Stellar and Galactic - Exam 1-2

Stellar and Galactic Astronomy - Exam 1 Name___________________________________ TRUE/FALSE. Write 'T' if the statement is true and 'F' if the statement is false. 1) Constellations are close clusters of stars, all at about the same distance from the Sun. 1) 2) From the South Pole, Polaris would appear directly overhead. 2) 3) There are 3,600 arc seconds in a degree. 3) 4) Kepler found the orbits of planets are ellipses, not circles. 4) 5) The eccentricity of a perfectly circular orbit is 1. 5) 6) Galaxies look the same whether viewed in visible or X - ray wavelengths. 6) 7) A planet (or comet) will speed up as it approaches the Sun. 7) 8) A light - year is a measurement of time. 8) 9) Galileo's observations of sunspots proved the Sun was rotating, like the Earth. 9) SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. 10) The distances to other stars is best measured in ________. 10) 11) The Sun's lowest position in the sky occurs at the ________. 11) 12) The ability of a telescope to separate two closely spaced stars is called ________. 12) 13) According to Newton, the gravity of the ________ is needed to explain planetary orbits. 13) 14) A ________ is a framework of ideas and assumption used to explain some set of observations and make predictions about the real world. 14) 15) We are at ________ in January, when we are closest to the Sun in our elliptical orbit. 15) MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 16) Earth is farthest from the Sun in July and closest to the Sun in January. During which Northern Hemisphere season is Earth moving fastest in its orbit? 16) A) winter B) fall C) summer D) spring 17) During a lunar eclipse, the Moon's phase must be 17) A) third quarter. B) new. C) full. D) first quarter. 1 Marline Corcino Parsec Winter Solstice Resolution Sun Theory Perihelion Winter Full T F T T T F F T T

18) Why is January a cold month in the northern United States? 18) A) There's more snow in January. B) The northern hemisphere is tilted away from the sun. C) Earth is near its farthest point from the sun. D) The northern hemisphere is farther from the sun than the southern hemisphere. 19) What is meant by a hypothesis ? 19) A) a pseudoscientific idea B) a confirmed explanation for a natural phenomenon C) a historical theory that has been proved inaccurate D) a tentative explanation for a phenomenon that can be tested with observations or experiments E) a natural phenomenon that requires explanation 20) What is this a picture of? 20) A) a total lunar eclipse B) a total solar eclipse C) the saros cycle D) a full moon 21) The Ptolemaic model of the universe: 21) A) always kept Mars and Mercury between the Earth and Sun. B) could not account for the stellar parallax observed by Hipparchus. C) explained and predicted the motions of the planets with deferents and epicycles. D) is the basis of our modern cosmology. E) describes the orbits of the planets as being ellipses, not circles. 22) The force of gravity between two objects: 22) A) depends on the density, not the mass of the bodies. B) increases with the masses of the bodies, but decreases with their separations. C) increases with the square of their masses, but decreases with the cube of their periods of orbit about the Sun. D) increases with the masses of the bodies, but decreases with the square of the distances between them. E) depends on the temperature, density, and size of the bodies. 23) Which of the choices below correctly lists things in order from largest to smallest? 23) A) Local Group, Solar System, Milky Way, Universe B) Universe, Local Group, Milky Way, Solar System C) Milky Way, Universe, Solar System, Local Group D) Universe, Milky Way, Local Group, Solar System E) Solar System, Local Group, Universe, Milky Way 2 D D B D C B

27) The time from one new moon to the next is approximately 27) A) one month. B) one week. C) two weeks. D) two months. E) three weeks. 28) How long is the precession cycle? 28) A) 18 years, 11.3 days B) 365.24 days C) 1 day D) 29.5 days E) 26,000 years ESSAY. Write your answer in the space provided or on a separate sheet of paper. 29) How does Kepler's First Law refine the Copernican model greatly? 30) Why do we always see the same face of the Moon? 31) Why did ancient peoples study astronomy? Describe an astronomical achievement of at least three ancient cultures. 4 E A The rotation of the Moon on its axis equals the rotation of the Moon around the Earth, which is why we always see one side facing us and the other facing us at all times. Astronomy has been used by ancient civilizations for a variety of purposes, including navigational, timing, and even farming. 1. Mesopotamia was one of the first civilizations to develop a mathematical system of astronomy to predict astronomical events such as a lunar eclipse. 2. The ancient Egyptians were astronomers, and they used their observations to create an astronomical calendar based on the movement of the stars. 3.The Maya civilization, developed a sophisticated system of astronomy. They used accurate observations of the sun, moon, and planets to create calendar systems that were very precise. Kepler's First Law refines the Copernican model by describing the shape of planetary orbits more accurately. Originally, the solar system was thought to revolve in perfect circles around the Sun, as proposed by the Copernicus. However, according to Kepler’s First Law, the planets do not move in perfect circular orbits around the Sun. Instead, they move in ellipse orbits with the sun at one of two points on the elliptipse.

32) Define astronomical unit and light - year . 5 Astronomical units (AU) are units of measure used in astronomy to refer to distances in the solar system.