Astronomy Midterm Review Flashcards
(338 cards)
1
Q
What is the definition of Astronomy?
A
Astronomy is the study of objects and their interactions with each other beyond planet Earth
2
Q
What is the definition of Science? and what does it generate?
A
Science itself is a process, as Science is when we attempt to generate a method to create a common understanding of how nature behaves.
Science generates series of approximations of the natural world
3
Q
What is the three processes of the Scientific Method?
A
- The first step is when you gather data, through observation
- You then create a model from your observations
- After creating the model, you test the model to see if your data agrees with your model
If the data doesn’t agree with the data, then you must change the model, however if it does, you are able to create a general theory after many steps
4
Q
What is a Hypothesis?
A
A Hypothesis is an educated guess that is able to be tested. In other words, you try to explain why the unknown behaves the way it does
5
Q
What is a Theory?
A
A Theory is a hypothesis that has been repeatedly tested in multiple ways by multiple scientists, which results in a general consensus of what the best current understanding/approximation of the unknown
6
Q
What is a Consistent? (Hallmark of Science)
A
A consistent is when the results of repeated observations and experiments about a natural phenomenon are within the same range
7
Q
What is an Observable? (Hallmarks of Science)
A
The phenomenon you are trying to explain must be observable, either through a controlled creation of an event in a lab, or by observing nature itself
8
Q
What is a Natural Mechanism? (Hallmarks of Science?)
A
In order to be considered science, a natural mechanism must be present to explain the cause of the phenomenon
9
Q
What is a Testable Prediction? (Hallmarks of Science)
A
Any sort of explanation of a phenomenon must have a prediction that can be observed/measured
10
Q
What are the two Foundational Principles? (Hallmarks of Science)
A
- Our minds are changed when new data demands it because scientific explanations are always subject to revision and correction if new data arises
- Everything must be debated by multiple scientists to confirm authenticity
11
Q
What is a Built-in Assumption? (Natural Law)
A
A built-in assumption assumes that the universe is orderly, reasonable, and testable, as the laws of nature are the same everywhere in the universe
12
Q
What is the Scientific Notation
A
Since Astronomy frequently deals with very large numbers, a scientific notation is used to write large numbers in a more compact way
13
Q
What is an example of the Scientific Notation?
A
Distance to the Sun: 150,000,000 km = 1.5 x 108 km
4x1015 = 4,000,000,000,000,000
14
Q
What are Unit’s, and what are their purposes?
A
Scientists will present evidence, often in the form of measurements. Units are used to accompany a value to create a measurement.
15
Q
What is the definition of a Light-Year Unit?
A
A Light-Year is the distance that light travels within one year
16
Q
How fast does light travel?
A
Light travels at a speed of 300,000 km/s
17
Q
How far is 1 light-year?
A
1 light year = 9.46 x 1012 km
In other words, almost 10 trillion kilometres
17
Q
How does light-year work?
A
When you look at something that is one light-year away, you are actually perceiving it how it was a year ago
18
Q
How does light-year correlate to looking “back in time”?
And what pros and cons arise from this?
A
When looking at a sky object that is a light-year away, you are perceiving it how it was a year ago. In other words, you are looking one year into the past
While it does enable us to label the distance between sky objects, it sets a limit on how quickly we can observe/learn about events within the universe
19
Q
If a star that was located 4720 light-years away enters our telescopes, how long has the light been traveling through space? And what year would we have to wait until we can take a picture?
A
The light has been traveling through space for 4720 years. If we wanted to take a picture of the light, we would need to wait an additional 4720 years in order to take a picture
20
Q
How big is planet Earth?
A
About 13,000 km wide
21
Q
How big is the Solar System?
A
About 50 x 1013
or 2 light-days wide
22
Q
How big is the Sun?
A
About 1,392,700 km wide
23
Q
What is a star?
A
A star is an object that is mainly made of plasma which is held together by gravity, which results in a glowing ball of gas that can generate light through nuclear fusion
24
What is a planet?
A planet is a moderately large object that orbits a star, and shines by reflected light emitted from the star
25
What characteristics can planets have?
Planets can be rocky, icy, or even gaseous in their composition
26
What is the Milky Way Galaxy?
