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Astronomy Exam
| Question | Answer |
|---|---|
| A planet in retrograde motion... | shifts westward with respect to the stars. |
| Kepler's Third Law | Planets's orbital period is relative to the size of their orbit around the Sun. |
| Galileo used his observations of the changing phases of Venus to demonstrate that... | Venus revolves around the Sun, not Earth. |
| Light years are a unit of... | distance. |
| You write your home address in the order of street, town, state, and so on. Suppose you were writing your cosmic address in a similar manner. What's the correct order? | Earth, Solar System, Milky Way, Local Group |
| Newton's First Law | A body continues to rest or stay in motion unless an unbalanced force acts on it. |
| Newton's Second Law | Force equals mass times acceleration. |
| Newton's Third Law | Equal opposite reaction. |
| Why does something weigh less on the Moon than on the Earth? | The Moon's lower mass creates a lower force of gravity on its surface. |
| What is the correct list of the various parts of the electromagnetic spectrum in the correct order from lowest to highest energy. | Radio waves, infrared, visible, ultraviolet, and gamma rays. |
| In the Orion constellation are stars Rigel, a blue supergiant, and Betelgeuse, a red supergiant. Which star has a greater surface temperature? | Rigel, the blue supergiant. |
| The spectral lines of a star will appear (red shifted/blue shifted) if the star is moving away from the Earth. | red shifted (longer wavelength) |
| The two most important properties of any telescope are... | the light-gathering power and the resolving power. |
| Carl has a 5-inch refracting telescope, and Jim has a 3-inch reflecting telescope. Whose telescope has a higher light-gathering power? | Carl's, because the larger the diameter, the more light to be collected. |
| Using ___________, scientists can use a few smaller telescopes to take images with the same resolution as a much larger telescope. | interferometry |
| The ability of a telescope to show two very close objects separately is called its... | resolving power. |
| What evidence indicates that part of the Earth's interior is liquid? | What evidence indicates that part of the Earth's interior is liquid? |
| What is the best explanation for the Moon's lack of an atmosphere? | The Moon has weak gravity and is close to the Sun. |
| Which of the following objects are primarily rocky with iron cores? | Mercury, Venus, and Earth |
| Which of the following best describes the planets' spins? | Most spin counterclockwise. |
| The Sun is supported against the crushing force of its own gravity by... | gas pressure. |
| The Sun produces its energy from... | the fusion of hydrogen into helium. |
| In what part of the H-R diagram do white dwarfs lie? | Lower center. |
| Which of the following stars is hottest? | An O star. |
| In a sample of nearby stars, about what percentage will lie on the main sequence? | 90% |
| A star's _______ is the most critical factor determining what happens in every phase of a star's life. | mass |
| A star whose mass is 5 times larger than the Sun's and whose luminosity is 100 times larger than the Sun's has a main-sequence lifetime about... | 20 times shorter than the Sun's. |
| As a star like the Sun evolves into a red giant, its core... | contracts and heats. |
| A supernova... | 1. creates elements heavier than iron. 2. disperses metals into the interstellar medium. 3. can outshine the rest of a galaxy. 4. can trigger star formation in a nearby cloud. |
| An H-R diagram of a cluster created from data that included the spectral types of the stars could be used to determine... | the age of the cluster and the distance of the cluster. |
| The Sun will ultimately... | eject its outer layers and leave behind its core as a white dwarf. |
| What has a radius (linear size) closest to that of a neutron star? | A basketball. |
| The Local Group is... | a cluster of galaxies in which the Milky Way is located. |
| An encounter in which a large galaxy absorbs a smaller galaxy is referred to as... | galactic cannibalism. |
| What type of object is believed to be the central source of energy for an active galaxy? | A massive black hole. |
| What type of galaxy has a mix of young and old stars, an abundant amount of gas and dust, ongoing star formation, and a definitive shape? | Spiral galaxies. |
| What type of galaxy has only old stars, little to no gas and dust, and no star formation? | Elliptical galaxies. |
| Astronomers speculate that most galaxies have a massive black hole at their center. What could be the origin of the suspected black hole? | First, a supernova explosion formed a black hole, which in time became more massive by accretion. |
| What is the most likely outcome after the collision between two spiral galaxies? | 1. Enhanced formation of new stars. 2. Formation of a larger galaxy. |
| _____ galaxies contain mostly Population II stars; while _____ galaxies contain both Population I and Population II stars. | Elliptical; spiral |
| Hubble's law implies that the _____ galaxies have larger _____ in their spectral lines. | more distant; red shift |
| _______ galaxies may contain a few million to few trillion solar masses. | Elliptical |
| Stars in globular clusters belong to Population... | II. |
| The Sun lies _______ the disk of our Milky Way Galaxy | about half of the way out in |
| Which of the following may explain the failure to observe population III stars? | 1. Population III stars had their surfaces contaminated by remnants of massive stars. 2. The first stars to be formed in the young Milky Way were very massive and therefore short-lived. |
| The solar system is about 5 billion years old and completes one orbit around the center of the Milky Way in 220 million years. Therefore, we conclude that the solar system has completed a total of about ___ orbits around the galactic center. | 22 |
| The estimated age of the Milky Way galaxy is... | 13 billion years. |
| The Milky Way galaxy contains about _____ stars. Most of these stars are probably _____. | 100 billion; cool dwarfs |
| In general, Population I stars are (older/younger) than Population II stars. | younger |
| In general, Population I stars are _________ and Population II stars are _________. | blue; red |