THE SOUTHWORTH PLANETARIUM
207-780-4249 www.usm.maine.edu/planet
70 Falmouth Street Portland, Maine 04103
43.6667° N 70.2667° W
Founded January 1970
Julian date: 2457634.16
"Out in the wild black yonder."
As this is the first quiz of the new DA School Year, we wanted to announce a couple quiz changes, as well. First, we'll elaborate more on the answers. Secondly, we'll re-introduce the "ratings system," which assigns desigations to players based on the quiz performance. We don't mind including this feature as well, although we will be quite careful not to insult anyone. Oh, and, of course, there are the Roman numerals we'll assign to the quizzes through the school year to make us seem far more important than we actually are.
THE DAILY ASTRONOMER
Friday, September 2, 2016
Quiz I: All Things Bright and Astronomical
From lunar phases and meteors to galactic superclusters and the cosmic microwave background radiation, astronomy is just about anywhere, everywhere, and in all places in between. This first quiz of the 2016-17 school year focuses squarely and cubely on all things astronomical. As we've already established, that covers so much territory that even a 1000 question quiz would scarcely scratch the surface. Don't panic. It will be awhile before we entertain you with a quiz like that.
1. What is a "blue moon?"
a. the name of the full moon when it is at the zenith (point directly overhead.)
b. the name givent to January's full moon
c. the second full moon in a given calendar month
d. a name often given to Venus as it rises
2. Earth has a magnetic north and magnetic south pole. Which ONE of the following statements about them is not correct?
a. Geographically, they are not diametically opposed (180 degrees apart).
b. Both poles drift
c. The magnetic north pole is currently aligned precisely with the geographic north pole
d. The Aurora Borealis ("Northern Lights") and Aurora Australis ("Southern Lights") are centered around these poles.
3. If you are looking at the "gegenshein", what are you seeing?
a. an image of the false sun appearing in the night sky
b. the aurora borealis
c. the dark patches within the Milky Way
d. an unusually bright comet
4. Which planet appears the brightest in the night sky from our perspective?
a. Mercury
b. Venus
c. Mars
d. Jupiter
e. Saturn
5. Around which planet will one find the Galilean Moons?
a. Jupiter
b. Saturn
c. Uranus
d. Neptune
6. In September, one would expect to find Orion's Belt in the __________________ part of the sky around ________________________.
a. eastern; 8:00 p.m.
b. eastern; 4:00 a.m.
c. southern; midnight
d. western; 10:00 p.m.
7. Which ONE of the following cannot be created by a supernovae?
a. black holes
b. white dwarfs
c. neutron stars
d. nebulae
8. What is meant by a star's "luminosity?"
a. the amount of energy it emits every second
b. its temperature
c. its distance from Earth
d. its chemical composition
9. Galactic and globular clusters are quite different. Which of the following statements about their differences isn't true?
a. Galactic clusters are much smaller than globular clusters
b. Galactic clusters are much younger than globular clusters
c. Galactic clusters have a lot more stars than globular clusters
d. Globular clusters populate the halo surrounding the galactic nucleus, whereas galactic clusters are generally found within the outer disc of the galaxy
10. What is the name of the cluster of more than 54 galaxies to which the Milky Way Galaxy belongs?
a. The Local Group
b. The Virgo Coven
c. The Capricornus Consortium
d. The Sagittarius Assembly
ANSWERS
1. c. the second full moon in a given calendar month
The period of time separating two successive full moons -called its "synodic period"- equals 29.53 days. Every month, save February, is longer than the lunar synodic period. Therefore, one can have a blue moon in any month except February. A 'blue moon' is also defined as the fourth full moon in one season. The second definition is considered the original, while the first definition arose later.
2. c. The magnetic north pole is currently aligned precisely with the geographic north pole
The north magnetic pole is not aligned with the north geographic pole. Presently, the north magnetic pole is centered on 86o 24' N 166o 18' W. The pole drifts by 55 - 60 kilometers per year. The south magnetic pole is presently positioned at 64O 17' S 136O 35' E Earth's magnetic field is not symmetrical, so these poles are not 180 degrees apart.
3. a. an image of the false sun appearing in the night sky
The word "gegenshein" is a German term meaning "counter shine." It sometimes appears in the night sky when dust particles along the ecliptic (the Sun's apparent annual path) reflect light fron the Sun, which will be 180o away from this gegenshein. The best time to view this effect is around Oct/Nov and between midnight and 1:00 a.m. Even at these ideal times, the gegenshein is still not an easy sight to behold. It is a subtle effect, much like the zodiacal glow, which is also caused when dust reflects sunlight along the ecliptic.
