1. In 1800s
1.1. More Improving
1.1.1. Telescopes
1.1.1.1. Revealed More About Nebulae
1.1.1.1.1. Appearance
1.1.1.1.2. Challage
2. Astronomy
2.1. Basic Science
2.1.1. Solely Concerned
2.1.2. Understanding of the natural world
2.2. New Technologies
2.2.1. Increase to make careful observations
2.2.2. Lead to new understandings
3. William Huggins ( In 1864 )
3.1. Spectroscope attached in telescope and aimed at Nebulae
3.2. Spectroscope
3.2.1. Has unique spectrum line
3.2.2. Can tell the elemental makeup of celestial objects
4. Astronomers Argued that Nebulae are made out of stars
4.1. Based on 1885 ( Nova in the Andromeda Nebulae )
4.2. 'Nova' ( New Stars in Latin )
4.3. thought bright objects to be stllar newborns
5. Julius Scheiner ( In 1898 )
5.1. Used spectroscope on the Amromeda Nebulae
5.1.1. Had a similar spectrum to the Sun
5.1.1.1. Most astronomers think nebulae are composed of stars
6. In1900s
6.1. Over 100,000 Nebulae are Detected
6.1.1. Other Astronomers continued to think that Nebulae are "Isaland Universes"
6.1.2. Astronomers focused on the distances of the Nebulae
6.1.2.1. Astronomer F.W
6.1.2.1.1. Assumed that Milky Way and the Andromeda Nebula are similar in size
6.1.2.1.2. By comparing their brightness about 3800 light-years apart
6.1.2.2. Other Astronomers felt that the Milky Way was far larger than 120 light-years
7. Max Wolf
7.1. Concluded most Nebulae are 1,000 light years in diameter
8. Uniformity in nature
8.1. Assumption claims that processes and like objects are uniform thorughout the nature regardless of location
8.1.1. Nebulae
8.1.1.1. Categories
8.1.1.1.1. Enternal
8.1.1.1.2. Internal
9. William Wallace Campbell ( In 1911)
9.1. Age of the stars and veloctiy
9.1.1. The older the star, the higher of it's velocity
9.1.2. would have similar speed like young stars
9.1.3. Rejected but continued to study in decade and streghten the evidence that the Andromeda Nebula is an Island Universe
9.1.4. Recheck his work asking Sliper, in 8 years debated in the Great Debate
9.1.4.1. Curtis beat him on the materials of the subject
10. In 1920
10.1. Debate where Curtis didn't want to participate
10.2. Try to avoid humiliated by more experience Curtis
11. Henrietta Leavitt ( In 1912 )
11.1. Luminostiy was known 'standard calndles' to determine distance
11.1.1. The apparent magnitude
11.1.1.1. brightness of a star from earth
11.1.2. The absoulte magnitude
11.1.2.1. Seen from 10 parsecs ( 30 light years )
11.2. m- M = 5 log r/10
12. Eddie Hubble
12.1. Had eyes on veryfying the island universe model
12.1.1. By locating a variable star within a nebula
12.2. In 1923 he discovered Cepheid variable stars in the Andromeda Nebula
12.2.1. For atleast 300,000 parces three times larger than Shapely's Big Galaxy
12.3. January 1, 1925 published his work and continued to his research on nebulae
13. Debation In Academy
13.1. Harlow Shapely ( April 26, 1920 )
13.1.1. Island Universe
13.1.1.1. Milky Way (Claimed ten times bigger)
13.1.1.2. Big Galaxy
13.2. Herber D. Curtis ( Opponent )
13.2.1. "Great Debate"
13.2.1.1. Academy published newspapers in 1921
13.2.1.2. Both had well-founded agruements
14. Edwin Hubble (In 1924)
14.1. Concluded that Isalnd Univserses is real
15. Late 1700s
15.1. Improving
15.1.1. Telescopes
15.1.1.1. Tele
15.1.2. Sky Watchers
15.2. Viewing
15.2.1. Planets
15.2.2. Comets
15.2.3. Asteroids
15.2.4. Stars
15.3. Identifying
15.3.1. Unidentified class of fuzzy objects
15.3.1.1. Nubulae ( 'Cloud' In Latin )
15.3.1.1.1. Speculated ( By A Early Astronomers )
16. Lord Rosse ( In 1840s )
16.1. Used giant telescopes to discern individual stars in nebulae
17. John P. Nichol
17.1. In Scotland
17.1.1. Swore that the clouds were some sort of luminous fluid
18. Most astronomers think nebulae are composed of stars
18.1. But Actually in the process of forming stars
19. In 1910s
19.1. Determind that nubalae is 30,000 years lighter
20. Beginning of 20th Century
20.1. Accepeted that Nebulae is made of stars
20.2. Many stars varied in respect to their luminosity
20.3. Cephied Varialbles
20.3.1. had a notable relationship between the period of their veriability and luminosity.
21. Vesto Slipher ( In 1909 )
21.1. Measuring velocity of Nubalae
21.1.1. Radial velocities
21.1.1.1. Rates of movement object directly or away from observer
21.1.2. The Doppler Effect
21.1.2.1. Oncoming object
21.1.2.1.1. Shifted into blue end "Blueshift"
21.1.2.1.2. Objects moving towards observer shift
21.1.2.1.3. Shorter wavelengths
21.1.2.2. Receding object
21.1.2.2.1. Shifted into red end "Redshift"
21.1.2.2.2. Objects moving away from observer shift
21.1.2.2.3. Longer wavelengths
21.2. Measured that the Andromeda Nebula to moving forward the Milky Way of 300 kilometer per second
22. Adriaan van Maanen ( In 1915 )
22.1. Measuring the internal rotational motions of Nebula M101
22.1.1. Shapely and van Menaan work together
22.1.1.1. Shapely supported island univesrse idea until Milky Way is 300,000 light years in diameter
22.1.1.2. Applied van' menaan rotational motions as evidence needed against island universes
22.1.1.2.1. Shapely and van Menaan became the most vocal opponents of island universes
23. In 1920
23.1. Island Universe
23.1.1. Nebulae moved far faster than stars
23.2. Big Galaxy
23.2.1. Collected evidence that Island Universe is physically impossible