The Milky Way Galaxy is comprised of a collection of stars that can be seen by the unaided eye
27
How big is the Milky Way Galaxy?
The Milky Way Galaxy is as big as a 100,000 -light-year sphere
28
What are Nebulae's?
| Typically found in the Milky Way Galaxy's
A nebula is a cloud of gas and dust within the Milky Way Galaxy
29
What are Globular Clusters?
| Typically found in the Milky Way Galaxy's
Are a cluster of stars within the galaxy
30
What is the nearest major galaxy to the Milky Way?
The Andromeda Galaxy which is 2.5 million light-years away from it
31
What is the Cosmic Calendar?
A scale that compresses the history of the universe into 1 year
32
What is the timeline within the Cosmic Calendar?
| Major months: January, May, September, October, November, & December
January: The Big Bang Occurs
May: The Milky Way Galaxy Forms
September: Our Solar System Forms, beginning life on Earth
October: Earth's atmosphere becomes oxygenated
November: First complex life forms appear
December: Leads up to the presence of humans
33
What is the December Timeline in the Cosmic Calendar?
| Major dates: 19th, 20th, 25th, 26th, 30th, 31st
19th: Vertebrates appear
20th: Land plants appear
25th: Dinosaurs appear
26th: Mammals appear
30th: Dinosaurs become extinct
31st: Humans appear
34
What is science, and what is not science?
Science is not only a body of facts, but rather a process that attempts to explain how something in nature works
35
Why can Astronomy be considered as Observational Science and Historical Science?
Observational Science b/c: Astronomers create tests from observing many samples of the certain object of study, while also noting down important information on how each sample differs
Historical Science b/c: Anything that was observed had already happened in the universe, and cannot can be changed
36
What is the main fundamental assumption made about the universe? and why must we make this assumption?
The same laws apply everywhere in the universe. For example, the law that determines the motions of stars in space are the same exact laws that determines the arc of a baseball after being hit by a batter
The reason why we make this assumption is that astronomers would not make much progress since the laws are inconsistent. Astronomers would not be able to determine what happened in other "neighborhoods"
37
How far is the nearest star?
The nearest star to us is a system called *Alpha Centauri* which is about 4.3 light-years away
38
Why is travel time (light-years) such a tremendous benefit to astronomers/scientists?
If astronomers wanted to learn about how the universe came to be, they need to find the evidence about each period of time of the past
39
What is the distance from the Sun to the Earth?
150 million kilometers away
40
What is in our solar system?
Our solar system is comprised of eight planets, along with their moons and smaller bodies such as dwarf planets
41
What is dark matter?
Dark matter that cannot be currently observed with our instruments, however we know that dark matter is present because of the pull it exerts onto the stars and raw material we CAN observe
Everything else about dark matter are unfortunately unknown
42
What is the closest galaxy outside of the Milky Way?
Two dwarf galaxies that lie 200,000 light-years away
43
What is the Magellanic Clouds?
The Magellanic Clouds are two other galaxies that lie beyond the Sagittarius dwarf galaxy
44
What is the Local Group?
The local group is a certain part of a supercluster of galaxies, which were called the Virgo Supercluster
45
What is the Virgo Supercluster?
A supercluster of galaxies that stretches over a diameter of 110 light years
46
What is the most abundant element within the Universe?
Hydrogen
47
What is the structure of an atom?
The structure of an atom consists of a central, positively charged nucleus which is surrounded by negatively charged electrons
Bulk of the matter of atoms are found in the nucleus, which consist of positive protons and electrically neutral neutrons which are bounded tightly together in a small space
48
How many stars can be seen with the naked eye? and do they all belong to the Milky Way Galaxy?
Looking up, the naked eye can see 3000 stars, as well as the Milky Way Galaxy. All stars we see in the sky are part of the Milky Way Galaxy
49
What is the Celestial Sphere?
Whenever we look up at the sky, we fall under the impression that the sky is a dome shape that stretches from horizon to horizon
50
What are the characteristics of a Celestial Sphere?
| What is the North & South Celestial Pole, Celestial Equator, & Ecliptic?
