Universe Study Guide-Key

Test: 10/30/12

  1. Identify and define the four branches of Earth Space Science.

Geology: The study of the origin, processes, and structure of solid Earth.

Astronomy: The study of the universe beyond Earth.

Oceanography: The study of Earth’s oceans. (Covers ¾ of Earth’s surface).

Meteorology: The study of Earth’s atmosphere.

  1. What is cosmology? Study of the origin, structure, and evolution of the universe.
  2. Who proposed that the earth was the center of the universe? Aristotle
  3. Who proposed that the sun was the center of our solar system? Copernicus
  4. Who proved that the sun was the center of our solar system? Galileo
  5. Distinguish between the heliocentric and geocentric models.

Heliocentric models: illustrates that planets rotate around a star in a solar system.

Geocentric Model: illustrates that all universe bodies rotates around the Earth.

  1. What are three things that cosmologists study? how the universe was created, composition of universe bodies, and how the universe is changing.
  2. What is electromagnetic radiation? All the light particles that are produced and emitted by stars via nuclear fusion.
  3. What objects in space emit electromagnetic radiation and which objects reflect it to Earth? Stars produce and emit electromagnetic radiation; all other objects in space reflect light to earth.
  4. Using the electromagnetic radiation hand-out answer these questions:
  1. What are three properties used to classify light particles? Wavelength, frequency, and temperature
  2. Illustrate the difference in wavelength between an infrared light particle and an ultraviolet light particle. Infrared: larger wavelengths

Ultraviolet: smaller wavelengths

  1. What light particles can be seen by a ground telescope? Visible light particles and radio waves
  2. What light particles can only be seen by a space telescope? X-ray, Gamma Rays, Ultraviolet, and some portions of the microwave and infrared regions.
  1. What limits light particles from being collected by ground telescopes? Atmosphere, light pollution created on earth, and size of lens/mirror used in the telescope.
  2. What is a telescope? Collects and focuses light particles from space so it can be magnified and studied.
  3. Distinguish between the refractive telescope and the reflective telescope. (Review telescope hand-out)

Refractive Telescopes: First type of telescope. Uses lenses only to collect, focus and magnify light particles from space. Size of lenses is restricted because can only be supported from the sides, therefore the amount of light that can be collected from space is limited.

Reflective Telescope: Uses mirrors to gather and collect light. Mirrors can be larger than lenses because weight can be supported from the back, making them more valuable to astronomers.

  1. Identify the following components within the universe and know how they are related to one another: galaxies, stars, planets, moons, asteroids, comets.

Galaxies are collection of stars and dust bound together by gravitational force

Stars: collection of solar systems bound together by gravitational force. Each solar system consists of planets, moons, comets, and asteroids revolving around a central star. Moons and asteroids revolve around some planets.

  1. Classify the following as either a space telescope or a space craft that we have used to study aspects of our universe.
  1. James Webb: space telescope
  2. Galileo: space craft
  3. Hubble: space telescope
  4. Voyager I and II: space craft
  5. Curiousity: space craft rover
  6. Cassini-Huygens: space craft
  1. What are two ways in which objects can be measured in space? Astronomical units and speed of light
  2. Who discovered other galaxies and the direction galaxies are moving in our universe? Edwin Hubble
  3. Identify and illustrate the three types of galaxies.(Review galaxy hand-out)
  1. Spiral b. Spherical c. Irregular
  1. What is the difference between a spiral galaxy and a barred spiral galaxy? Spiral galaxy is where the stars are spiraling around each other. Barred spiral galaxy is where there are distinct arms of stars spiraling around each other.
  2. a. What is the expansion theory? The Universe is expanding, due to most Galaxies moving further away from each other. He also noticed that galaxies further away from earth are moving at a faster rate than galaxies closer to earth. Observed by Edwin Hubble.
  1. How does the Doppler Effect prove the expansion theory? Small wavelengths from objects such as a galaxy detected by telescopes proves that the galaxy is moving toward the Milky Way, because the wavelengths emited by the galaxy are being squished together over time. Blue shift

When astronomers detect larger waves from moving objects then it means the objects are moving away from us. Red Shift.

Edwin Hubble noticed that when observing most galaxies around us he observed a red shift being emitted from these galaxies. This means that most galaxies are moving away from us which provides evidence for the expansion theory.

20. Explain the difference between a red shift and a blue shift? Red shift: waves emitted from an object get larger which means the object is moving away from us. Blue shift: waves emitted from an object get smaller over time which means the object is moving toward us.

21. a. What is the Big Bang Theory? A theory of how the universe was created. Astronomers use indirect evidence to propose this big explosion occurred around 13.7 billion years ago.

b. Who proposed the Big Bang Theory? George Lemaitre

c. What is the cosmic egg? Belief that at one time all matter and energy we know of was squeezed together into an incredibly tiny space.

d. What evidence does cosmologist have that supports the Big Bang Theory? Expansion theory by Hubble and the discovery of cosmic background radiation in the 1960s. Cosmic background radiation provides evidence that at one time an explosion did occur. This radiation is relatively spread out amongst the universe,whether there is the presence of a galaxy or not.

22. Approximately how old is our universe? Approximately 13.7 billion years old.

23. How did our solar system form? Gravitational force between dust and gases in space acted upon each other causing them to condense and spiral around one another. The center where most matter was present became extremely hot over time and produce the star of the solar system. All matter around the star eventually condenses and become planets. Due to the density of the star, the planets began to orbit the sun.

