Basic Idea: Contents: where and what, scales
The measured effects of the cosmological constant
are primarily in the field of cosmology, the study of the
universe as a physical system.
In order to provide a context for the various subsequent
sections, this section will describe many of the objects
in the universe and relative sizes, and the next section
will very briefly summarize the current paradigm for the
history of the universe. Note that cosmological
inventory is still underway at the frontiers of
Interest here is in subset of astronomical objects,
many of which are quite large.
Cosmic Voyage and powers of 10: relative sizes
Some Objects and Scales
What are they made of?
- nearby objects
- solar system
- next nearest star
- milky way
- cosmological objects
- super cluster
- note: mapping out the universe locally and beyond is
a major current research project
Some other objects used in later sections:
- familiar matter: baryons, photons, neutrinos
- Types: hot, cold
- Exotic particle candidates--particle physics has many
possible suggestions but
no particle physics detections either direct or indirect yet.
Many searches are underway.
Difficult-not clear where to look given their weak interactions
Current issues: self interactions, how light traces mass
- Combined matter content picture
- globular clusters
- black holes/supermassive black holes/quasars
- lyman alpha forests
Wavelengths/observations: radiation is all around us!
- photons: spectrum
finite speed of light: look at large distances, seeing back in time
examples--how far corresponds to how long ago in terms of z, pc
distance to farthest visible objects
search for earliest objects (farthest) underway by many groups
- cosmic rays
- gravity waves