Can you see the "gegenshein?" Look for the elliptical light patch against the starfield.
(Image by ESO/Stéphane Guisard )
4. b. Venus
The moon is the only night sky object brighter than Venus. There are four factors determining a planet's brightness. Its distance from the Sun, its distance from Earth, its size and its albedo, which measures the ratio of light reflected to light received. Venus is closer to the Sun. Venus is also one of the closest planets to Earth (Mars is the other). Unlike Mars, Venus is only slightly smaller than Earth. Also, its albedo is 0.65, meaning that it reflects 65% of all sunlight back into space. Jupiter is the second brightest planet. However, even if Jupiter were at its maximum brightness at the same that that Venus were at its minimum brightness, Venus would still be more than 2.5 times brighter than Jupiter!
5. a. Jupiter
The Galilean moons are Io, Europa, Ganymede and Callisto. They are so named because Italian astronomer Galileo Galilei (1564-1642) discovered these Jovian satellites in 1610.
6. b. eastern; 4:00 a.m.
Orion has returned, but is currently a pre-dawn object in the eastern sky. Stars rise four minutes earlier each day as a consequence of Earth's orbital motion. So, as we move through autumn, Orion's belt will rise progessively earlier and by winter will become a prominent winter sky asterism.
7. b. white dwarfs
A white dwarf is a stellar remnant produced when any star less massive than 8 solar masses reaches the end of its life cycle. These stars expel their outer layers to form planetary nebulae. This "planetary nebula," -so named because of its resemblance to a planet when viewed telesopically- will then expand away from a white dwarf core. The composition of this core depends on the initial mass of its progenitor star. A very low mass star will produce a helium rich white dwarf, while a more massive star (that is will under 8 solar masses) will create a whigte dwarf rich in heavier elements such as neon and magnesium. [Note: white dwarfs lose thermal energy through the painfully slow radiative process. As they cool, white dwarfs exhibit different colors. Eventually, they'll turn to black dwarfs when they become sufficiently cool. Some white dwarfs might require about one trillion years to cool to the black dwarf state, a time period far exceeding the Universe's estimated age of 13.8 billion years. Consequently, no black dwarfs have yet been detected.]
8. a. the amount of energy it emits every second
A star's luminosity relates to its energy output. A star's luminosity is determined by its mass. The more massive the star, the more luminous it will be. Luminosity is also related to a star's size and temperature. If you double a star's size, its luminosity increases four time. If you double a star's temperature, its luminosity increases 16 times!
9. c. Galactic clusters have a lot more stars than globular clusters
This statement isn't true. A globular cluster contains hundreds of thousands or even millions of stars, whereas the galactic clusters consist of hundreds or thousands. Galactic clusters also tend to disassociate after a few hundred million years. (Our Sun was originally part of a cluster that has long since dissipated.) With ages often exceeding 10 billion years, globular clusters are amongst the oldest structures in the Universe.
10. a. The Local Group
The Local Group of Galaxies consists of more than 54 galaxies, most of which are dwarf galaxies. The Milky Way Galaxy and the Andromeda Galaxy are the two largest members. The diameter of this region just exceeds 10 million light years.
Omega Centauri
A globular cluster in the constellation Centaurus
Globular clusters are larger, older and contain more
stars than galactic clusters
Age: 11.5 billion years
(Image: ESO La Silla Observatory)
Pleiades Star Cluster
A galactic cluster in the constellation Taurus
Galactic clusters tend to contain a few hundred stars
and are quite young.
Age: 120 million years
(Image by NASA, ESA, AURA/Caltech, Palomar Observatory)
RATINGS:
10 CORRECT: SPACE SCIENCE SORCERER
You were conjuring over a cauldron while all the other kdis were outside playing capture the flag. You're a wizard on every level from the lunar to the cosmological. You could even be a Harry Potter character, but, of course if you are, you won't actually say anything or be involved in the plot.
7 - 9 CORRECT: COSMIC CRACKERJACK
Yes, we know you missed a couple of the questions on purpose so your friends will still think you're mortal. You are secretly soaring along the stratosphere and can ascend above the Karman Line whenever the mood moves you.
3 - 6 CORRECT: ASTRONOMICALLY AVERAGE
No worries! The Sun is an "average" star and well developed ancient warriors once thought very highly of it.
0 -2 CORRECT: LOOK ON THE BRIGHT SIDE
Your social life is intensely active and we envy you for it.
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FROM THE CATACOMBS OF INFINITE KNOWLEDGE
The development of the theatre predated the invention of electric lights. Before electric lights were available, a theatre would cast its stars in an intense light generated by burning lime in a lamp. From this practise we derive the term "limelight."
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