ASTRO MODULE 2
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School
Texas Christian University *
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Course
101
Subject
Astronomy
Date
Feb 20, 2024
Type
docx
Pages
10
Uploaded by GeneralBravery8521
Module 2 Astro Questions …
2.1*
From the article "What Are Celestial Coordinates," why is Right Ascension measured in hours instead of degrees?
Since the sky moves 1 hr of RA for every 1 hr of earth time, it makes it easy to track the motion
2.2 From the article "What Are Celestial Coordinates," on the sky, what reference point does the line of 0 hours of Right Ascension pass through?
The reference point that 0 hr RA passes through is the first point of aries = where the ecliptic crosses the celestial equator in pisces 2.3 From the article "What Are Celestial Coordinates," describe how precession affects the celestial coordinates of Polaris, what we currently call our North Star.
Precession is the act of the earths pole drawing a big circle in the sky completing every 26,000 years - once this is complete polaris will no longer be our north star
2.4*
From "Echoes, Chapter 2:" What (modern) constellation is associated with the “stretching of the cord” ceremony in ancient Egypt. Describe the evidence that leads astronomers to making this association.
There is evidence found at Dendra in the Temple of Hathor which provides that the pharaoh glanced to the Bull’s Thigh when conducting the ritual - which we know today to be the Big Dipper
2.5*
From "Echoes, Chapter 2:" What is the purpose of the "stretching of the cord" ceremony in ancient Egypt? What is it analogous to in today's society?
The purpose of the stretching of the cord ritual is to erect temples with the assistance of the gods in the cosmos through the pharaoh - this is analogous to the modern use of stars for surveying new buildings (could also be analogous to ceremonial christening of ships, since the pharaoh really didn’t do much)
2.6 From "Echoes, Chapter 2:'' In the study of the Cahokia Sun Circle, explain the significance of the discovery of a posthole offset 5 feet due east from the central posthole of the circle.
Answer. The significance of the discovery of a posthole is that it made the site's use as an observational solar calendar site more viable, as an observer would be able to stand atop this perch and better visualize the surrounding natural events.
2.7*
From "Echoes, Chapter 2:" By comparing the Cahokia circle to similar circles found in Virginia and Florida, the author makes an argument for and against the hypothesis that the Cahokia Sun Circle was mainly used for astronomical purposes.
Describe the evidence and how it supports or detracts from the astronomical hypothesis.
Answer. The offset post at Cahokia was a little bit different than the other sites which lacked offset posts - this raises the idea that the site could have had other uses, perhaps astronomical. The sites in Florida and Virginia were associated with non astrological rituals, so the fact that the Cahokia site is different could mean it is used for astronomy. A contradictory piece of evidence is that the size of the site is off from other astrological sites by as much as 20%...
2.8*
From "Echoes, Chapter 2:" Many different alignments for the windows are proposed in the passage about the Caracol in Chichen Itza, including the setting sun on the equinox, the extreme northern and southern moonsets, the extreme northern and southern setting locations of Venus and even the setting of the Pleiades. Why does the author argue that the equinox alignment of the largest window (window 1) is likely not an accurate interpretation?
Answer. The alignment of the window is offset by roughly 2 degrees from where the equinox would have been at the moment of observation, which is representative of more
than a week off from the actual time. In addition the author points out that for the alignment to make sense the observer would have to crouch into a very awkward position. It is more likely a tower dedicated to the observation of Venus.
2.9 From "Echoes, Chapter 2:" Why does the author argue (two reasons) that the most
likely alignment, if one exists at all, is to the extreme northern and southern setting locations of Venus? 1. Venus is the 3rd brightest object in the sky and 2. Venus follows a slightly offset path with relation to the sun (3.4 degrees) - the extremes of the planet coincide with the view of the observation holes
2.10*
From "Echoes, Chapter 2:" Near the end of the passage on the Caracol, summarize the two arguments the author makes (aside from possible alignments with various celestial events) that the Caracol was actually used mainly as an observatory.
Answer. It is elevated and reasonable to climb.
