Advanced · 5 lessons
Galaxies and Cosmology
Connect galaxy observations with expansion, invisible matter and the early universe.
- 1
The Milky Way
The galaxy we inhabit must be mapped from within. That makes distance measurements, dust and viewing geometry central to the problem.
About 2 minutes reading · Advanced - 2
Galaxy Types and Evolution
Galaxy shapes summarize histories of gas supply, star formation and gravitational interactions. They are not a simple sequence of age labels.
About 2 minutes reading · Advanced - 3
The Expanding Universe
On large scales, distant galaxies show a systematic relationship between distance and redshift. Cosmology explains this pattern with an evolving scale of space.
About 2 minutes reading · Advanced - 4
Dark Matter and Dark Energy
These names describe two different problems in cosmology. Neither is a synonym for ordinary matter that happens to be hard to photograph.
About 2 minutes reading · Advanced - 5
The Big Bang and Cosmic Background Radiation
The hot Big Bang model describes an early hot, dense state and subsequent evolution. It does not by itself settle what, if anything, preceded that state.
About 2 minutes reading · Advanced
Put the ideas together
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