lecture 1

Question 1

What is a super-moon?

why, what does it look like, characteristics, frequency

Answer 1

• occurs when the moon is at/near perigee
• occurs because the moon orbits the earth in an elliptical orbit
• appears 30% brighter bc it is closer to earth
• size differences are not visible with the naked eye
• occurs ~3-4 times a year; occured 4 months consecutively this year (2024)

Question 2

Perigee vs. Apogee

Answer 2

Perigee
- closest approach of the moon to earth
- looks larger and 30% brighter

Apogee
- furthest approach of the moon to earth
- looks smaller and dimmer

Question 3

What is the moon Illusion?

Answer 3

Moon appears larger when it is cloe to familliar terrestiral objects (trees, houses, horizon)
- moon’s apparent size does not change during the night

Question 4

What is a blue moon?

why, what does it look like, who came up with it

Answer 4

• when its the second full moon of the month
• moon cycle is 29.5 days; technically a month could have a full moon on the 1st and 30th (except february)
• when its the 3rd of 4 full moons of a season
• does not actually apear blue
• Farmgers Almanac came up with the term in the 1930s

Question 5

What does NASA/Boeing want to copy SpaceX on? What ship is NASA attempting to do this with?

Answer 5

their “space taxi” idea
- bringing astronauts and regular people into low eath orbit (LEO) (300-500km above earths surface)
- space x does this with their spaceship dragon

starliner is the ship NASA wants to use for taxi-ing

Question 6

What is Starliners “crewed mission”?

what happened, why it happened, why NASA did what they did,

Answer 6

• first half was successful; flew to international space station (ISS)
• during docking of ISS, starliners 28 thrusters behaved abnormally
• astronauts had to manually dock spacecraft
• could not return to earth; everything must be 100% perfect to go back through earths atmosphere + thrusters are necesary to return
• starliners crew are to remain in the ISS for ~8 months until dragon return them
• starliner will return to earth human-less
• NASA deemed thrusters not reliable enough for human use during re-entry
• NASA is very cautious with their astronatuats after accidentely killing 14 while ignoring the advice of their engineers.

Question 7

What is the importance of the night sky?

historical importance

Answer 7

survival
- crops and hunting were reliant on the position of the sun/stars and celestial motions for best times to crop/hunt
- prepare for seasons by observing where the stars are in the sky (winter = gathering food)

time keeping
- relied on where, and thus when the sun and stars aligned
- led to the development of the calender

Question 8

Name some early observations made about space.

earlier centuries

Answer 8

• planet means wanderer
• humanity realized that some lights in the night sky moved with a periodic motion (planets)
• planets shine by reflecting light from our sun (16th century)
• mercury-saturn were the first known planets
• sun is self luminous (produces vast amounts of energy); planets are not
• indigenous peoples invented many things related to astronomy (el caracol:observatory, majorville cairin and medicine wheel, stone hedge)

Question 9

Horizon vs Zenith vs Nadir

Answer 9

Horizon
- where the sky meets the ground

Zenith
- the point directly overhead

Nadir
- the point directly below

Question 10

Earths rotation and diurnal motion

what degree does earth rotate on, and what is diurnal motion

Answer 10

• Earth spins on an axis of 23.5 degrees
• diurnal motion is the daily motion of the heavens moving east to west; coincides with earths axis of rotation

Question 11

___ in the east, ___ in the west

fill in the blank

Answer 11

Everything (stars, moon, planets, sun) rises in the east, sets in the west
- everything rotates on the north/south pole; keave a camera pointing to the stars, leave it, and the stars will apear more west than before

Question 12

What does star motion apear to be at different latitudes: North pole, Equator, Intermediate latitudes (everywhere else)

imagine standing at each point; remember how earth rotates at poles

Answer 12

North/South pole
- stars circle zenith; do not rise or set
- 90 degrees latitude

Equator
- celestial poles on horizon; stars rise up and down
- 0 degrees latitiude

Intermediate Latitudes
- stars rise and set at an angle
- celestial poles between overhead and horizon

the stars dont move, planets do

Question 13

What is the celestial sphere?

what it is, how they were named

Answer 13

• the celestial sphere is an imaginary construct that allows us to place the sun, moon, and stars on a surface that surounds the earth; we are the observers
• sphere is divided into 88 sections (constelltions) containing all the stars within the celestial sphere
• indigenous culture named them after familiar animals/things; aspects of their culture

Question 14

Earths motions

moon, sun, earth, why we dont feel dizzy

Answer 14

moon
- spins 1500km/h around earth

earth
- moves around the sun at 30km/s
- moves through milky way at 225km/s
- earth is moving not the sun

we dont get dizzy because
- gravity
- earth is moving at a constant speed; we just move with it without noticing any changes

Question 15

Zodiacs

how many, where they got their names

Answer 15

there are techincally 13 (ophiuchus), but only 12 are recognized
- they go by different indigenous names

Question 16

How do seasons occur?