2.11 From "Echoes, Chapter 2:" Describe why the “official” sky measuring station in ancient China was located in the town of Yang-cheng. In other words, why was it appropriate for this station to be found in this town as opposed to anywhere else in China.
Answer. This town was viewed as the center of the world at the time.
2.12 From "Echoes, Chapter 2:" Explain how the sky measuring station worked: what did it measure and how?
Answer. The sky measuring station was a tower with a wall that measured its shadow against various markings denoting various times of year - to measure with extreme accuracy how long the year was going to be.
2.13 From "Echoes, Chapter 3:" List the seven days of the week, and for each day, match it with the celestial object the day is named for.
*look to spanish day translations*
Saturday = saturn Sunday = sun Monday = moon Tuesday = mars Wednesday = mercury Thursday = jupiter Friday = venus 2.14 From "Echoes, Chapter 3:" What was the main divine role of the Sun in the cultures described in the reading? What was the main divine role of the Moon in these cultures?
Answer. The sun was seen as powerful and dependable, therefore it is the source of all authority, law, and social order
The moon is quick to come and go, it is a great timekeeper (think moonphase of watch)
2.15*
From "Echoes, Chapter 3:" Of the two major nearby cultures that existed prior to the Greeks and Romans were the Egyptians and the Babylonians. Which of the two earlier cultures (Egypt or Babylon) was likely the primary source for the myths associated with the planets? Provide one example from the reading that supports this argument (for a given planet, describe how the Egyptian and Babylonian myths differ and which belief was adopted by later Western cultures).
Answer. The babylonians were a likely influence on the planetary god system of the greeks, a fairly obvious example of the similarity is the babylonian god marduk which is very similar to the greek god zeus - both are the king of the gods and both are associated with jupiter.
2.16 From "Echoes, Chapter 3:" What is the definition of the word “mercurial” and why is it appropriately linked to the behavior of the planet Mercury in the sky?
Answer - mercurial means erratic and fickle, we say this because mercury is just that as
it goes through the sky - erratic, for every 2 days it is visible there is 1 day where it is invisible
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2.17 From "Echoes, Chapter 3:" Describe two ways in which Egyptian culture identified
the ruling pharaoh with the Sun. For your reference, a "cartouche" is an oval enclosing a set of hieroglyphs that represent the name and title of a monarch.
The symbolism for the sun and the pharaoh are very similar - the sign for the rising sun and public appearance of the pharaoh are the same. The sun often appears on the pharaohs cartouche and the pharaoh wore a divine sun cobra on his crown.
2.18 From "Echoes, Chapter 3:" Describe what skybands are in Mayan culture and how they were used to identify members of the ruling class with the sky (stars or planets
or sometimes the sky itself).
Answer - the skybands are imagery derived from the cosmos that adorn the clothing of the elite ruling class. This is because knowledge of the cosmos was the basis for sustenance of the people, and it was reserved to the ruling class. This clothing signified they ruled with a nod from the gods.
2.19 From "Echoes, Chapter 3:" Describe how the gospel of St. Matthew identifies Christ with the sky.
Answer - the birth of jesus was hallmarked with the appearance of a brilliant star in the sky that drew in wise men from the east 2.20 From "Echoes, Chapter 3:" Explain the origin of the Christmas holiday. Why do we celebrate Christmas on December 25 instead of in April, the time of year most scholars believe Christ was born?
Answer - we celebrate christmas on the 25th of december because that was already a popular time for celebrations, and for a new religion it made sense for it to coincide with already accepted traditions. 2.21*
From the passage "Introduction to Archaeoastronomy," even though observations
of the sky were likely no more important than interactions with the surrounding landscape for ancient peoples, we feel that we can potentially learn more by studying how people observed the sky and how it influenced them. Explain wny.
Whereas landscapes can change humans have developed technology to see exactly what the ancients saw. We can directly observe their views and given their view of things we can extrapolate how they saw the rest of the world around them. 2.22*
From the passage "Introduction to Archaeoastronomy," briefly describe three potential problems (there are four mentioned) with using first-hand accounts to understand the ancient practices and beliefs of a particular society.
