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: 2459097.16
2020-2021:  V
            "The lion doesn't turn around when the small dog barks."
                      -Tip on how to not let things bother you.


THE DAILY ASTRONOMER
Friday, September 4, 2020
Remote Planetarium 83:  Week 18 Quiz

The Remote Planetarium has returned. So, too, have the quizzes.  We have
now completed week 18 of our astronomy course.     We will also include the
weekly skywatch section.

*1.  The "Local Standard of Rest"  refers to the average motion of stars
within ________ of the Sun.*
a.  10 light years
b.  100 light years
c.  10 parsecs
d.  100 parsecs

*2. Toward which constellation region is the Sun currently moving?*
a.  Orion/Taurus
b.  Vega/Hercules
c.   Leo/Virgo
d.   Ursa Major/Ursa Minor

*3.  How fast is the Sun moving toward the Solar Apex?*
a.  10.5 miles/second
b.  45 miles/second
c. 98 miles/second
d. 143 miles/second

*4. One parsec equals ____________ light years.*
a.  2.36
b.  2.82
c.  3.26
d.  4.56

*5.  Is the Sun moving more quickly relative to the North Galactic Pole or
toward the apex?*
a.  the North Galactic Pole
b.  the apex
c.  the speeds are equal
d.  astronomers haven't been able to determine if the Sun is moving more
quickly relative to the NGP or the apex.

*6.  Dark matter comprises ______% of the Milky Way Galaxy.*
a.  25
b.  48
c.  62
d. 84

*7. 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

*8. Why is "dark matter" so named?*
a.  because the material doesn't emit detectable radiation
b. because it is located outside the Milky Way Galaxy
c. because it is only visible in the UV spectrum
d. none of the above

*9. How many different types of neutrinos exist?*
a.  1
b. 2
c. 3
d. 1,459,382

*10. What observation led astronomers to conclude that dark matter
comprised much of the Milky Way Galaxy?*
a.  the detection of so many exo-planets in our region of the galaxy
b. the velocities of stars toward the outer part of the galaxy are higher
than expected
c. the spiral arms are tighter than expected
d.  all of the above
e.  none of the above

*11. How massive is the supermassive black hole located in the galaxy's
nucleus?*
a.  100,000 times more massive than the Sun
b.  1.3 million times more massive than the Sun
c.  4 million times more massive than the Sun
d.  11 million times more massive than the Sun

*12.  Which one of the following is NOT a name of a major galactic spiral
arm?*
a. Scutum-Centaurus
b. Perseus
c. Sagittarius
d. Horologium

*13. Astronomers recognize _________ main parts of the galactic halo.*
a. 1
b. 2
c. 3
d. 4

*14.  Approximately __________ stars are formed each year in the Milky Way
Galaxy.*
a. 1 - 2
b. 5 - 8
c.13 - 21
d. 34 - 45

*15.  Our solar system is located in the _______________.*
a. Perseus arm
b.Sagittarius arm
c. Orion Spur
d. Scutum-Centaurus arm

*16. The Milky Way Galaxy contains approximately __________________ stars.*
a.  50 billion
b. 150 billion
c. 300 billion
d. 600 billion

*17.  As of this week, astronomers have confirmed the detection of
_________exo-planets.*
a.  1200
b. 2400
c. 3780
d. 4330

*18.  The Milky Way probably contains about ____________ stellar mass black
holes.*
a. 100
b. 100,000
c 100 million
d. 100 billion

*19. The galaxy's mass equals about ____________ solar masses.*
a.  30 billion
b. 300 billion
c. 800 billion
d. 1.5 trillion

*20.  Approximately _______% of stars in the Milky Way are main sequence
stars.*
a. 20
b. 40
c. 65
d. 92.5

ANSWERS
*1.  The "Local Standard of Rest"  refers to the average motion of stars
within ________ of the Sun.*
d.  100 parsecs
Nothing rests.   However, by averaging the motions of stars within 100
parsecs of the Sun, astronomers have defined a "resting plane" within our
part of the galaxy.

*2. Toward which constellation region is the Sun currently moving?*
b.  Vega/Hercules
Every star is moving in some direction.  Currently, the Sun -and by
extension, the solar system= is moving toward a point in the Vega/Hercules
region.
Astronomers call that point the "solar apex."

*3.  How fast is the Sun moving toward the Solar Apex?*
a.  10.5 miles/second
Though the pace is comparatively glacial, our motion toward the Solar Apex
is inexorable.

*4. One parsec equals ____________ light years.*
c.  3.26
A strange unit of measurement.    A parsec is the distance at which a disc
with a diameter equal to Earth's orbital radius would subtend an angle of
one arc-second.

*5.  Is the Sun moving more quickly relative to the North Galactic Pole or
toward the apex?*
a.  the North Galactic Pole
The Sun is moving more than 137 miles per second relative to the North
Galactic Pole. but only about 10.2 miles per second toward the Solar Apex.