North Celestial Pole: The point directly above Earth's North Pole
South Celestial Pole: The point directly above Earth's South Pole
Celestial Equator: An extension of Earth's equator onto the sphere
The Ecliptic: Is a pathway the Sun takes on the Celestial Sphere throughout the year
51
What is the Zenith point?
The point that is directly over your head
52
What is the Horizon?
A point where the 'sky dome' meets the Earth in all directions
53
What are Latitude and Longitude?
and what are their Zero points?
Latitude: Position North or South of Equator (Up or down)
Zero point = The Equator
Longitude: Position East or West of Prime Meridian which runs through Greenwich, England (Right or left)
Zero point = The Prime Meridian
54
How does Latitude affect the Sky visible to you?
It determines what part of the encircling star you are able to see
55
What happens to stars near the North Celestial Pole?
They never set
56
What happens to stars near the South Celestial Pole?
We cannot see them
57
What is the relationship between the altitude on the sky of the celestial pole to a local observer, and the local observer's latitude on the planet?
The altitude of the Celestial Pole equals the observer's Earthly Latitude
58
What are the Zodiac Constellations tracing the motion of?
Tracing the motion of stars throughout the sky
59
What is Altitude and Azimuth? How do we define them in the sky
Altitude: The height of the object in relation to sea/ground level
Azimuth: The direction of a celestial object from the observer
60
What is the Meridian
The line that passes through the Zenith point, connecting the North and South points on the Horizon
61
How can you use hands to measure angular size in the sky?
Holding your pinky= 1 degree
Holding three fingers up = 5 degrees
Holding a closed fist = 10 degrees
Holding index and pinky up = 15 degrees
Holding pinky and thumb up = 25 degrees
62
What is the angular size of a full circle? (What is that in Arcminutes?, and in Arcseconds?)
A full circle is 360 degrees
If:
1 degree = 60 arcminutes
1 arcminute = 60 arcseconds
A full circle would have 21,600 arcminutes, and 1,296,000 arcseconds
63
What's the difference between angular size, and physical size of an object?
Angular Size: is the 'apparent size' of an object. Since objects far away appear smaller, you're measuring the angle it takes up in your vision
Physical Size: Is the actual true size of the object, however it is hard to find the actual size of far away objects.
64
Why do Constellations depend on Both the Observer's Latitude, and the Time of year?
Your position on Earth determines which constellations stay below the horizon
Time also matters because the Earth's orbit changes the location of the constellations
65
What is the definition of a Constellation?
A constellation is a region of the sky with specified boundaries
66
What is the difference between the 'classic' and modern definitions of constellations?
The modern definition states that a constellation is only a region of the sky with specified boundaries
Whereas a classic definition of a constellation consists of the pattern the stars create
67
How many official constellations are there?
88 official constellations
68
What is Right Ascension? (and zero point)
Similar to longitude, it measures 'around' the celestial sphere (left to right)
The zero point is at the Vernal Equinox
69
What is Declination? (and zero point)
The same as latitude, it measures the distance from the celestial equator towards either pole
Zero point is at the celestial equator
70
What is the declination of both North, South, Celestial Pole, and the Celestial Equator?
North Celestial pole = 90 degrees
South Celestial pole = -90 degrees
Celestial Equator = 0 degrees
71
How much is the Earth's axis tilted from the Ecliptic plane Around the Sun?
The Earth's axis is tilted about 23.5o from the Ecliptic Plane around the sun
72
Where is the Axial Tilt pointed at?
Always pointed in the same direction (which is towards Polaris in the North, and Sigma Octantis in the South)
73
Where is the Earth's North & South Pole pointed in the sky?
Earth's North Pole is pointed towards the North Celestial Pole in the sky, while the South Pole is pointed towards the South Celestial Pole in the sky
74
What are two reasons that explains why Earth's rotation cause temperature differences?
1st: It changes the concentration of light as higher concentration means hotter temperatures and vice versa
2nd: The time the sun spends above the horizon also depends on the tilt
75
Why do we have seasons? and how does it work?
Season's occur due to the Earth's axial tilt (23.5 degrees)
As the Earth travels around the Sun, in June, the Northern Hemisphere 'leans into' the Sun more, which exposes the sunlight more directly.