-
Ethnographers can be misled by informants -
Sacred info can be withheld -
Ethnographers may have their own biases that taint data we observe
2.23 From the passage "Introduction to Archaeoastronomy," briefly describe two ways (one example from Scotland and another from Central America) that we can distinguish between accidental (or serendipitous) and intentional astronomical alignments.
How can we distinguish between accidental and intentional astronomical alignments?
Accidental - has no rhyme or reason - an example of this is a temple down south in chichen itza, that upon first glance appeared to lack rhyme or reason but was alter substantiated through codices, testimonies, and calendrical data as an observatory used to track Venus Intentional - a way to ascertain the intentional nature of a building is to look to statistical evidence, for instance in scotland there were a set of hengelike buildings dedicated to lunar observation - since there were many that all shared similar phenomena it can be concluded they are all intentional
2.24 From the passage "Introduction to Archaeoastronomy," explain what is an intercalary month and why it was used in some ancient calendars.
An intercalary month is one used to round out calendar systems it was used to make a calendar align to the solar year 2.25 From the passage "Introduction to Archaeoastronomy," though not all civilizations follow this route, describe the "natural" three-step progression of calendar development that led to the type of calendar we use today.
1. Develop lunar calendar, 2. Insert seasonal events and omit/add intercalary dates where necessary to stay on track, 3. Integrate solar/luni calendar system to get to where
you no longer have to add/omit intercalary dates
2.26 From the passage "Equinox Alignments," equinox is sometimes defined as the time when day and night everywhere on the Earth are the same length (12 hours) or alternatively that it is the day when the time between sunrise/sunset is the same as the time between sunset/sunrise. Briefly describe four factors that make it difficult to precisely define the equinox by using "day length" definitions like this.
It is misleading to say the above because the E gets light before the sun rises and remains light after the sun sets, making the actual period of darkness at the equinox substantially shorter than 12 hours. In addition this definition assumes a flat horizon and
an absence of atmospheric effects, mainly refraction. 2.27 From the passage "Equinox Alignments," explain what is the astronomical definition of the equinox (there are two different ways described by the author, either one is fine).
The astronomical way to define the equinoxes is when neither pole of E is facing towards or away from the sun.
2.28*
From the passage "Equinox Alignments," the equinox is sometimes thought of as "the halfway point between the solstices." The author refers to measuring the equinox as a "halfway point in space or the halfway point in time." What does it mean to measure the "halfway point in space" and why might this definition depend on where you are observing from on the Earth?
When trying to pinpoint the date of the equinox you will have a hard time anywhere other than the equator as the sun will be rising at an angle due to your perspective being a challenge
When measuring the equinox as the halfway point in time, you would count the time between the solstices to find the date of the equinox - and unless standing on the equator the sun would rise at an angle, because the model does not take into account the observer's position on E. 2.29*
From the passage "Equinox Alignments," measuring the equinox as a "halfway point in time" is also referred to as the "Thom equinox." Describe two potential problems with determining an equinox in this way.
1.
The earth does not revolve around the sun at a constant speed - therefore the equinox can occur earlier or later than anticipated 2.
Using the half way point in time would be a challenge especially if you are not on the equator as the sun would rise at an angle leading to confusion for those without extreme astronomy knowledge 3.
The knowledge and tools needed to ascertain this exact date, equidistant between the two solstices, is rather complex. Identifying the Thom equinox requires an efficient system of recording or memorizing numbers of days up to at least 180 and presupposes that the solstices can themselves be defined to pinpoint precision which is not self evident 4.
The early societies would have little use and therefore motivation to figure this information out 2.30*
From the passage "Equinox Alignments," near the end of the passage, the author
argues that it is likely peoples in ancient Europe and Mesoamerica likely did not orient anything with respect to equinoxes (instead they oriented with cardinal directions East-
West, if anything). Explain two reasons why the author makes this argument (one example from Europe, the other from Mesoamerica).
The europeans did not tend to align their churches and tombs to the equinoxes, instead their alignments were seemingly more influenced by the sun In mesopotamia there is documented importance of the direction east, as well as sunrise against topographic landmarks as being used to measure dates of significance
In observing both of these examples of ancient cultures we see no effort being made to understand equinoxes, instead they tend to use things they understand well as they are closer to their proximity of understanding. Why go out of their way to introduce new concepts when what they have worked so well? No need to reinvent the wheel.
