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T/F Our Sun lies about 300,000 light years out from the Galactic Center


T/F The Earth lies close to the center of the Galaxy


the longer the period of pulsation for the Cepheid, the more massive and luminous the variable giant star is


True or False William Herschel's original model for our Galaxy was based on counting stars.


Herschels original disk model placed use close to the center of the galaxy.


The instability strip is above teh main sequence on the H-R diagram


William Herschel made the fist map of the Galaxy about 200 years ago


True or False RR Lyrae stars pulsate, but with shorter periods and lower luminosiites than cepheids


True or False It is harder to map the structure of the Milky Way in visible wavelengths than with radio and infrared waves


T/F Shapley found the globulars were strongly concentrated toward Sagittarius


Shapley found that globular clusters are only found in the Galactic bulge

come back

Harlow Shapley mapped the Milky Way using the period luminosity relationship for RR Lyrae stars


T/F 21-cm radio waves allow us to map the distribution of hydrogen in spiral arms on the opposite side of the Galaxy


T/F Halo stars are all Population II objects


The orbit of the solar system around the Galaxy is similar to that of a planet, almost circular and in the galactic plane


stars with an emission nebula such as m42 are considered


The thickness of the Galaxy, near the SUn, is aout 1000 light hers pulsation I stars


The globular star clusters are the most obvious examples of population II around us


Population I stars came billions of years before population II stars


Halo stars are all population II objects


the RR lyre stars all have periods of

a few hours

a star in the instability strip of the H-R diagram would

vary in both temperature and raidus

for finding the distances to globular clusters, Harlow Shapley used

RR Lyrae variables

Which is the correct description of the Sun's location within the Milky Way

above the disc and about one-third of the galactic radius from the center

Galactic disks appear blue because

O and B blue giants are much brighter than G, K, or M dwarfs.

The Galactic Year is the time for our solar system to orbit the Galaxy; it is about

225 million years

Detailed measurements of the disk and central bulge region of our Galaxy suggest our Milky Way is a

barred spiral galaxy

Between us and the Galactic Center, the Milky Way has a mass of

100 billion suns

In the formation of our Galaxy, the formed first

globular clusters?

Which sequence of formation is best, oldest to youngest

Globular clusters, open clusters, OB associations

Most of the new star formation in the Galaxy is found in the

spiral arms

Most of the mass of the Milky Way seems to exist in the form of

dark matter out in the Halo

At the center of our Galaxy lies

A black hole of millions of solar masses

The radio source blank is located in a place consistent with the center of our Galaxy

Sgr A*

What are the three main parts of our Galaxy?

Galactic Disk Globular clusters, Halo

Describe our location in the Milky Way

he Milky Way's outer spiral arms, known as the Orion Arm or Local Spur. The Sun lies between 25,000 and 28,000 light years from the Galactic Centre.

What do the orbits of Populations I and II stars tell us about the formation of the Milky Way?

the metallicity of the star

How and when did the Miky Way Galaxy form?

The milky way was formed by stars gases and dust . The milky way also started as a black hole and stars dust and gases gathered around the black hole. When? with our current astronomical knowledge, scientists predict it was approximately 1 billion years after the big bang

T/f Compared to the spirals, elliptical galaxies tend to be more dusty


T/f Unlike spirals, elliptical galaxies do not contain a flattened disk.


T/f There are more giant elliptical than dwarf galaxies


T/f Most galaxies are spirals.


T/f Irr II galaxies may be the result of a collision, or close encounter, of two normal galaxies


T/f On average, elliptical galaxies are richer star forming regions than spirals.


T/f In the Local Group, most members are either dwarf ellipticals or spirals.


T/f The closest other galaxy to our solar system is the Sagittarius Dwarf.


T/f While our Magellanic Clouds are irregulars, the two companions to Andromeda are both ellipticals.


T/f Virtually all galaxies are moving away from the Milky Way.