The situation becomes the opposite during December, as the Southern Hemisphere leans into the sun, and the Northern Hemisphere leans away
76
How do seasons work in the Northern Hemisphere, compared to the Southern Hemisphere?
Say if the Northern Hemisphere points towards the sun, that hemisphere is now summer, and the southern hemisphere is assumingly winter since there's no sun
This can also be applied vice versa
77
What can we use to mark the changing of the seasons?
| And what are the signifances of these days throughout the year?
We can indicate the change of seasons from Solstices, and Equinoxes
78
When is the Summer Solstice and what happens on this day?
The Summer Solstice occurs around June 21st, which is when the Sun shines down most directly on the Northern Hemisphere, and is the longest day of the year
79
When is the Winter Solstice? and what happens on this day?
The Winter Solstice happens around December 21st, which is a day where the Sun shines on the Northern Hemisphere it's most indirect, and is one of the shortest nights
80
When are both Equinoxes and what do they do?
Equinoxes typically happen during March 21st, and September 21st. This is typically when the Sun equally shines on both hemispheres. Giving equal amounts of light and darkness.
81
What is the Perihelion? And what is the Aphelion?
The Perihelion: means that the object is closest to the sun
The Aphelion: means that the object is farthest away from the sun
82
What time of year is Earth the closest to the sun, and the farthest from the sun?
Earth is closest to the Sun in Early January
Earth is the farthest from the Sun in early July
83
Why doesn't Earth's change in distance affect the seasons? What would be the scenario if distance did change things?
Because the sun would eventually shine onto the Earth because of the Earth's axial tilt. If it was the case, North and South would have the same seasons at the same time, and Summer would be in January
84
What are Phases of the Moon?
| What are Primary Phases and Intermediate Phases?
Primary Phases: Occur at a specific moment in time
Intermediate Phases: Only occurs between Primary Phases
85
What are the four Primary Phases?
1. New Moon
2. First Quarter
3. Full Moon
4. Third Quarter
86
What are the four Intermediate Phases?
1. Waxing Crescent
2. Waxing Gibbous
3. Waning Gibbous
4. Waning Crescent
87
What are all the Moon phases together?
1. New Moon
2. Waxing Crescent
3. First Quarter
4. Waxing Gibbous
5. Full Moon
6. Waning Gibbous
7. Third Quarter
8. Waning Crescent
88
What does Waning and Waxing mean?
Waning = Shrinking
Waxing = Growing
89
What is the Sidereal Period, and the Lunation Period? What's the difference?
The Sidereal Period: Is the time for the Moon's actual orbit around the Earth which is 27.3 days
What is the Lunation Period?: Is the time between successive reoccurrence of the same phase (new moon to next new moon) which takes 29.5 days
The difference is that the Sideral Period is how long the Moon takes the complete it's orbit, and the Lunation Period is how long it takes for the Moon to go from the phases "New Moon to New Moon"
90
Why do we only see ONE side of the Moon? What can it also be called?
Because the Moon rotates on it's North-South axis one full rotation in exactly the same time it takes to orbit the Earth.
In other words, the Moon rotates the same speed as it orbits the Earth
It can also be called a 'synchronous rotation' or 'tidally locked'
91
Why is the Moon tidally locked?
Tidal forces aim to elongate the Moon in the direction of the Earth. As the Moon spins faster, the part of the Moon that faces the Earth starts to stretch, causing a mis-alignment because it takes time to shift that much rock.
Since the tidal bulge is always mis-aligned, the Earth would try to pull it back to alignment, causing it to slow down it's rotation
92
How does location on Earth affect gravity?
Since the Moon's gravity pulls on the Earth's surface unevenly, the gravity is at it's strongest closest to the Moon, and is weakest at the spot farthest from the Moon
93
What is a Tidal Force?
A Tidal Force is the difference between the gravitational attraction of the solid Earth towards the Moon, and the gravitational attraction at a specific point in the ocean
94
What are Spring Tides, and What are Neap Tides?