2.31 From "Star Tales -- Scorpius:" The original Greek constellation was much larger than the modern constellation of Scorpius. Describe how the constellation was split and
what the extra constellation is now.
The constellation was split by the romans in the first century BC, separating the body/stinger from the claws making a new constellation, Libra, the balance
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2.32 From "Star Tales -- Scorpius:" In Greek mythology, how is Orion related to the constellation Scorpius? In this story, why does Orion set while Scorpius rises?
Orion was slain by scorpius - they are set the way they are so orion sets as his conqueror rises
2.33 From "Star Tales -- scorpius:" The original Arabic name of the bright red star Antares was "kalb al-'akrab," which translates as what?
It means the heart of the scorpion
2.34 From the video "Crash Course: Phases of the Moon," describe what is our perspective on Earth during New Moon (where is the Moon in the sky in relation to the Sun). When does the new moon rise and when does it set?
We cannot see the moon because the opposite face of the moon is illuminated, the moon is nearly between the earth and the sun - the moon rises when the sun rises and sets when the sun sets. 2.35 From the video "Crash Course: Phases of the Moon," one week after the new moon, the moon is 90 degrees away from the Sun and half-lit in the sky from our perspective. Why do we call this phase first quarter?
We call this phase first quarter because the moon is ¼ through the full rotation cycle around the earth.
2.36 From the video "Crash Course: Phases of the Moon," describe what is our perspective on Earth during Full Moon (where is the Moon in the sky in relation to the Sun)? When does the full moon rise and when does it set?
The moon is opposite from the sun so the full moon is illuminated by the sunlight entirely, it rises at sunset and sets at sunrise
2.37 From the video "Crash Course: Phases of the Moon," if you were standing on the Moon during “New Moon” and looking at the Earth, in what phase would the Earth be?
You see the opposite, you would see a full earth 2.38 From the video "Crash Course: Eclipses," explain why we don’t get lunar or solar eclipses every month.
We don’t get eclipses every month because the moon has an orbital plane 5 degrees off
of the earth’s
2.39 From the video "Crash Course: Eclipses," explain the cause of the difference between an annular and a total solar eclipse.
When the sun is not fully covered by the moon as a result of the moon being on the far end of its orbit this is called an annular eclipse, if it is on the near end of its orbit this is a
total solar eclipse
2.40 From the video "Crash Course: Eclipses," why does the moon appear to be a deep red color during a total lunar eclipse?
The earth is starting to block the sunlight that hits the moon as it passes through the penumbra and the only light making it through is passing through the thickest part of our
atmosphere (which blocks green and blue light) leading it to appear as red 2.41 From the video "Crash Course: Eclipses," explain how the ancient Greeks were able to use lunar eclipses to show that the Earth is a sphere.
The shadow of the earth was round 2.42 From the video on the ancient Maya: According to Anthony Aveni, the civilization that built Chichen Itza lasted until about the 9th century AD. Aveni says there had been an advanced, progressive civilization in that region for about how many years? What are two lines of evidence that speak to their sophistication?
For more than 3,000 years - they had a system of writing, a complex calendar, observatories, etc.
2.43 From the video on the ancient Maya: Describe the phenomenon that occurs at the
Temple of Kukulcan on one of the two equinox days each year at sunset. Why doesn’t this phenomenon happen on other days of the year?
There is the impression of a serpents body as the sun sets - it does not happen every other day because the sun is not in the same spot
2.44 From the video on the ancient Maya: What is the apparent purpose of the 27.5 degree offset of the orientation of El Caracol?
It faces the exact position on the horizon where venus sets - 2.45 From the video on the ancient Maya: What is the apparent purpose of the “cockeyed” asymmetric corners of the platform on which El Caracol sits?
They point out the equinoxes - they are there to point out alignments where there are no
horizon markers
2.46 From the video on the ancient Maya: Without any complex tools, Anthony Aveni and his students describe how to construct a right angle using a circle.
