THE SOUTHWORTH PLANETARIUM 207-780-4249 www.usm.maine.edu/planet <http://www.google.com/url?q=http%3A%2F%2Fwww.usm.maine.edu%2Fplanet&sa=D&sntz=1&usg=AFQjCNHulkHuLP13bOG2PkNrPazsGWFs2A> 70 Falmouth Street Portland, Maine 04103 43.6667° N 70.2667° W Altitude: 10 feet below sea level Founded January 1970 Julian Date: 2459205.16 2020-2021: LXIII THE DAILY ASTRONOMER Monday, December 21, 2020 Remote Planetarium 136: Final Test II Well, first things first: Happy Winter! Yes, today is the December solstice. The first day of winter in the Northern Hemisphere. The first day of summer for the Southern Hemisphere. Even though the daylight duration will start to increase, the sunrise time will continue to increase until early January. Conversely, the earliest sunset occurred about two weeks ago. As winter begins, the Remote Planetarium ends. We hope you've enjoyed the course! A brand new remote course begins on January 4th. Good luck! *21. One of the lunar eclipses in Saros Cycle 149 will occur on August 17, 2092. When will the following Saros 149 lunar eclipse happen?* a. August 17, 2099 b. August 23, 2101 c. August 26, 2105 d. August 29, 2110 *22. **Kepler''s Third Law of Planetary Motion states that the square of a planet's period is proportional to ____________________* a. the square of its mass b. the square of its average distance from Earth c. the cube of its semi major axis (average distance from the Sun) d. its momentum *23. **Why are Type Ia Supernovae useful to determine the distances to remote celestial objects?* a. they are always close b. Type Ia supernovae are of equal brightness, in theory c. they only appear in nearby galaxies d. none of the above. Type Ia Supernovae are not actually useful for distance determination. *24. **If a star's parallax angle is 0.1", how far away is it?* a. 1 parsec b. 10 parsecs c. 100 parsecs d. 1000 parsecs [image: download.jpg] *25. The image above shows an idealized light curve for a transiting planet. What does the depth of the lower part of the curve reveal?* a. the planet's period b. the planet's size c. the planet's temperature d. the planet's chemical composition *26. **How can astronomers determine the chemical constituents of an exo-planet's atmosphere?* a. they can't. They can make an educated guess about the chemicals based on the planet's mass. b. the chemicals present in the parent star are always present in the exo-planet's atmosphere c. the star's light passes through the atmosphere, the gases of which absorb light at different wavelengths. This spectrum is used to identify the gases present in the atmosphere. d. none of the above. *27*. *What value can one estimate through use of the Drake Equation?* a. the number of advanced civilizations in the Milky Way Galaxy b. the number of aliens in the solar system c. the ratio of stars with aliens to those without d. the percentage of planets capable of harboring life *28. ** Approximately how quickly is our solar system traveling through the galaxy?* a. 55 miles per hour b. 1,000 miles per minute c. 143 miles per second d. the speed of light *29. **The Sun completes one orbit around the galaxy every __________ years, approximately.* a. 3000 b. 19 million c. 104 million d. 225 million *30*. *Fritz Zwicky first wrote about dark matter in ______ after having observed the _______________________.* a. 1933; Coma Cluster of Galaxies b. 1954; Andromeda Galaxy c. 1967; Large Magellanic Cloud d. 1981; Perseus Supercluster *31. **Approximately _______% of stars in the Milky Way are main sequence stars.* a. 20 b. 40 c. 65 d. 92.5 *32.* *What is "dark energy?"* a. gravitational potential energy b. the energy that powers black holes c. the force believed to be responsible for the acceleration of the cosmic expansion d. none of the above *33. **Approximately _________________ years after the Big Bang, the first stars formed.* a. 100,000 b. 20 million c. 200 million d. 560 million 34. * Why don't astronomers think that they have an accurate count of all the galaxies within the Local Group?* a. some of the galaxies consist only of dark matter and aren't visible b. some of the galaxies are blocked from view by the Milky Way Galaxy c. the Local Group galaxies they observe are so far away that they have probably dissipated by now. d. none of the above. *35. **The Andromeda Galaxy is also known as M31. What does the M signify?* a. the galaxy type. M stands for "Major Spiral" b. that it is part of the Messier catalog c. its distance. M stands for "megaparsec." d. the year of its discovery. This scheme combines Roman and Arabic numerals. M31 indicates that observations of this galaxy were first recorded in 1031. *36. ** The fundamental postulate of Special Relativity states that the "Speed of light is ___________________"* a. equal to the cube root of the Planck constant divided by pi b. equal to 186,290 miles per second c. constant in all inertial reference frames d. not able to be precisely measured. *37.* *Danish astronomer Ole Roemer first determined that light traveled at a finite speed by observing ______________.* a. a partial solar eclipse b. Jupiter's Galilean moons c. the tilt of Saturn's rings d. a meteor storm *38. One twin flies on a rocketship moving at 90% light speed. Another remains on Earth. If the flying twin travels to Alpha Centauri and then returns to Earth, he will be ____________ than his Earth-bound twin.