Astronomy 100 Exam 3

Front 1

The bottom up theory states that the galaxy formed...

Back 1

as a result of mergers between several smaller groups of gas, dust and stars.

Front 2

A dark region you see in the plane of the milky way is most likely to be produced by....

Back 2

a cloud of interstellar matter which contains dust particles.

Front 3

Open (galactic) star clusters..

Back 3

span a wide range of ages, some are quite young.

Front 4

What property do galaxies, start clusters, and stars have in common?

Back 4

(all of the above)
held together by gravity
condensed out of clouds of gas
are composed mostly of hydrogen

Front 5

Edwin hubble recognized that the Andromeda nebula was a seperate "island universe" rather than a component of our own galaxy because..

Back 5

he used cephied variables to find it was a tremendous distance away

Front 6

Which of the following is a characteristic of the halo component of the milky way?

Back 6

randomly inclined stellar orbits

Front 7

Harlow shapely used globular clusters to show that the ...

Back 7

solar system is located far from the center of the milky way

Front 8

Astronomers use cephied variable stars to measure galaxies dtances because....

Back 8

thei luminosity can be determined from their period of variation

Front 9

based on the rotation curves of stars in spiral galaxies and the milky way, most of the mass in the galaxies is believed to be in the form of...

Back 9

dark matter

Front 10

Younger star have more heavy elements because

Back 10

heavy elements were made in the previous generation of stars

Front 11

______ galaxies contain large clouds of gas and dust, both young and old stars, but have no obvious spiral arms or nucleous.

Back 11

irregular

Front 12

The milky way galaxy is part od

Back 12

the local group

Front 13

hubbles law

Back 13

(all of the above)
tells us that the universe is expanding
the universe was much smaller in the past
neasure distance of distant galaxies and quasars
more distant galaxies recede more rapidly than nearby ones

Front 14

The rotation curve of a galaxy can be used to determine

Back 14

the mass of a galaxy

Front 15

Supermassive black holes are believed to be present in the center of

Back 15

(all of the above)
quasars
milky way
active galaxies

Front 16

An elliptical galaxy could

Back 16

be formed from the collision and merger of spiral galaxies

Front 17

for which of the follwoing objects does hubbles law work?

Back 17

distant galaxies

Front 18

choose the best answer from the following: the one with the lease amount of gas or dust:

Back 18

elliptical

Front 19

quasars must be small because they

Back 19

have luminosities that fluctuate rapidly

Front 20

If the red shfts of quasars arise from the expansion of the univers

Back 20

a quasar must be very luminous

Front 21

Where is the center of the universe?

Back 21

There is no center

Front 22

Our galaxy is one of about thirty members of this collection of galaxies

Back 22

local group

Front 23

at 750 kpc away

Back 23

andromeda galaxy

Front 24

a collection of thousands of galaxies centered about 15 mpc away from us

Back 24

virgo cluster

Front 25

the cosmic background radiation comes frmo a time in the evolution of the universe

Back 25

when electrons began to recombine with nuclei to form atoms

Front 26

whether the universe is open, closed or flat depends on the _____ of the universe

Back 26

density

Front 27

the age of the universe can be determined if

Back 27

the hubble constant and density of the universe can be accurately determined

Front 28

if H equals 50 km/sec/mpc then a galaxy with a radical velocity of 2000 km/sec probably has a distance of

Back 28

40 mpc

Front 29

if the space telescope proved that hubbles constant is actually half as large as it is currently believed to be the implied age of the universe would be ______ the currently accepted value

Back 29

two times

Front 30

the universe is said to be closed if

Back 30

gravity is strong enough to stop the expansion in a finite time

Front 31

one quarter of the mass of the universe today is helium. this helium was produced

Back 31

by nuclear reactions occuring a few minutes after the big bang

Front 32

the hydrogen balmer line Hb has a wavelength 486.1nm in the lab it is observed in a quasar at 2430.5nm what is the shift of this quasar

Back 32

4

Front 33

a recently formed cluster of stars might be identified by the presence of

Back 33

(all of the above)
bright blue stars
dusty patches hiding parts of the cluster
glowing gas between the stars
reflection nebulae around some stars

Front 34

if galaxy A is four times more distant than galaxy B then according to the hubble law galaxy A will recede _____ than galaxy B

Back 34

4x faster

Front 35

besides hubbles observation of the expanding universe the best evidence for the big bang comes from

Back 35

the cosmic microwave background and the amount of helium, in the universe