They used a stake and a rope and used it as a compass to make a circle then wait another year and map out the necessary dates - use twine to make a right angle 2.47 From the video on the ancient Maya: Explain the evidence that supports the idea that the Temple of Kukulcan served as a kind of calendar (aside from the equinox phenomenon).
The temple has 365 total steps -
2.48 From the video on the ancient Maya: Explain how many days or years are represented in the Mayan calendar by the Tzolkin, the Haab and the Calendar Round. How is the Calendar Round related to the Tzolkin and Haab?
Tzolkin - has 20 periods with 13 days = 260 days Haab - agricultural calendar 365 days long used to schedule seasonal tasks Calendar round - super calendar, the calendar round lasts 52 years - the calendar ending was plenty stressful and had apocalyptic undertones To reduce anxiety they made a new long calendar 2.49 From the video on the ancient Maya: What were two lines of evidence to support the idea that the Mayan culture paid particular attention to the motions of the planet Venus?
Mayans used venus to predict the weather and used it as a symbol for when to go to war
2.50 From the video on the ancient Maya: Briefly describe a couple of reasons why the
Maya studied Venus so closely (i.e. what did they believe Venus affected here on Earth?).
They believed it could be used to predict the weather, and they used it to gauge when to
wage war
2.51 From lecture, why do we always see the same side of the Moon from Earth?
The moon rotates the same way it orbits so we only see the one side of the moon
2.52 From lecture, how often does the Moon rotate on its axis?
Every 27.3 days 2.53 From lecture, draw and label the Earth, Sun and Moon, indicate the direction of the Moon’s orbit, and label New Moon, Waxing Crescent, First Quarter, Waxing Gibbous, Full, Waning Gibbous, Third Quarter, Waning Crescent.
*****
2.54*
From lecture, explain the difference between the sidereal and solar month. Which
one is longer and why? Use a well-labeled diagram (like Figure B3 in your Annotated Diagrams file) to help explain, showing the spin of the Earth, the direction of the Moon’s orbit, the direction of Earth’s orbit and what causes the difference between the solar and
sidereal month. Both diagram and some explanation is required.
Sidereal month takes 27.3 days for the moon to orbit around the earth. Solar month is additional 2 days and the moon aligns itself between the earth and sun.
Peep diagram
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2.55*
From lecture, a common misconception about phases of the Moon is that they are caused by the shadow of the Earth falling on the Moon. Name and explain two lines of evidence that refute this misconception (I am not asking for the true cause of phases but rather evidence to refute this misconception).
The earths shadow does not cause the moons phases: we know this because
1.
If you look at the gibbous moon in the 1st quarter there is no way the earth could cast a crescent shaped shadow
2.
And other times the earth's shadow is visible in the sky while we can see the moon (reference “belt of venus”)
3.
Sometimes the sun and moon are visible at the same time - and it would be impossible for the sun (light source) to cause the E to cast a shadow on the moon with the given orientation
2.56 From lecture, another common misconception about the Moon is that it is only up in the sky at night. (a) During what time of day is the First Quarter Moon visible in the sky? (b) During what time of day is the Third Quarter Moon visible in the sky?
a. The first quarter moon rises around midday and sets around midnight b. The third quarter moon rises around midnight and sets at noon
The times this occurs is in direct contradiction to the common belief that the moon is only out at night 2.57 From lecture, explain why the angular size of the Moon is sometimes larger in the sky and sometimes smaller in the sky.
Sometimes the moon is actually closer to the earth and this distance can vary by up to 10% 2.58 From lecture, one more common misconception about the Moon is that it has a much larger angular size when it is close to the horizon and much smaller angular size when it is overhead. Explain a simple measurement you could make to refute this hypothesis (what measurements would you make, and what would they show).
You could take a point of reference, like the tip of a pen, and measure it against the moon when it is low and when it is high in the sky - i guarantee you it will be the same size 2.59 From lecture, what is a node? What is the line of nodes?
A node is when the moon crosses into the ecliptic 2.60
* From lecture, explain what are eclipse seasons and why we can only have lunar or solar eclipses about every six months.
The moon and sun only cross paths around every 6 months