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: http://zebu.uoregon.edu/2003/ph301/l6.html
Дата изменения: Thu Oct 15 21:38:14 1998
Дата индексирования: Mon Oct 1 23:58:54 2012
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| The Scale of
The Universe How Big Is
It Really? | |
Background:
Brief History of the Size of the Universe
- Planets thought to define solar system size
- Stars held on spherical shell(s)
- Kepler estimates size of the solar system
- Thomas Wright (1750) makes spherical
shell model of the Galaxy
- Kant postulates Galaxy, other galaxies
- Messier sketeches nebulae
- Kant postulates nebular hypothesis for formation of
solar system
- Hershel defines Galaxy size with star counts
as
well as our apparent position in it.
- Parsons resolves spiral nebulae (sees them break up
into individual stars
- Kapteyn models the Galaxy based on star counts and star
brightnesses.
- Sir James Jeans theorizes that globular clusters are
the precursors of spiral nebulae.
- Slipher measures radial velocities of spiral nebulae.
- Energy sources of stars still unknown
- Age of the Earth estimated to be 2 billion years.
Shapley's View of our Galaxy and the Universe in 1920
Curtis's View of our Galaxy and the Universe in 1920
- Galaxy size similar to Kapteyn's: small and
flattened
- Spiral nebulae galaxies just like the Galaxy
- Didn't believe Shapley's Cepheid variable distances
Hubble to the rescue: