Science 9 Questions: Chapter 10.1 ReviewP346-352

1. What did Edwin Hubble notice about the direction of movement of galaxies in space?Galaxies appeared to be moving away from each other with the farthest ones from us moving at the fastest speeds. Also, if the path of each galaxy’s motion were traced back to where it had been before, the paths of the all the galaxys came to a single point in space.

2. What conclusion did Hubble make when he observed that distant galaxies appeared to be moving away from each other?

He concluded that they were together in some way at some earlier time and a massive explosion drove them apart.

3. Name four types of electromagnetic radiation.Visible light, microwaves, radio waves and X rays

4. What is a spectrum?A spectrum is the pattern of colours coming from an object giving off electromagnetic radiation (some form of light).

5. What is indicated by a shift of a galaxy’s spectral lines toward the red part of its spectrum?The galaxy is moving away

6. What did Edwin Hubble discover about the spectra of the galaxies he observed?Hubble noticed that spectral lines were shifted towards the red end of the spectrum.

7. What do we call radiation that is carried in the form of waves?Electromagnetic radiation

8. What is the purpose of a spectroscope?A spectroscope makes light spread out into a spectrum. It separates the various waves travelling together.

9. What does the cosmological red shift suggest about the motion of galaxies?The galaxies are expanding outward from a point. The universe is expanding.

10. State the main idea of the Big Bang theory.All matter was very concentrated at one time in a fairly small region of space. It suddenly expanded to a very large size and pushed everything out from the centre. As the matter moved outward, it formed atoms and these eventually made galaxies, stars and planets.

11. Give one piece of evidence that supports the Big Bang theory.All sky objects appear to be moving outward (their light red-shifted) with the farthest moving the fastest.

Science 9 Questions: Chapter 10.1 ReviewP346-352

12. According to the Big Bang theory, how did the temperature of the universe change as the universe expanded?

At first the temperature was extreme but as the expansion continued, matter cooled so that at the outermost edges of the universe matter is only a few degrees above absolute zero, the lowest temperature possible.

13. What evidence did Edwin Hubble use to suggest the universe was expanding?The fact that the most distant sky objects from us have the greatest red-shifts of their spectral lines while closer sky objects show smaller red-shifts is consistent with an expanding universe.

14. How is a loaf of raisin bread baking in the oven a simple model of Hubble’s view of an expanding universe?

As the loaf expands as it is baked, raisins closer to a given raisin seem to move away less far than do raisins farther away from the given raisin which seem to move farther away.

15. Both the COBE satellite and WMAP were designed to measure temperatures only a few degrees above absolute zero. Why was it necessary to take these measurements in space rather than than from Earth?

The heat on Earth and in its atmosphere would interfere with the sensitive satellite instruments and make the temperature readings of distant space objects appear to be much higher than they really are.

16. How does the pattern shown in the WMAP map indicate that the presence of microwave radiation in the universe is not the same everywhere?

The blue regions are denser regions of early space where galaxies are thought to have formed. Red areas are less dense regions that have becomed emptier and emptier as time has progressed.

17. How does cosmic background radiation provide evidence for the Big Bang theory of the origin of the universe?

If there was some kind of explosion that started our universe then one would expect the remains of this to be pushed out on the very edge of our expanding universe. As it cooled, it would be a faint afterglow of an original fantastic blast. We find everywhere at the edges of our universe in all directions a faint glow, a “noise-like” (unorganized) radiation of microwaves. This faint light energy is called the cosmic background radiation because it is found throughout our cosmos (universe) at its farthest edges.

Science 9 Questions: Chapter 10.1 ReviewP346-352

18. Why is cosmic background radiation important in the study of the formation of galaxies?This kind of radiation would indicate the formation of atoms and eventually galaxies if the radiation were somewhat uneven rather than totally even. The WMAP probe has taken photos of the microwave radiation at our universe’s edges that indicate the kind of unevenness needed to form galaxies.