2. A group of billions of stars held together by gravity is called a ...
A. solar system
C. white dwarf
3. Which of the following lists has objects in order of increasing size?
A. solar system, universe, galaxy
B. solar system, galaxy, universe
C. universe, galaxy, solar system
D. galaxy, solar system, universe
The Big Bang
4. The 'Big Bang' (beginning of the Universe) released an enornouse amount of radiation. This 'cosmic background radiation' can still be detected. In which region of the electromagnetic spectrum is it found?
C. radio waves
5. In which direction does this radiation come from?
A. The centre of the Universe
B. The centre of our galaxy
C. The nearest black hole
D. All directions
6. As the Universe has expanded and cooled, what has happened to the wavelength and intensity of this cosmic radiation over time?
7-10. The paragraph below describes other evidence for the 'Big Bang'.