The Great Debate

Question 1

charles messier

Answer 1

1730-1817

-discovered his first comet at 14

Question 2

William Herschel

Answer 2

discovered Uranus in 1781

Question 3

The General Catalog of Nebulae and Star Clusters

Answer 3

herschel and his son discovered over 5000 nebulae and star clusters

Question 4

William Parsons

Answer 4

built largest telescope of 19th century

Question 5

Island Universes

Answer 5

Lord Rosse

-distinct spiral pattern

Question 6

who was the Great Debate between?

Answer 6

Heber Curtis & Harlow Shapley

Question 7

what was Great debate about?

Answer 7

nature of the spiral nubulae

Question 8

How big did Shapley think the MWG was and why?

Answer 8

100,000 pc across and Sun 30,000 pc from center

-measured distribution of globular clusters

Question 9

How big did Curtis think the MWG was and why?

Answer 9

Much less than 30,000 pc across and Sun was center

-found separate galaxy

Question 10

what did Curtis determine based on the Doppler shift?

Answer 10

the spiral nebulae were moving very rapidly (diff from most nebulae)

Question 11

who won the debate

Answer 11

draw

-neither was totally right nor totally wrong

Question 12

correct size of MWG

Answer 12

Shapley was correct, sun well off from center…size was too large

Question 13

Correct nature of the spiral nebulae

Answer 13

Curtis won hands down…spiral nebulae lie outside the Milky Way

Question 14

how could we prove that these really are distant “island universes”. What do we need to measure?

Answer 14

determining the distance to these spiral nebulae

Question 15

What did Edwin Hubble discover?

Answer 15

1924

-discoverde Cepheid variable stars in the Great Spiral Nebula in Andromeda using 100 in telescope

Question 16

What did Henrietta Leavitt discover in 1912?

Answer 16

the period-luminosity relation for Ceppheid variable stars

Question 17

what did Hubble measure in Andromeda?

Answer 17

brightness and period of pulsation

Question 18

what does the period provide?

Answer 18

luminosity, which combined with brightness gave Hubble distance to his stars

Question 19

where were the stars Hubble dealt with?

Answer 19

great spiral nebula

Question 20

size of today’s biggest telescopes?

Answer 20

10 m, or about 34 feet

Question 21

what are the 2 major types of galaxies?

Answer 21

spiral galaxies and elliptical galaxies

Question 22

what are barred spiral galaxies?

Answer 22

spiral galaxies w/ central bars

-spiral arms begin at end of these bars

Question 23

in spiral galaxies, disks and spirals have a substantial amount of what two things?

Answer 23

gas and dust

Question 24

new star formation in spiral arms come from?

Answer 24

hot gas

Question 25

properties of spiral galaxies?

Answer 25

disk & spheroid - spheroid has old stars and little gas/dust - disk has gas/dust, young

Question 26

properties of elliptical galaxies?

Answer 26

- only has spheroid component - mostly old stars - almost no gas/dust

Question 27

in which galaxy type can new stars form?

Answer 27

spiral galaxies like the MWG

Question 28

properties of irregular galaxies

Answer 28

- contain stars/gas/dust - no spheroid - star formation continuing

Question 29

size range of galaxies?

Answer 29

dwarf to giant

Question 30

galaxy clusters

Answer 30

when galaxies cluster together | -not uniformly distributed in space

Question 31

Poor clusters

Answer 31

- few cluster members | - irregular shape

Question 32

Rich clusters

Answer 32

- contains hundreds to thousands of galaxies | - spherical distribution

Question 33

What type of galaxies are in poor clusters?

Answer 33

dwarf irregular/elliptical

Question 34

what type of galaxies are in rich clusters?

Answer 34

elliptical and S0 galaxies

Question 35

Local Group

Answer 35

poor cluster contains MWG and two other spiral galaxies

Question 36

What are the remaining 40 galaxies?

Answer 36

all dwarf galaxies | -size=1 Mpc

Question 37

what size cluster is common?

Answer 37

poor galaxy clusters, or small galaxy groups

Question 38

what type of galaxy is common in rich clusters?

Answer 38

elliptical galaxies

Question 39

Abel 1689

Answer 39

- rich cluster - one of the largest galaxy clusters known - giant elliptical galaxies

Question 40

superclusters

Answer 40

clusters of galaxies are also clustered themselves