PhysicsName: ______
Space Test ExplanationsFinal Exam Practice Part IAnswer on a separate sheet of paper.
#1-4 In its earliest form, our solar system was huge, cold, and slowly-turning. It had no particular shape. Over time, our solar system shrank, heated up, began to spin faster, and became disk-shaped. For the questions below, give the immediate causes for each event.
1. What caused it to shrink? a. heatb. electrostatic forcec. momentumd. gravityGravity pulled it together.
2. What caused it to heat up? a. frictionb. compression (pulling together) c. momentumd. sunlightAs the nebula pulled together, pressure (compression) caused it to heat up.
3. What caused it to spin faster?a. heatb. compression (pulling together) c. electrostatic forced. nuclear fusion
The nebula spun faster because it contracted (pulled together)
4. What caused its shape to become a disk?a. heat b. electrostatic force c. momentumd. gravityThe momentum of the flying particles in the nebula pulled them outward.
5. Today’s planets formed from dust and gasses that clumped together. What caused this clumping into actual planets?
Gravity
a. electrostatic forces (+ and -)b. Nuclear Fusionc. Gravityd. Friction
6. The inner planets of our solar system are rocky, while the outer planets are “gas giants.” Why are the inner and outer planets different?
a. momentum pulled the inner planets’ gas outward, away from the sun
b. the outer planets have less momentum, so they did not cause their gases to fly away
c. the outer planets’ strong gravity pulled in more gases
d. the area near the sun was too hot for gases to survive The sun “burned away” the gases that were near the sun. The inner planets are close to the sun, so there was not much gas available for them to become gas giants.
7. What is Nuclear Fusion?
a. Nuclear fusion is tthe combination of existing atoms to create entirely new atoms of a new element.
b. the breaking apart of atoms, as in a nuclear bomb
c. the combination of several hydrogen atoms to make one bigger hydrogen atom
d. the combination of different types of atoms to create a chemical compound
8. How does nuclear fusion produce energy?
a. Fusing atoms rub together, producing energy
b. Gravity accelerates atoms together as they fuse, causing them to move very fast.
c.When atoms fuse, the new atoms that are created have less mass than the atoms that fused. This means mass is “lost.” That “lost” mass is converted to energy. Fusion produces atoms with less mass than the original atoms that fused
d. Fusion causes explosions as the atoms’ electron shells are broken.
9. Nuclear fusion can only occur in the center of the solar system. Why is that?
a. That’s the oldest part.
b. Fusion requires hot, fast atoms
c. There are no “frozen gases” to get in the way.
d. The atoms there have the least momentum, so they can line up with one another.In order to fuse, atomic nuclei have to hit each other with great force. This can only happen if the atoms are moving very fast. Hot atoms move the fastest, and the hottest part of the solar system was the center (where there was the most pressure).
10. What would happen to the orbit of a planet if it suddenly started orbiting faster? The planet would have more momentum, and this momentum would “pull” the planet farther from the sun.
a. The planet would orbit farther from the sun
b. The planet would orbit closer to the sun
c. The planet would get hotter
d. Gases would be stripped from the planet by air resistance
11. As a new star isborn, what type of atoms first begin to fuse?
a. xenon b. hydrogen c. nitrogend. oxygene. heliumHydrogen
12. Which type of new atoms are created when these first atoms fuse?
a. xenon b. hydrogen c. nitrogend. oxygene. heliumHelium
13. As stars get older, they often expand to become red giants. Why do stars eWhy are some stars red giants? xpand in this way, and why do they turn red?
a. They have more mass than average stars.
b. Nuclear fusion has created a lot of helium in their cores.
c. They are closer to us than other stars.
d. Red giants contain different types of elements that radiate mostly red light.
e. Red giants are newly-created stars that have not yet cooled down.In these stars, a lot of hydrogen has already fused. This fusion creates helium, which is more dense than hydrogen. The helium sinks to the star’s core and pushes the hydrogen outward. This outward push causes the star to expand (become giant). As the fusing hydrogen moves away from the star’s core, it enters an area of lower pressure. This causes hydrogen fusion to slow down, which produces less energy. This fusing hydrogen cools off, so it turns red (the coolest color).