T/f Space itself is expanding.


T/f Quasars can emit thousands of times as much energy as normal galaxies.


T/f Quasars are the brightest objects in the universe.


T/f When observing a quasar, we are probably looking at a stage of evolution in the very early universe.


T/f Radio galaxies emit only radio waves, and are not otherwise observable.


On average, active galaxies are rare and most are fairly distant from us.


There is evidence that a collision between a spiral and an elliptical galaxy has produced a radio galaxy.


Synchrotron radiation is the major source of energy for active galaxies.


Which property is common to spiral galaxies?

on-going star formation and emission nebula in the arms

The astronomer who originally classified galaxies into S, E, and Irr was

Edwin hubble

Compared to our own Galaxy, elliptical galaxies

have no arms, but a better defined disk

The Milky Way is often considered to be an intermediately wound, barred spiral, which would be type ________ according to Hubble.


The flattest of all galaxies belong to class


In shape and component stars, elliptical galaxies are most like our own

Galactic center

What is true of giant and dwarf elliptical galaxies?


The greatest variation in size, mass, and luminosity occurs in

elliptic galaxies

What is true of the Local Group?

The milky way and the andromeda galaxy are two of the largest members of the local group.

About how many galaxies are presently known in our Local Group?


Why does the Cepheid distance method fail us beyond about 20 Mpc?

Even with the HST, the most luminous Cepheids are too faint to be seen beyond.

What is the nearest huge cluster of thousands of galaxies, to which the Local Group may belong?

Virgo Cluster

What are Type I supernovae used for?

Standard candles for determining distances to other galaxies.

Which statement about the Magellanic Clouds is false?

They are close to the south pole of the sky

Most of the galaxies in the Local Group are

small irregulars like the Magellanic Clouds

According to Hubble's Law, the greater a galaxy's redshift, the

farther it is from us.

A billion-solar-mass black hole would still have a radius of only


The energy radiated by a typical quasar requires that its black hole accrete about

Ten solar masses a year

Not only does the central engine of active galaxies and quasars require a black hole, but also ________ to provide the radiate energy.

an accretion disk of infalling matter

When mass is accreted into a black hole, how much total mass-energy can be radiated away?

The whole of its gravitational potential energy

Who invented the galaxy classes, and what three major groups did he invent? Which telescope did he use?

Edwin hubble. ellipticals, lentriculars and spirals. Hubble space telescope

To which portion of the Milky Way are the Magellanic Clouds most similar? Why?

the closest similarity would be to the arms of the Milky Way - the Magellanic Clouds themselves are small irregular satellite galaxies of the Milky Way and contain many of the same features found in the spiral arms - nebulae, star clusters, supernova remnants, etc

Why do quasars die out over time?

they get all the gas and then run out and become black holes

Most of the mass in the universe is dark matter.


There are large amounts of superhot intergalactic gas/matter


As with stars, binary galaxy pairs are useful in finding their total mass


For nearby galaxies, determing the rotation curve allows us to calculate the mass


The total mass of a galaxy tends to be only slightly larger than the visible mass


Head-tail radio galaxies reveal their motion through the intergalactic gas with a tail like structure


The Great Wall is a huge sheet of galaxies that stretches for over 100 Mpc


Galaxies contain less mass as dark matter than as visible stars


The largest known galaxies contain about 10 billion solar masses


The Andromeda galaxy will eventually collide with the Milky Way


Collisions between galaxies have little effect on the individual stars.


Galactic collisions are believed to be commonplace.


In the larger clusters, colliding galaxies tend to pass through one another


When galaxies collide, the large scale galactic structure if affected, but the individual stars are not


Our theories of galaxy formation are just as well developed and tested as are our theories of star and planet formation


Most galaxies are isolated in space


The pregalactic blobs started with masses comparable to big globular clusters


Supermassive galaxies are found at the core of rich galaxy clusters.


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