25. a. What is dark matter and energy: Dark matter like normal matter seems to be influenced by gravity; however, unlike normal matter it does not emit, absorb, or reflect light. Dark energy which composes most of the universe is what astronomers know the least about. What does seem to be true, is that it opposes gravity, which might explain why the galaxies are moving at increasing speeds away from each other. Is it the dark energy that is responsible for this observation?

b. Why is dark matter and energy important to study? Because it composes most of the universe: normal matter: 4%, dark matter: 21% and dark energy: 75%

26. What are three ways in which astronomers classify stars?

a. Color of Stars: amount of energy emitted by star (temperature)

b. Luminosity of Stars: related to magnitude of star’s brightness

c. Size of Stars

27. What is luminosity? Brightness of a star.

28. a. What is the difference between absolute and apparent magnitude?

Absolute magnitude: True brightness of a star if it was a specific distance (33 light years) from us. Apparent Magnitude: Brightness of star from earth.

b. Is a blue star or a red star hotter? A blue star is hotter.

29. What two elements make-up most stars? Hydrogen and Helium

30. Identify the life cycle terms/stages below of a star:

Stage 1: Nebula : A cloud of dust and gases that will eventually make-up a star.

The gravitational force between the dust and gases begin to shrink and spin around one another.

Protostar: As the gravitational force continues to shrink and spin the gas and dust particles around one another, a hot dense region forms in the middle of the nebula. This hot dense region will continue to get smaller and hotter and will eventually become the star.

Stage 2: Main Sequence Star: When this dense region is hot enough (10 million oC) nuclear fusion can occur between the hydrogen atoms. In nuclear fusion, the hydrogen atoms’ nuclei collide and become a Helium atom. Also immense amount of energy is created. This immense amount of energy stabilizes the star by counter balancing the gravitational forces that are trying to crush the star. gravitational forces = nuclear fusion forces

  • Longest stage of a star’s life cycle.
  • The size of a star is determined. : Average star or Massive star

Stage 3: When Hydrogen atoms are gone, nuclear fusion cannot consistently occur, therefore gravitational force > nuclear fusion. The star becomes unstable. The star then begins to fuse Helium atoms together to create carbon or oxygen. The outer gases around the star begins to expand (10 to 100x its size) and cool.

Average Stars become Red Giants

Massive stars become Red SuperGiant

Stage 4: This is when helium atoms are gone, therefore nuclear fusion cannot occur anymore. This is the death stage of a star. With no more nuclear fuel, nuclear fusion cannot occur anymore, so over time gravitational force continues to get stronger and stronger.

Red Giant becomes a White Dwarf (light particles are emitted but not created anymore from nuclear fusion --> Black Dwarf (not emitting anymore light particles)

Red Super Giant becomes a Supernova (huge explosion occurs when gravitational forces are the only forces acting on the star causing it to crush into an extremely small space ---> Neutron Star (after explosion most matter is spilled into the universe, the matter left consists of neutrons (subatomic particles of matter) ----> Black Hole ( this rarely occurs, but if the neutron star is dense enough it might collapse in on itself creating a black hole)

31. Determine which life cycle stage of star this belongs to:

a. Our sun is in this stage? Stage 2: Main Sequence

b. Where the gravitational force starts to contract and condenses a cloud of dust and gases. Stage 1: Nebula/protostar

c. Stage where nuclear fusion occurs with Helium atoms. Stage 3: Red Giant or Red Super Giant

d. Stage where nuclear fusion occurs with Hydrogen atoms. Stage2: Main Sequence

e. Stage where nuclear fusion stops because the nuclear fuel is used up. Stage 4: Death of a star

f. Stage where the gravitational force = nuclear fusion forces: Stage 2: Main Sequence; stage 3: Red Giant/Red Supergiant

g. Stage where the gravitational force> nuclear fusion forces. Beginning and end of stage 3 and stage 4

h. Stage where the star is dead. Stage 4 (white dwarf or supernova)

i. Stage where a star might be so dense that it collapses in on itself. Stage 4(neutron- black hole)

j. The longest stage of a star’s life. Stage 2: Main Sequence

32. Make sure you can interpret the H-R diagram that you created and understand the questions you answered from that assignment.

33. From the H-R diagram you created answer these following questions:

a. Identify a star that is older than our sun. How do you know?

b. Identify a star that is hotter or cooler than our sun.

34. Identify the inner and outer planets. Inner: Mercury, Venus, Earth, and Mars

Outer: Jupiter, Saturn, Uranus, and Neptune

35. Inner planets are called the terrestrial planets because they obtained most of the solid debris around the sun. These planets are primarily consist of solid rock with a metallic core. Outer planets are composed primarily of gases, therefore they have heavy, thick atmospheres.

36. A meteor is a small fragment of rock that orbits the sun. If comes close to a planet, the planet’s gravitational force will pull it into its atmosphere. As the meteor falls through the planet’s atmosphere it burns up (what we call a shooting star), and if any makes it to the planet’s surface it is called a meteorite. An asteroid is a rock this is large then a meteor but smaller than a planet. I also orbits the sun. There is a cluster of asteroids that separate the inner and outer planets. It is called the asteroid belt.

37. A shooting star is a meteor that is falling through a planet’s atmosphere. The friction created during the fall causes it to burn up.

38. The Kuiper’s Belt is beyond Neptune. It consists of smaller planets called dwarfs. The most popular dwarf planet is Pluto.

39. The asteroid belt separates the inner and outer planets. It is located between Mars and Jupiter.

*Power points are on my webpage under the folder labeled: Universe *

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