Answer 16

hemisphere tipping; If earth didnt have a 23.5 degree tilt, seasons would not exist
- when it is summer, your hemisphere tilts towards the sun; gives your area a more direct path of the suns energy

Question 17

How do sun rays affect seasons?

Answer 17

in summer, sun appears high in the sky, and its rays hit your hemisphere more directly; sun is above horizon for longer periods of time (more heat and sunlight)
- the rays spread less as it hits more directly
- suns path is focused on northern hemisphere

in winter, sun is lower in the sky, and hits your hemisphere less directly; sun rays are spread out over a wider areas, less concentrated heat
- spreading more
- suns path is focused on northern hemisphere

in spring/fall, sun is ‘middle’ of the sky, and hits your hemisphere an equal amount as the other
- spread equally
- suns path is focused on equator

north and south pole are always cold because the sun is least concentrated there

Question 18

moon cycle

how long, what it is

Answer 18

lunar phasing cycle is ~29.5 days
eliptical orbit (apogee and perigee)

Question 19

phases of the moon

8 phases

Answer 19

1. New moon (complete darkness)
2. waxing cresent (3/4 darkness)
3. first quarter (1/2 darkness)
4. waxing gibbous (1/4 darkness)
5. full moon (no darkness)
6. waning gibbous (1/4 darkness)
7. third quarter (1/2 darkness)
8. waning cresent (3/4 darkness)

we cant see the moon fully illuminated at all times because of our perspective on earth

Question 20

Why do we only see one side of the moon?

Answer 20

the moon rotates; allowing us to only see about 50% of it at any time
- other side does get illuminated by the sun; no “dark side” of the moon

it rotates on its axis the same rate at which it rotates the earth; most stable this way
- gives the moon 14.5 days of sun and dark

also because of earths gravitational pull
- ocea tides arise because of the moon and the earth rotating under that influence

Question 21

Lunar vs. Solar eclipse

Answer 21

lunar eclipse
- moons orbit is on a 5 degree incline
- occurs every ~6 months; takes hours to complete
- sun -> earth -> moon
- earth blocks all light to moon
- can be partial
- blood moon - total lunar eclipse; moon passing through the center of the earths shadow which gives an orange/red hue
- the light is diffused through earths atmosphere; long wavelength radiation passing through earths atmosphere reaching the moon

solar eclipse
- sun -> moon -> earth
- moon creates shadow on the earth which blocks suns light for ~7 minutes, twice a year at any given location on earth
- can be partial; moon is at apogee, cant block all of suns light (called annular eclipse)
- animals will get confused thinking its sunset
- we can feel temperature drop temporarily

Question 22

why is the Geocentric model wrong?

who created it, why its wrong, what is right?

Answer 22

created by Ptolemy
- was able to predict where planets would be (mercury, venus, mars, jupiter, and saturn)

it states that planets orbit earth, because earth didnt feel like it was moving; earth was considered the centre of the universe

earth is not geocentric its actually heliocentric
- sun is the center, not the earth

Question 23

Heliocentric universe

what is it, who developed it

Answer 23

• sun is the center, while other planets orbit the sun
• motion is governed by the motion of the sun

copernicus developed the heliocentric model in the 15th century
- he believed the geocentric model was wrong
- beleived sun was giving energy to earth; didnt make sense if earth was the center

he only published this theory on his deathbed

Question 24

Who was Kepler and Brahe?

Answer 24

they were astronomers of the 17th century
Brahe
- measured positions of objects in the sky

Kepler
- a mathematician who used his math to decide which model of the universe was correct
- verified the tycho crater, largest crater on the moon
- created 3 laws (keplers laws) about space

Question 25

What were Keplers 3 laws?

explain them

Answer 25

Keplers 1st law
- verified circular orbits were incorrect
- planets orbited the sun in elliptical paths (squashed circle
- circumference of a circle is defined by radius
- eccentricity, e, for an elipse is its measure of how far from circular the ellipse is (squashed meter)
- sun is the focus of the ellipse

Keplers 2nd law; law of equal areas
- planets move at different speeds around the sun; farther from sun = slower speeds
- closest point to the sun for a planet is called Parigelion
- farthest point to the sun for a planet is called Aphelion
- straight line joining a planet sweeps out equal areas in space in equal intervals of time (conservation of angular momentum)

Keplers 3rd law
- the orbital period around the sun of any object was related to its distance from the sun
- an astronomical unit (AU) is the average distance between earth and sun; further than the distance = more than one AU, less than the distance = less than 1 au
- the square (^2) of a planets orbital period is proprtional to the cube of the semimajor axis of its orbit
- if you define the semi major axis of the objects orbital ellipse in units related to the average distance of the earth from the sun, than its orbital period in years was (p^2 = a^3)

Question 26

how to solve Keplers 3rd law equation?

(p^2 = a^3)

Answer 26

P = years
a = astronomical units