Download U7 Review WS KEY

Name _____KEY_____________ Date _________
Period ______
Formation of the Universe Review Sheet
1. I can describe the basic structure, properties and classification of stars.
 Name the two most common elements in stars. hydrogen and helium
 State two reasons why one star may appear brighter than another star.
Larger and/or closer to earth
 List, sketch and be able to identify the life stages for a low mass star.
Nebula > main sequence star > red dwarf > white dwarf > black dwarf
 List, sketch and be able to identify the life stages for a very high mass star.
Nebula > main sequence star > red giant > supernova > black hole or neutron star
 Explain why the sun does not collapse under the force of its own gravity.
Pressure from energy released by nuclear fusion pushes out
 What marks the transition of a protostar to a star?
a. the end of nuclear fusion
c. the beginning of nuclear fission
b. the beginning of nuclear fusion d. the end of nuclear fission
 What is a star made of?
a. gases
b. liquids
 Some of the light that radiates from a star
a. is absorbed by elements in a star’s atmosphere.
c. is absorbed by other stars.
 How can scientists identify a star’s elements?
a. by its color
c. by its light
b. by its shape
c. solids
d. gases and solids
b. is absorbed by the star’s inner layers.
d. is emitted through the universe.
d. by its age
 Why are scientists able to use spectra to determine the composition of stars?
a. because all stars have the same composition as Earth
b. because every chemical element has a characteristic spectrum
c. because chemical elements do not have characteristic spectra
d. because colors and lines in the spectrum of stars are all the same
 How bright a star appears as seen from Earth is called _absolute magnitude_ .
 Astronomers use _light years_ to measure distances from Earth to the stars.
 Which of the following statements is NOT true of supernovas?
a. They are explosions in which a massive star collapses.
b. They are explosions that occur at the beginning of a star’s life.
c. They can be brighter than an entire galaxy for several days.
d. They are explosions in which a star throws its outer layers into space.
 A rapidly spinning neutron star is called a(n) __quasar___ .
 An object so massive that light cannot escape its gravity is a(n) _black hole_.
2. I can explain how the surface temperature of stars is measured.
 Explain how the color of a star is related to its temperature.
Red stars are cooler and blue stars are hotter.
 The hottest stars are
a. yellow
b. orange
c. red
d. blue
3. I can explain how fusion reactions form elements in normal stars.
 Describe how elements are formed in stars.
When pressure and temperature are high enough, smaller atoms are fused into larger atoms.
 Explain how a star produces energy.
Nuclear fusion releases enormous amounts of energy.
4. I can describe the evolution of stars by creating and interpreting a Hertzsprung-Russell diagram.
**List the four named stars on the HR Diagram above in order from the lowest
to the greatest magnitude. Sirius B, Capella, Spica, Deneb
**For each star type in the H-R diagram, state the relationship between and temperature
and brightness. Sirius B: low M, mid-range T; Capella: mid-range M, low T;
Spica: high M, high T;
Deneb: high M, mid-range T
**On what part of the H-R diagram would you find the majority of the main-sequence stars?
mid-range M and T
**Define luminosity and absolute magnitude. luminosity: how much energy leaves star/time;
absolute magnitude: brightness at same distance from earth
Small, hot star in final stage of its life cycle _white dwarf__
Star in second and longest stage of its life cycle _main sequence star__
Large, cool star in third stage of its life cycle _red giant__
Stars with low mass, low temperature, and low absolute magnitude _red dwarf_
Small hot stars that are dimmer than the sun _white dwarf_
High-temperature stars that quickly use up their hydrogen _blue giant_
5. I can define galaxy and distinguish between 3 types of galaxies. group of stars held by gravity
 What are the three types of galaxies?
 Describe the basic shape of each.
spiral: swirled with “arms”; elliptical: egg-shaped; irregular: no definite shape
6. I can describe quasars and identify the tools used to study quasars.
spinning neutron stars that emit radio waves in pulses.
7. I can describe the basic structure of the universe.
 Despite all the gas, dust and stars in the universe, the universe is still mostly _empty space_.
 The sum of all matter, energy and space is _the universe_.
 Why do we think that dark matter exists? not enough visible matter in universe to account for
effects of gravity due to mass.
 Einstein’s general theory of relativity states that mass can_bend space and time_.
8. I can describe the red-shift phenomena and the information it provides about the universe.
 Explain the relationship between the Doppler effect and red shift and blue shift.
When a light-emitting object moves, the light waves in front of the object are compressed
causing the frequency to be higher (bluer) and the light waves in back of the object are stretched
out causing the frequency to be lower (redder). Objects moving away from earth have redder light.
9. I can state the main features of the big bang theory and explain evidence that supports the
expansion of the universe.
 Describe the big bang theory. What are 3 lines of evidence for the big bang?
red-shifted light spectra from galaxies = they are moving away; cosmic background radiation;
most of universe mass is H and He = the first elements formed in initial explosion.
 Scientists think that the universe is expanding at an accelerating rate. Why?
light spectra from galaxies are red-shifted; galaxies farther away are moving away faster.
 What did Hubble discover that indicated that the universe is expanding?
a. Only stars in the main sequence are moving away from Earth.
b. Galaxies are moving closer to Earth.
c. Spectras of galaxies were shifted toward the blue end.
d. Spectras of galaxies were shifted toward the red end.
 Radiation left over from the big bang is called
a. cosmic radio waves
c. gamma ray bursts
b. cosmic microwaves background radiation d. cosmic x-ray radiation
 About how long ago did the big bang occur?
a. 4.6 billion years ago
c. 13.7 billion years ago
b. 10 billion years ago
d. 100 million years ago
 The Big Bang theory states that the universe began when a dense, hot, super massive
singularity violently exploded.
a. steady state theory
c. big bang theory
b. string theory
d. big crunch theory
 Which is NOT evidence to support the big bang theory?
a. red shift of galaxies
c. galactic clusters
b. cosmic background radiation
d. abundance of light elements (H, He and Li)
 The first elements that were formed in the universe were?
a. hydrogen and lithium
c. hydrogen and helium
b. lithium and helium
d. lithium and beryllium
10. I can describe tools and models used by scientists to predict the future of the universe.
 Describe the three possible outcomes for the universe.
1. keep expanding
2. expand then stop expanding 3. expand then collapse
 Space based telescopes, such as the Hubble Space Telescope, allow astronomers to see
further away than they can with telescopes on Earth. Seeing more distant objects is in
effect equivalent to seeing
a. the edges of the universe
c. further back in time.
b. into other universes.
d. further forward in time.
See # 1