14. How do we know what elements are inside stars? We use spectroscopes to examine the wavelengths of light coming from those stars.
a. We have sent space probes to collect material from stars.
b. We analyze stars’ speeds of rotation around other massive objects.
c. We analyze the wavelengths of light coming from stars.
d. We measure stars’ sizes using telescopes.
15. Which of the following ranksPut these star colors in order from hottest (on the left) to coolest (on the right)? Blue, White, Yellow, Orange, Red Colors: yellow, red, blue, white, orange
a. Red, orange, yellow, white, blue
b. Yellow, White, Blue, Red, Orange
c. Orange, Red, Yellow, Blue, White
d. White, Blue, Yellow, Orange, Red
e. Blue, White, Yellow, Orange, Red
16. A massive star (25 times the size of our sun) is like an onion. It has layers of various elements. Why do those layers form?
a. The heavy elements produced by nuclear fusion sink to the center.
b. The layers represent material of different ages, inner layers were formed first.
c. The different layers are asteroid and meteorites that collided with the stars.
d. The different layers are different stars that combine as they are pulled together by gravity.The outer layers fuse, creating heavier elements. Those heavier elements sink to the star’s center, where they themselves fuse to create even heavier elements. Then those new elements sink to the star’s center. This is repeated until there are many layers whose densities increase as the star’s center is approached.
17. Why can’t a star like our sun ever become a black hole?
a. It’s too small.
b. It’s too close to the center of the galaxy.
c. It’s too hot.
d. It has too much hydrogen, and not enough rock and metal
e. It’s too cold.In order to form a black hole, a star must have tremendous gravity. Our sun does not have enough mass. A dead star must have at least three times the mass of the sun in order to become a black hole.
18. Why isn’t our sun blue? Our sun doesn’t have enough mass. Blue stars are the hottest stars, and a hot star needs a lot of pressure. In order for there to be a lot of pressure, a star needs a lot of mass. Our sun doesn’t have that much mass.
a. It’s too big
b. It’s too old
c. It’s too young
d. It’s too small
e. It’s too slow
19. Which of the waves on the right has the most energyDraw a high energy wave and a low energy wave. Label them? Letter b, on the right, shows a high energy wave. Letter e shows a low energy wave.
20. Which of the following type ofthe waves on the right has the longest wavelength? (see diagram)
a. infraredb. x-ray
c. UVd. Radio
e. Visible lightWavelength is the distance from one “hump” (really a crest) to the next. In the diagram, Radio waves have the most space between crests.
21. At some point, our sun will shrink and become a white dwarf. Why will shrinking cause the sun to turn white. Why?Shrinking will compress the sun. Compression will heat it up. Heating will cause it to turn from red to white.
a. It will heat up due to compression
b. It will cool off and shrink.
c. It will be mostly helium ash
d. It will have all types of atoms, so their colors will combine, making white light
22.Where Our solar system formed from a Nebula. Where do Cosmologists think our solar systemthat nebula came from (just before it was a nebula – not way back at the moment of the Big Bang) (just before it turned into a sun and planets)? Cosmologists think our nebula came from material that was blasted into space during a supernovae (the explosive death of a massive star).?
a. A supernovab. The Big Bangc. A neutron stard. A black hole
23. Protons and electrons fuse in a:
a. red giantb. newly-forming nebulac. sun’s centerd. neutron star neutron star ______.
24. The shape of a black hole is:
a. a sphereb. a funnelc. too small to have a shaped. a double-ended funnele. flat a sphere a ______.
25. The place where all of the mass of a black hole is located:
a. event horizonb. singularityc. nucleusd. coree. supernova the singularity is the _____.
26. When a massive, dying star blows itself apart, if the remaining mass is less than three times the mass of the sun, the leftover material will form a:
a. neutron starb. white dwarfc. black dwarfe. black holed. supernovaneutron star ______.
True/False: a=true; b=false
27.Our sun can never become a black hole because it does not have enough mass.
28. Cosmologists think the the material in our bodies was once part of a massive star. Explain how it went from a star to our bodies. They think the star exploded in a supernova. The supernova blasted material out into the universe. Some of this material pulled back together to form our solar system. Some of those bits of the solar system ended up in our bodies.
