galaxies
TRANSCRIPT
The Milky Way
The Milky Way is a prominent band of light across the sky
The Milky Way Panorama
Credit: Addison Wesley
Structure of The Milky Way Galaxy
Total number of stars: few x 100 billions
M51 Whirlpool Galaxy 渦狀星系
Credit: NASA and The Hubble Heritage Team (STScI/AURA)
Spiral Arm 旋臂距離: 3100萬光年直徑: 3萬光年
Current View of the Milky Way
Credit: NASA/JPL/R. Hurt
Sir Frederick William Herschel 赫歇爾 (1738-1822)
48-inch reflector
DSpace@Cambridge7
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Nebulae drawn by William Herschel
The Leviathan of Parsonstown 帕森城海怪
The largest telescope in the 19th century, with a 1.8m mirror. It was built by William Parsons, 3rd Earl of Rosse on his Castle in 1845.
Credit: Pearson Prentice Hall, Inc.
Standard Candles - Cepheids 造父變星
Credit: Robert Gendler
M31 Andromeda Nebula 仙女座大星雲
Galaxy 系
CCST9012
Our Place in the Universe
Some of the globular clusters (circled) surrounding the Milky Way
Mt. Wilson 60-inch telescope built in 1908
http://www.astro.caltech.edu/palomar/history.html
Are we at the center of the Milky Way?• Shapely determined the distances to 69 globular clusters and mapped their
distribution in space by using the Cepheids as distance markers.• If globular clusters were uniformly distributed in the Milky Way, then his data
suggested our Sun is not in the center but off to one side of a flat disk of stars.
http://www.aip.org/history/cosmology/ideas/island.htm
Our Sun
Center