs and nuclear power reactors.

answer

Fission

question

While a star is on the main sequence, its energy comes primarily from

answer

nuclear fusion

question

Which are the two most abundant elements in the universe?

answer

Hydrogen and Hellium

question

What is the relationship between the mass of a protostar and the time needed for it to reach the main sequence, after it forms inside an interstellar cloud?

answer

More massive protostars reach the main sequence in a shorter time than less massive protostars.

question

A Type II supernova is

answer

the explosion of a massive star after silicon burning has produced a core of iron nuclei.

question

A black hole can be thought of as

answer

strongly curved space

question

A planetary nebula is

answer

an expanding gas shell surrounding a hot white dwarf star.

question

A white dwarf is

answer

a small, very hot, low-mass star.

question

A white dwarf star is about the same size as

answer

the Earth

question

Black holes are so named because

answer

no light or any other electromagnetic radiation can escape from inside them.

question

During which phase of a low-mass star's life does helium shell burning occur?

answer

Asymptotic giant branch

question

Helium nuclear reactions (helium burning) produces primarily

answer

carbon and oxygen

question

Our Sun will end its life by becoming

answer

A white dwarf

question

The endpoint for the evolution of a low mass star is

answer

white dwarf

question

The final remnant of the evolution of a red giant star that has ejected a planetary nebula is

answer

a white dwarf star

question

The length of a star's main sequence life is determined by the stars:

answer

spectral type

question

The main product of silicon fusion reactions in the core of a massive star is

answer

iron

question

The stars which eventually become white dwarfs are those which start life with masses less than

answer

8 solar masses

question

The words "Schwarzschild radius" refer to

answer

the distance from the center of a black hole to the point at which the escape velocity becomes equal to the speed of light.

question

What is the escape velocity from inside a black hole?

answer

Greater than the speed of light.

question

What is the event horizon of a black hole?

answer

The "surface" from inside of which nothing can escape.

question

What name is given to a non-rotating black hole?

answer

A Schwarzschild black hole.

question

What name is given to a rotating black hole?

answer

A Kerr black hole.

question

Which force induces the core to condense and collapse in massive stars at the conclusion of each episode of nuclear fusion, such as the carbon, oxygen and silicon fusion cycles?

answer

Gravity.

question

Which nuclear fusion cycle follows the helium fusion phase as a massive star evolves?

answer

Carbon "burning".

question

Which of the following objects is NOT an end-point of a star's evolutionary life?

answer

Red Giant

question

Which of the following stars is most dense?

answer

White Dwarf

question

Which of the following statements is NOT a property of neutron stars?

answer

They contain strong gravitational fields but weak magnetic fields.

question

Which of the following will a high-mass star (say, 25 times the mass of the Sun) NOT do at or near the end of its life?

answer

Eject its outer layers and become a white dwarf

question

A particular galaxy has a nuclear region of more or less uniform brightness from which long lanes of stars curve outward. What type of galaxy is this?

answer

Spiral

question

An astronomer studying a distant cluster of galaxies finds that several of the galaxies are spiral-shaped, with a large nuclear region and tightly wound arms. How should the astronomer classify these galaxies?

answer

Sa

question

Astronomy with a radio telescope was initiated by

answer

an amateur astronomer Grote Reber, after Jansky had detected radio energy from the galaxy.

question

Double radio sources, quasars, and BL Lacertae objects are now considered to be the same basic type of object—an accretion disk producing two oppositely directed jets—but appear to us to be very different because

answer

we view them at different angles to the line of the double jets. Face-on to the accretion disk the source will look like a BL Lac object, edge-on as double radio sources, and between these positions a quasar

question

Faint star like objects producing intense radio energy that eventually were called quasars were found to have an unusual feature in their optical spectra. This feature was

answer

an extreme redshift of emission lines that indicated high recessional velocities and hence great distances, requiring extremely high energy output in order to be detected

question

In the "unified model" of active galaxies, the main difference between quasars, BL Lacertae objects, and radio galaxies appears to be that

answer

we see the accretion disk around the central black hole from a different angle in each case—face-on for BL Lacertae, edge-on for radio galaxies, and in between for quasars

question

In the verification of the Hubble law for the expansion of the universe and the determination of the constant H0, the greatest difficulty has been

answer

the accurate determination of distances to very distant galaxies.

question

One of the first three astronomical objects detected at radio wavelengths by Grote Reber in the late 1930s was

answer

the galactic center

question

Quasars appear to be

answer

very distant and intrinsically bright objects moving in random directions at high speeds.

question

Seyfert galaxies are

answer

spiral galaxies with extremely active cores

question

The Hubble law, representing observations of distant objects in the universe, relates which two parameters?

answer

The mass of a distant object and its recession velocity.

question

The Milky Way Galaxy appears to have a spiral structure with

answer

four separate major arms.

question

The distance to the bright quasar, 3C 273, is estimated to be

answer

2 billion light years

question

The factor that misled Herschel into concluding that the stars of the Milky Way were distributed with the Sun at the center of the Galaxy was

answer

interstellar dust, which obscured the more distant stars and thereby localized his observations.

question

What is a barred spiral galaxy?

answer

A galaxy with a bar through the nuclear bulge and the spiral arms starting from the ends of the bar

question

What is an Einstein ring?

answer

An example of the image formed by a gravitational lens

question

What is the Hubble classification for a spiral galaxy with a small nuclear region and loosely wound arms?

answer

Sc

question

What is the Local Group?

answer

A cluster of about 30 galaxies of which the Milky Way is a member.

question

What is the galactic halo?

answer

A spherical distribution of stars and globular clusters centered on the nuclear bulge.

question

What is the most outstanding feature of a quasar compared to other objects in deep space?

answer

Its enormous output of energy.

question

What method is used to determine the distances of very remote galaxies?

answer

Use of their spectral redshifts and the Hubble law.

question

What name is given to a galaxy with a smooth distribution of brightness and a round shape?

answer

E0

question

What name is given to a galaxy with a smooth distribution of brightness and a very elongated shape?

answer

E7

question

Where is the Sun located in our galaxy?

answer

In or close to the Orion arm, which is between the Sagittarius and Perseus arms.

question

Who developed the classification system that divides galaxies into spiral, elliptical, and irregular and classifies spirals by the size of their nuclear region and the tightness of winding of their arms?

answer

Edwin Hubble.

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