*6.  Dark matter comprises ______% of the Milky Way Galaxy.*
d. 84
Most of the galaxy consists of matter we can't directly observe.    While
dark matter comprises about one quarter of the material in the physical
Universe, it represents most of the material in the Milky Way Galaxy.

*7. 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.

*8. Why is "dark matter" so named?*
a.  because the material doesn't emit detectable radiation
Astronomers have learned about remote celestial objects by studying the
electromagnetic radiation these objects emit.  Dark matter is only
detectable indirectly.

*9. How many different types of neutrinos exist?*
c. 3
The three types are electron, muon, and tau.

*10. What observation led astronomers to conclude that dark matter
comprised much of the Milky Way Galaxy?*
b. the velocities of stars toward the outer part of the galaxy are higher
than expected
If the only matter in the Milky Way Galaxy is visible, the velocities of
stars would decrease with increasing distance from the galactic nucleus.
  The stellar velocities are much higher toward the outer galaxy than were
expected.    This observation led astronomers to estimate that most of the
galaxy consists of dark matter.

*11. How massive is the supermassive black hole located in the galaxy's
nucleus?*
c.  4 million times more massive than the Sun
Supermassive black holes occupy the nuclei of all spiral and elliptical
galaxies.

*12.  Which one of the following is NOT a name of a major galactic spiral
arm?*
d. Horologium

*13. Astronomers recognize _________ main parts of the galactic halo.*
c. 3
Stellar halo, Galactic corona, and dark matter halo.

*14.  Approximately __________ stars are formed each year in the Milky Way
Galaxy.*
b. 5 - 8
About three solar masses of material are converted into stars each year.
Since most stars are less massive than the Sun, astronomers estimate that 5
-8 stars are formed from this material annually.

*15.  Our solar system is located in the _______________.*
c. Orion Spur
We do not live along a major spiral arm.  Instead, the solar system is
located along a spur, a minor bridge of stars within the galaxy.

*16. The Milky Way Galaxy contains approximately __________________ stars.*
c. 300 billion


*17.  As of this week, astronomers have confirmed the detection of
_________exo-planets.*d. 4330
Based on these detections, astronomers estimate that the galaxy might
contain about one trillion stars.

*18.  The Milky Way probably contains about ____________ stellar mass black
holes.*
c 100 million
This estimate is based on detections of neutron stars.   Both neutron stars
and black holes are formed by the explosions of highly massive stars.

*19. The galaxy's mass equals about ____________ solar masses.*
d. 1.5 trillion
This mass estimate is based on observations about the galaxy's rotation
rate.   The faster the rotation, the more massive the galaxy.

*20.  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.

____________________________________________________________________________________

*SKYWATCH HOTLINE:  September 4 - 10, 2020:*



On September 4th the Sun will rise at 6:09 a.m. and set at 7:10 p.m, giving
us 13 hours and 1 minute of daylight, a 2 hour, 25 minute decrease since
the summer solstice.  On September 10, the Sun will rise at 6:15 a.m. and
set at 6:59 p.m, providing us with 12 hours and 44 minutes of daylight. The
Sun continues to move through the constellation Leo the Lion.


The moon progresses through the waning gibbous phase until September
10th,when it will reach last quarter.   On September 6th, see the moon near
the planet Mars.  See them both by 9:30 p.m. in the eastern sky.  Both
bodies will remain visible for the remainder of the night.




*Mercury*  will not be visible this week. *Venus,* as always the brightest
planet, currently occupies the Cancer constellation and will rise at 2:26
a.m. on September 4th.  The optimal time to view Venus is between 3 - 5:30
a.m, when the brilliant planet remains visible against the pre-dawn glow.
At magnitude -4.1, Venus shines fourteen times more brightly than Sirius.
*Mars* rises by 9:06 p.m.  As it is currently located just north of the
celestial equator within the constellation Pisces, Mars rises just north of
east and will remain visible for the rest of the night. At magnitude -1.9,
Mars outshines all the stars.   Mars will continue to rise earlier and grow
brighter as it approaches its next opposition on October 13, 2020.
*Jupiter*, located in the constellation Sagittarius, begins the evening
high in the southeastern sky.  At magnitude -2.4, Jupiter outshines all the
night sky stars and planets, save Venus.  Jupiter sets at 1:27 a.m. at the
beginning of the week.  Jupiter reaches opposition again on August 19,
2021. *Saturn, *which is also within the constellation Sagittarius, is
considerably dimmer than Jupiter (magnitude 0.3), but occupies the same
general night sky region.     Saturn sets at 2:09 a.m. at week's beginning.


The brightest International Space Station fly-over occurs on September
10th.

The ISS appears at 5:01:05 a.m. and reaches its maximum altitude of 75
degrees at 5:04:05 a.m.At that time, the station will shine at magnitude
-3.6, making it appear seven times brighter than Sirius.   The ISS will
move toward the southeastern sky and set at 5:09:32 a.m.


[image: PassSkyChart2.png]




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