* a. younger b. older c. much heavier d. much lighter *39*. *If the Sun just disappeared, Earth would stop being influenced by its gravity __________.* a. instantly. b. within three seconds c. in 8.4 minutes d. in a year. *40. ** Why is warp speed not possible?* a. no vessel can travel at light speed because at that speed the vessel's mass would become infinite b. no vessel can travel at light speed because the speed would actually travel backward through time c. no vessel can travel at light speed because such motion would violate the traffic laws in the Delta Quadrant d. none of the above 41. *The Universe contains approximately _____________ Superclusters.* a. 100 b. 10,000 c. 1,000,000 d. 10,000,000 *42. **Observations of _______________ variables enable astronomers to measure the distances to nearby galaxies.* a. Algol b. Cepheid c. T-Tauri d. none of the above *43. **The phenomenon that causes distant light to be bent and focused around foreground objects is known as _______________________* a. red shift b. gravitational lensing c. blue shift d. the Sunyaey-Zel'dovich effect *44*. *What discovery in 1964 convinced most scientists that the Big Bang Theory was correct?* a. Penzias and Wilson's detection of the Cosmic Microwave Background Radiation b. Watson and Crick's discovery of the DNA molecule c. Kepler and Brahe's discovery of the Harmonic Law d. Penzias and Wilson's discovery of pulsars 45. *Which one is not a twilight phase?* a. civil b. nautical c. diurnal d. astronomical ANSWERS *21. One of the lunar eclipses in Saros Cycle 149 will occur on August 17, 2092. When will the following Saros 149 lunar eclipse happen? * d. August 29, 2110 Eclipses within the same Saros cycle are separated by 18 years 11 days and 8 hours. *22. **Kepler''s Third Law of Planetary Motion states that the square of a planet's period is proportional to ____________________* c. the cube of its semi major axis (average distance from the Sun) This relation is also known as the "harmonic law." The square of a planet's orbital period (in years) equals the cube of its semi major axis (mean distance) in Earth years. *23*. *Why are Type Ia supernovae useful to determine the distances to remote celestial objects?* b. Type Ia supernovae are of equal brightness, in theory Because Type Ia supernovae occur when the white dwarf's mass exceeds 1.44 solar masses, each one should release the same amount of energy and be of equal brightness. *24*. *If a star's parallax angle is 0.1", how far away is it?* b. 10 parsecs To determine a star's distance, one must divide the number 1 by the parallax angle expressed in arc-seconds. 1/0.1 = 10 parsecs. *25. **The image above shows an idealized light curve for a transiting planet. What does the depth of the lower part of the curve reveal?* b. the planet's size The larger the planet, the greater the area it blocks and so the deeper the curve. *26. **How can astronomers determine the chemical constituents of an exo-planet's atmosphere?* c. the star's light passes through the atmosphere, the gases of which absorb light at different wavelengths. This spectrum is used to identify the gases present in the atmosphere. Each molecule absorbs light at specific wavelengths. By examining the absorption lines, astronomers can identify the gases present in an exo-planet's atmosphere. 27. *What value can one estimate through use of the Drake Equation?* a. the number of advanced civilizations in the Milky Way Galaxy The Drake Equation combines our knowledge of stars and planets with speculations about life's resilience. *28.* *Approximately how quickly is our solar system traveling through the galaxy?* c. 143 miles per second That rate is certainly rapid by terrestrial standards. The solar system could travel from Portland (ME) to Boston in less than one second. (Of course, that sentence doesn't make much sense!) Yet, by galactic standards, the solar system is moving at a somewhat lethargic pace. *29.* *The Sun completes one orbit around the galaxy every __________ years, approximately.* d. 225 million The period of time the Sun requires to complete one orbit is called a "galactic year." During its lifetime, the Sun has completed more than twenty circuits around the Milky Way. Incidentally, the entire Mesozoic Era, the time period when the non-avian dinosaurs existed, was about 50 million years shorter than a galactic year. *30**. Fritz Zwicky first wrote about dark matter in ______ after having observed the _______________________.* a. 1933; Coma Cluster of Galaxies His work was ignored for about half a century. Now, dark matter is widely accepted in the astronomical community. *31.**Approximately _______% of stars in the Milky Way are main sequence stars.* d. 92.5 Main sequence stars are the type V dwarf stars that are currently fusing hydrogen into helium. The Sun is a main sequence star and will continue to be a main sequence star for the next five billion years. *32.* *What is "dark energy?"