Exam 1 Flashcards
a. When you stand facing North – looking at the North star on a clear night – to which side of you is East?
i. To your right
a. Imagine watching the sky and the stars & constellations around the North Star for several hours. Looking to the East you would notice new stars & constellations rising and looking to the West you would see stars & constellations setting. But the North Star… it would remain (very nearly) in the same spot in the sky. The North Star stays put while all other stars & constellations appear to revolve.
With this and your answer to the previous question in mind, how do all the stars & constellations appear to revolve around the North Star over the course of the night: clockwise or counter-clockwise?
i. Counter Clockwise
a. About how long does it take for all the stars and constellations in the sky to appear to revolve exactly once around the North star?
i. About 24 hours
a. identify six constellations that are circumpolar for us here in West MI, by selecting them in the list below.
o Ursa major o Ursa minor o Draco o Cepheus o Cassiopia o Camelopardalis
- Today, do our clocks tell daylight time or standard time?
o Standard Time
a. Each month, constellations cross the meridian____ earlier
2 hours earlier
• Asterism
o Group of stars
• Constellation
o Section of the sky
o 88 constellations in the sky
• stars rotate _____ around the north star
Counter clockwise
o When the left hand side of the moon is lit, it is a _____
Waining
o Full moons occur roughly ____ earlier than the month before
One day
How long is the lunar cycle
29.5 days
How long is each phase of the moon
3.5 days
The moon moves _____ around the sky
Eastward
o The moon rises about ___ minutes later each day
50
is the moon ever completely overhead
No, always a little south
How long is the moon’s sidereal period
27.3 days
Moon’s sidereal period
o This is how long it takes the moon to go completely around the sky and come back to the constellation it started in
o The line that divides the sky north and south is the ____
Meridian
Solar day - sun
meridian crossing to meridian crossing
varies a tiny bit periodically (seconds less, seconds more).
It is what our clocks are synced with (average of 24 hours over the length of the year)
Sidereal day - sun
23 hours and 56 minutes and it is the time it takes any star (besides Polaris) to go from meridian to meridian
o Compared to a solar day, the stars go around the sky ____ than the sun
Faster
How much faster do the stars go around the sky
(4 min faster each day, 30 min a week, 2 hours a month, or 6 hours a season)
o A day by the stars is ____ faster than a day by the sun
4 minutes
o The sun drifts ____ against the background stars
Eastward
o The ____ is the imaginary line that represents the path that the sun traces out over the course of a year
Ecliptic
o The ecliptic passes through all of the constellations represented in the ____
Zodiac
o List the Zodiac constellations
♣ Leo ♣ Libra ♣ Virgo ♣ Sagittarius ♣ Pisces ♣ Taurus ♣ Cancer ♣ Capricorn ♣ Gemini ♣ Aires ♣ Aquarius ♣ Scorpio ♣ Ophiuchus (the sun just recently started passing through it)
Which magnitude is higher, -3 or -2
-3
What is the brightest star in the sky and what is its magnitude
Sirrus; 0
• Ptolemy
o Greatest contribution to cartography was his latitude and longitude
o our latitude and longitude in Grand Rapids is
43 degrees N and 86 degrees W
• Average temperature of the sun is ____
6,000 degrees Kelvin
How many miles is 1 AU
93,000,000
• If a photon of light is created in the core, it takes ____ years for it to travel to the photosphere
1 million
• The sun is ___ light minutes away
7-8
• Hydrostatic equilibrium
o If the core got hotter, the sun would get bigger and brighter. Due to this increase in size, the sun would eventually shrink back down because the core can’t keep the sun that hot. Vice versa if the sun’s core got cooler
o The sun is nearly perfectly stable due to hydrostatic equilibrium
• Nuclear fission
o When a heavier element is split into two smaller elements
o Produces radioactive waste and runoff
o Usually happens at room temperature
• Nuclear fusion
o When two lighter elements are combined to make a larger element
o Most stars produce their energy through nuclear fusion
o Called hydrogen burning in astronomy
o In the core, hydrogen is slowly using its hydrogen and turning it into helium
o Only produces helium, nothing radioactive
o Requires very high temperatures, such as in the core of the sun