29. Which of the following is evidence for theDescribe two pieces of evidence for Big Bang theory?1) all distant galaxies are moving away from us 2) There is microwave radiation (energy) spread throughout the universe. Cosmologists think this is “heat” left over from the Big Bang.
a. Cosmologists have used carbon dating to determine the ages of the earth and the moon.
b. Most objects in space are spinning rapidly.
c. Using technology, we can still hear slight echoes from the original big bang.
d. The light coming from distant stars has stretched-out wavelengths.
30. Which of the following doC cosmologists believe to be true about the Universehave observed that distant galaxies are moving away from us, but they say that these galaxies are not moving through space. How can this be?
a. All galaxies, including ours, are moving outward through space away from the location of the Big Bang.
b.Galaxies are not moving through space; space itself is actually growing.
c. Galaxies are now being pulled back together by gravity, so that some day there will be “Big Crunch.”
d. Before the Big Bang occurred, space was cold and dark. Cosmologists tell us that the space between the galaxies is expanding. The galaxies are not moving through space.
31. How doDescribe one way in which scientists estimate the universe’s age (roughly 14 billion years)? They measure the distance to a distant galaxy. Then they measure the velocity at which that galaxy is moving away from us. Finally, they use the formula t=d/v to calculate the age of the universe.
a. By using radioactivity to determine the ages of rocks and meteorites
b. By measuring the decrease in the temperature of space.
c. By measuring the speeds of galaxies and our distance to those galaxies.
d. By measuring how fast the universe is beginning to come back together.
e. By looking at the colors of the oldest stars.
3231. Nobody knows how big the universe is. We don’t even know whether or not it goes on forever. Plus, there’s no way that we can ever find out how big it is. Explain why we can never know the universe’s size.
The universe isn’t old enough. Since the universe is only about 14billion years old, light from objects farther than about 14 billion light years has not had enough time to reach us. a. The universe’s size keeps changing.
b. The idea of “distance” makes no sense in outer space.
c. Our telescopes are not powerful enough to see the farthest objects.
d. The universe is not old enough for us to determine its size.
3332. At which position on the right will people on the Earth see the other star undergo the greatest blue shift? The answer is C, because the earth is moving toward the star at position C. If this is on the test, the diagram will be different.
3433. At which position on the right will people on the Earth see the other star undergo the greatest red shift? The answer is A, because the earth is moving away from the star at position A. If this is on the test, the diagram will be different.
3534. You’re a bat, and you’re flying around in search of insects. You send out a screeching sound. Your screech echoes off of a mosquito that is coming toward you. Compared to the sound you made, the screech that you hear is:how does the echo sound different? higher in pitch. When things move toward you, their sounds are higher pitched. When they move away, their sounds are lower pitched.
a. louderb. stronger (greater force)c. higher in pitchd. lower in pitch
3635. You already know that velocityv=d/t, so t=d/v. Ned the cosmologist measures the distance of galaxy D at 9 billion light years away from earth. He measures the velocity at which Galaxy D is moving away from us, and he gets 0.5c. According to Ned’s measurements, what is the age of the universe? t=d/v, so age of universe = 9 billion light years / 0.5c = 18 billion years.
a. 18 billion yearsb. 4.5 billion yearsc. 9.5 billion years
d. 14 billion yearse. 14 billion light years
3736.Assuming that all of the waves on the right came from the same light source out in space, in which case was the light source moving most rapidly away from the earth?
T/F: a=true; b=false e, because the wavelengths of e have been lengthened (“stretched out”). This is what happens to waves emitted by an object that is moving away from us.
3837. “Cosmologists tell us that nothing at all happened in the billions of years before the Big Bang.” Why is that last statement false? Cosmologists say that time did not exist before the Big Bang; there was no “before.”
3938. “If I am 37 years old, then my age in light years is much greater than 37.” Why is that last statement false?What is wrong with that statement? A light year is a measure of distance (the distance that light travels in one year) not time. You can measure distances in light years, but you can’t measure ages in light years.
4039. According to cosmologists, the “cosmic singularity” contained allWhat was the “cosmic singularity?” The infinitely small point where all of the universe’s mass was located at the moment of the Big Bang. of the mass that is now in the universe.
Bonus: If we can’t see a black hole, how can we ever know that one is there?