Chapter 29: Cosmology Flashcards
What is cosmology?
the study of the universe including its structure, history, origins, fate
What is the cosmological principle?
the physical laws and the properties of the universe are the same everywhere (homogeneous) and in all directions (isotropic)
Hubble’s Law meaning
The farther away a galaxy is, the farther it is moving away
What are the 4 main pieces of evidence for the Big Bang theory?
Cosmological Redshifts of Galaxies. Cosmic Microwave Background radiation, Formation of large-scale structures in the Universe, Abundances of hydrogen and helium
What are cosmological redshifts of galaxies?
the larger the distance to the galaxy the larger its recession to velocity (the universe is an expansion of space itself)
What is the cosmic microwave background?
As the universe expands from a hot dense point the temp of space-time decreases. radiation = cmb
What is the abundance of hydrogen and helium?
Everywhere in the universe, there is about 25% of the mass of ordinary matter in helium.
What does our universe not have?
A center or edge
What is the CMB temp now?
3K
What is the Era of recombination?
temp high before recombination, temp low after recombination
How are Type 1a supernovae used to show the presence of dark energy?
things are getting further faster than expected?
What does dark energy do?
It accelerated expansion
How old is the universe?
13.7 billion years old
How many years after the big bang is the CMB from?
400,000 years
When was the first star ignited?
400 million years after the big bang
