(E) Topic 16 Flashcards
How much of the universe is composed of dark matter?
25%
How much of the universe is composed of dark energy AND dark matter?
95%
What is dark matter used to explain?
Gravitational lensing
What is gravitational lensing?
The apparent ‘bending’ of light from galaxies to form multiple images of the same galaxy
What does WIMPS sand for?
Weakly interacting massive particles
What do people think dark matter exist in the form of?
Exotic particles called WIMPS
What are the major observational evidence in favour of the Big Bang theory?
- Quasars (QSOs)
- Cosmic microwave background (CMB) radiation
- Hubble Deep Field image
How does the existence of quasars support the big bang model?
Only found in HIGH redshifts
–> They lie great distances from us
–> Created when the universe was young
More common in the early universe compared to today
–> This supports the evolutionary nature of the Big Bang model
How does CMB radiation support the big bang model?
The CMB radiation from all parts of the sky was the same at a temp of 2.7K
How does the Hubble deep field (HDF) image support the big bang model?
And what is it?
Series of long exposure images of ‘empty space’ using the Hubble space telescope
Images revealed many thousands of very distant, therefore old, galaxies
–> Shows universe was very different from today
What is the steady state model of the universe?
The universe is and always has been expanding
New matter is constantly created
–> Overall density of the universe remains constant
What is the nature of density in the Big Bang model?
Density decreases over time
What is the Cyclic model of the universe?
There have been a series of ‘Big Bang’/ ‘Big Crunch’ scenarios which will continue in the future