* c. the force believed to be responsible for the acceleration of the cosmic expansion Cosmologists have determined that the cosmic expansion is accelerating with time, as opposed to being impeded, as was one believed. They ascribe this acceleration to "dark energy," a force that remains mysterious. In this instance the "dark" refers to our ignorance of its nature. *33. **Approximately _________________ years after the Big Bang, the first stars formed.* d. 560 million The first generation of stars formed about half a billion years after the Big Bang. By that time, the Universe consisted primarily of hydrogen and helium. From this material stars coalesced and through a series of complex fusion reactions created heavier elements. *34. **Why don't astronomers think that they have an accurate count of all the galaxies within the Local Group?* b. some of the galaxies are blocked from view by the Milky Way Galaxy. We remember that we live along the galaxy's "Orion Spur." Consequently, we cannot see many regions along the other side of the galaxy due to the intervening gas and dust. Astronomers refer to this occluded region as the "Zone of Avoidance." Any galaxies around this zone will also not be visible to us. *35.* *The Andromeda Galaxy is also known as M31. What does the M signify?* b. it is part of the Messier catalog French astronomer Charles Messier (1730-1817) compiled a catalog of celestial objects that resembled comets when observed telescopically. The Andromeda Galaxy (or the "Andromeda Nebula" as he called it) was the thirty-first entry in that catalog. *36.* *The fundamental postulate of Special Relativity states that the "Speed of light is ___________________"* c. constant in all inertial reference frames A remarkable statement. If you're in a rocket ship moving at 80% the speed of light and you measure a light beam's speed, it will appear to be moving at light speed if you are moving toward it or away from it. No matter how fast an observer travels, the speed of a light beam will remain constant. Consequently, light speed is denoted by the letter "c." *37. **Danish astronomer Ole Roemer first determined that light traveled at a finite speed by observing ______________.* b. Jupiter's Galilean moons Roemer realized, for instance, that the timing between successive eclipses of Io was shorter when Jupiter was closer to Earth than it was farther away, He ascribed this difference to the finite speed of light, as the reflected light of Io needed a longer time to travel to Earth when it was farther away. *38.* *One twin flies on a rocketship moving at 90% light speed. Another remains on Earth. If the flying twin travels to Alpha Centauri and then returns to Earth, he will be ____________ than his Earth-bound twin.* a. younger A traveler moving at such a high velocity will experience less time than a "stationary" observer. (Being on a revolving and rotating planet, the Earth bound twin will not be truly stationary.) The rocket traveler will actually be younger than his twin. *39. ** If the Sun just disappeared, Earth would stop being influenced by its gravity __________.* c. in 8.4 minutes Gravity waves travel at light speed. So, if the Sun were to just "go away," Earth would still feel its gravity for the next 8.4 minutes because the Sun is 8.4 light minutes from Earth. 40. *Why is warp speed not possible?* a. no vessel can travel at light speed because at that speed, the vessel's mass would become infinite The faster a ship moves, the greater its inertial mass becomes. At light speed, a vessel's mass would become infinite. Something infinitely massive would require an infinite amount of energy to sustain its motion. *41. **The Universe contains approximately _____________ Superclusters.* d. 10,000,000 Our vast Virgo Supercluster is certainly not the only one. *42*. *Observations of _______________ variables enable astronomers to measure the distances to nearby galaxies.* b. Cepheid A Cepheid variable's luminosity determines its variability period. The longer the period, the more luminous the variable star. By observing a Cepheid's variability period, an astronomer can determine its intrinsic brightness (absolute magnitude). The Cepheid's distance is then determined by comparing its absolute magnitude with its apparent magnitude. *43. **The phenomenon that causes distant light to be bent and focused around foreground objects is known as _______________________* b. gravitational lensing The distant light is bent around the foreground object's space-time curvature. The amount of material determines the extent of this lensing effect. The mass of galaxy clusters can be approximated by analysis of this lensing. *44. **What discovery in 1964 convinced most scientists that the Big Bang Theory was correct?* a. Penzias and Wilson's detection of the Cosmic Microwave Background Radiation Physicist Arno Allan Penzias and radio astronomer Robert Woodrow Wilson discovered the pervasive "static hiss" indicative of the Cosmic Microwave Background Radiation through their radio antennae. *45.* *Which one is not a twilight phase?* c. diurnal We recognize three distinct twilight phases: *Civil *(when the Sun is between 0 to 6 degrees below the horizon) ends at 4:43 p.m *Nautical *(when the Sun is between 6 - 12 degrees below the horizon) ends at 5:18 p.m. *Astronomical *(when the Sun is between 12 - 18 degrees below the horizon. ends at 5:52 p.m.