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Miss Nevoral
Science 9
Space Unit
http://www.sd23.bc.ca/~lnevoral
Chapter 10 – Evidence that Universe Formed 13.7 Billion Years Ago
KEY
Name: _____________________
Date: ____________
Block: ________
Section 10.1 – Explaining the Early Universe (pages 346 – 355)
1. Define astronomers: People who study space and objects in space.
2. Explain why scientific theories are not considered the final truth/fact about
something. Theories are developed with existing information. The main
ideas about a theory may change if new evidence arises or there is a
breakthrough with technology, etc. Therefore, we can not say that a
theory is a fact because more evidence may be found to change that
theory.
3. Define celestial bodies: General term for all objects in the sky  Sun,
moon, planets, and stars.
4. The development of the telescope allowed astronomers to see more celestial
bodies.
5. Who was the first astronomer to identify other galaxies besides the Milky Way?
What did he notice about the direction of movement of galaxies in space? What
conclusion did he make when he observed this direction of movement? Edwin
Hubble was the first astronomer to identify other galaxies. He noticed
that galaxies appeared to be moving away from each other and that the
universe was expanding. He discovered this by using a tool known as red
shift analysis.
6. Draw and explain what Figure 10.1 on page 346 is trying to represent in the box
below.
The figure is trying to show that galaxies
are moving away from Earth and that
galaxies farther away are moving faster
than galaxies closer to ours.
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7. Define electromagnetic radiation: Energy that is carried in the form of
waves.
8. Name four types of electromagnetic radiation. Radio waves, microwaves,
infrared radiation, visible light, UV radiation, X-rays, gamma rays.
9. What is a spectrum? Explain the use of a spectroscope. White light splits
into a pattern of colours and this is called a spectrum. A spectroscope
separates light into its basic components. It allows the user to view the
spectral lines produced by stars and galaxies and to measure their
wavelengths.
10. What does the cosmological red shift suggest about the motion of galaxies?
The cosmological red shift suggests that galaxies are moving away from
each other.
11. Who first proposed the Big Bang Theory and in what year? Georges Lemaitre
first proposed the Big Bang Theory in 1927.
12. State the main idea of the Big Bang Theory. The theory suggests that 13.7
billion years ago a tiny volume of space with high mass suddenly and
rapidly expanded to immense size. In a very short time, all the matter
and energy in the universe was formed.
13. According to the Big Bang Theory, how did the temperature of the universe change
as the universe expanded? The universe cooled as it expanded.
14. What does COBE and WMAP stand for? COBE  Cosmic Background
Explorer; WMAP  Wilkinson Microwave Anistropy Probe
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 from Earth? The Earth’s atmosphere is
warm, making detection of extremely low temperatures (like those found
in space) very difficult.
16. How does cosmic background radiation provide evidence for the Big Bang theory of
the origin of the universe? Cosmic background radiation is leftover radiation
from the initial explosive expansion of the universe which would support
the idea of the Big Bang theory.
17. Why is cosmic background radiation important in the study of the information of
galaxies? Dark areas of WMAP indicate dense areas of the early universe.
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Astronomers hypothesize that these patches show where galaxies were
formed.
Section 10.2 – Galaxies (pages 356 – 363)
1. Define galaxies: An enormous collection of gases, dust, and billions of
stars held together by gravity.
2. What is the name of our galaxy? What shape is our galaxy? Our galaxy is the
Milky Way. It is a spiral galaxy.
3. What is a nebula and what is the difference between it and a galaxy? A nebula is
a cloud of gas and dust in space. It is different from a galaxy because a
nebula is where stars are born and a galaxy is a large collection of stars.
4. What galaxy is our nearest neighbouring galaxy? Andromeda
5. Identify the type of galaxy shown in each sketch. Write your answer beneath each
one. 1. Spiral 2. Spiral from its side 3. Elliptical 4. Irregular
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6. What characteristics do all galaxies share? Galaxies are large, contain stars,
spinning.
7. How does the speed at which a galaxy rotates affect its shape? The more spin a
galaxy has, the flatter it will be.
8. Besides shape, what other ways do galaxies differ from each other? Galaxies
differ in size, mass, brightness, colour, and speed of spin.
9. Describe the two different types of star clusters galaxies may contain. Globular
cluster  as many a 1 million stars, held together by their mutual gravity
in a spherical shape. Open cluster  only a few hundred to a few tens of
thousands of stars.
10. What is “galactic cannibalism”? When galaxies get too close, the
gravitational force of a larger galaxy can pull apart a smaller galaxy.
Eventually, the big galaxy will pull the pieces of the smaller galaxy into
its own structure.
11. How do the millions or billions of stars of a galaxy stay together? Gravity
12. Image that an astronomer is observing a group of three galaxies. If the spectrum
of each of the galaxies is shifted towards the blue end, what can the astronomer
conclude about the galaxies? That the galaxies were moving towards each
other (shorter wavelengths).
13. List the following in order of size, from smallest to largest:
 universe
 nebula
 galaxy
 star
Star, nebula, galaxy, universe
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