THE SOUTHWORTH PLANETARIUM 70 Falmouth Street Portland, Maine 04103 (207) 780-4249 usm.maine.edu/planet 43.6667° N 70.2667° W Founded January 1970 2022-2023: LXV Sunrise: 6:15 a.m. Sunset: 5:32 p.m. Civil twilight begins: 5:46 a.m. Civil twilight ends: 6:01 p.m. Sun's host constellation: Aquarius Moon phase: Waxing gibbous (87% illuminated) Moonrise: 1:32 p.m. Moonset: 5:21 a.m. (03/04/23) Julian date: 2460007.29 "If the dinosaurs went extinct 65 million years ago, then why is Earth only 2021 years old?" - 'Questions that people have actually posted.' THE DAILY ASTRONOMER Friday, March 3, 2023 Quiz # 15: The Jovians And, yes, the quiz has returned, as well. Now that we've all been watching Jupiter and Venus dancing in the east, what better time to offer a quiz about Jovian, or 'Jupiter-like' planets? [image: pluto-gas.jpg] *1. True or false: Jupiter is more massive than all the planets put together?* *2. Which of the gas giants has the greatest number of known moons?* a. Jupiter b. Saturn c. Uranus d. Neptune *3. Which of the gas giant planets contains a "Great Red Spot?"* a. Jupiter b. Saturn c. Uranus d. Neptune *4. Which gas giant planet is rotating "on its side?"* a. Jupiter b. Saturn c. Uranus d. Neptune *5. Which of the gas giant planets require more than 100 Earth years to complete a revolution around the Sun? (Could be more than one.)* a. Jupiter b. Saturn c. Uranus d. Neptune *6. Which of the gas giants did Voyager 2 encounter during its mission?* *(Could be more than one)* a. Jupiter b. Saturn c. Uranus d. Neptune *7. When was Uranus discovered?* a. it has been known since antiquity b. 1678 c. 1718 d. 1781 *8. When was Neptune discovered?* a. it has been known since antiquity b. 1781 c. 1846 d. 1930 *9. Which of the following gas giant planets have rings? (Could be more than one)* a. Jupiter b. Saturn c. Uranus d. Neptune *10. Which of the gas giants planets are named after Greek mythological figures?* a. Jupiter b. Saturn c. Uranus d. Neptune e. none of the above ANSWERS 1. False! If you put all the planets together, you have to include Jupiter! 2. b. Saturn Note that we wrote "known moons," as opposed to "moons," as we have no idea how many moons revolve around these distant worlds. We only know how many have already been found. Saturn has 82 moons! Jupiter is a close second with 79 known moons Uranus: 27 Neptune: 14 We've asked this question before and posted different answers. If we post this question next year, the answer might well change again. 3. a. Jupiter The "Great Red Spot" is a massive storm more than twice Earth's size. This monstrous maelstrom has been raging possibly for centuries. While it has been constantly observed since 1830, Giovanni Cassini recorded a spot in the mid 17th century: possibly the same storm we can see today. 4. c. Uranus Uranus is nearly rotating on its side and keeps one pole toward the Sun. Uranus most likely sustained a devastating impact early in its life. Consequently, the planet was almost knocked over relative to the plane of revolution. 5. d. Neptune The farther a planet is from the Sun, the greater the duration of its orbital period. The three inner gas giant planets require less than a century to complete an orbit around the Sun. Jupiter 11.82 Earth years Saturn 29.46 Earth years Uranus 84.01 Earth years Neptune 164.79 Earth years 6. a. Jupiter b. Saturn c. Uranus d. Neptune Yes, Voyager 2 encountered them all in the following years Jupiter 1979 Saturn 1981 Uranus 1986 Neptune 1989 7. d. 1781 William Herschel discovered Uranus even though he wasn't looking for a planet. 8. c. 1846 Two astronomers, Urbainn Leverrier (French) and John Couch Adams (British), discovered Neptune by studying the perturbations in Uranus which they knew had to have been induced by a hitherto unknown planet. 9. a. Jupiter b. Saturn c. Uranus d. Neptune Saturn is not the only planet to have rings. Granted, its ring system is more extensive and far more magnificent than the rings of the other worlds. Voyager 2 imaged Jupiter's rings in 1979; astronomers James Elliot, Jessica Mink and Edward Dunham discovered Uranus' ring in 1977. Voyager 2 imaged Neptune's rings in 1989. 10. e. none of the above. They are all named for Roman mythological figures To subscribe or unsubscribe from the "Daily Astronomer" http://lists.maine.edu/cgi/wa?A0=DAILY-ASTRONOMER