Spring Tides: Tides are higher than usual, and occur during full and new moons
Neap Tides: Only appears after a spring tide, which refers to a period of moderate tides when the sun and moon are at right angles of each other
95
What are the three different types of Solar Eclipses?
Partial: The Moon partially covers the sun
Annular: The Moon covers the sun however there is a sun outline around the moon
Total: The moon fully covers the Sun
96
When do Solar Eclipses happen?
Solar Eclipses happen during a New Moon
97
What happens during Solar Eclipses?
It happens when the New moon moves between the Earth and the Sun, resulting in the three celestial bodies to form a straight line, or almost a straight line
98
What happens on Lunar Eclipses?
Lunar Eclipses result when a full moon falls into the Earth's shadow, resulting in the Moon having a reddish hue
99
What is the difference between a Solar Eclipse, and a Lunar Eclipse?
A Solar Eclipse involves the New moon going between the Sun and the Earth, essentially covering the sun
A Lunar Eclipse involves a full moon falling into the Earth's shadow from the Sun
100
Why does the Moon turn red during Lunar Eclipses?
The Moon turns red because the only light that goes onto the Moon are sunlight that passes through the Earth's atmosphere
101
What does Circumpolar mean?
| Provide an example
Circumpolar means that the object is continuously visible above the horizon, no matter if its day or night
For example, stars within 38o of the North Pole never sets, and are always visible, therefore Circumpolar
102
How does the Ecliptic relate to the Zodiac?
The constellations are called the 'zodiac' and all lie on the Ecliptic path
103
How does Planet's act in the sky, and what do they mean?
Planets tend to change their positions slowly from day to day
The word Planet means 'wanderer' in ancient Greek
104
What is the Arctic Circle?
As the Earth rotates on its axis, all places within 23o of the North Pole are continuously illuminated by the sun
In other words, that area is exposed to the sun for 24 hours
105
What is the Antarctic Circles
All places within 23o of the South Pole do not see the Sun at all for 24 hours
106
What makes Solstice and Equinox special?
Solstice's: Are the longest and shortest days of the year
Equinoxes: Are times when the day and night are equally as long
107
How are Seasons affected by Latitude?
As we travel more North or South, the seasons become more pronounced (more hot/more cold)
108
Explain the Astronomical roots of the names for the days of the week?
Within Western culture, the seven days of the week were named after the seven wanderers that the ancients saw in the sky
The Sun, The Moon, and the five planets visible to the unaided eye (Mercury, Venus, Mars, Jupiter, and Saturn)
109
Why does the phrase 'dark side of the Moon' not make sense?
Since the Moon rotates, the Sun rises and sets on all sides of the Moon, meaning that there is no dark side of the Moon
110
What is the Definition of Differential Forces? and Why does this happen?
Since the Earth is not fully rigid, the differences in the Moon's attraction on different parts of the Earth can cause the Earth to distort slightly
This is because the side of Earth nearest to the Moon is more attracted to the Moon than the Moon's attraction towards the middle of the Earth
111
How are tides formed on Earth?
Tide-raising forces produce motions in the water that create tidal bulges in the oceans. The water on the side of Earth facing the Moon will flow towards it. It will also do this on the opposite side
112
What are Eclipse Seasons?
Eclipse seasons is when the Moon crosses paths with the Ecliptic Plane, which allows Eclipses to happen
113
What is the Umbra? And what is the Penumbra?
Umbra: The cone where the shadow is darkest
Penumbra: The cone where the shadow is lighter and a more diffuse region
114
What is the Corona of the sun? And how can we see it?
The Sun's corona is the Sun's outer atmosphere that consists of sparse gasses that extend for millions of miles in all directions
It can be visible during a total eclipse, where the Moon will have a shiny light around the Moon
115
Why are Lunar Eclipses easier to see than a Solar Eclipse?
It is because the Lunar Eclipse can be visible to anyone who sees the moon. It is also because Lunar Eclipses can be seen entirely through the night
116
What are some of humanity's connections to astronomy socially, philosophically, and practically?
| There are 4
1. Keeping Track of time and seasons (practical, social, agricultural, and religious)
2. Keeping track of lunar cycles
(calendar, agricultural, and religious)
3. Keeping track of planetary cycles
(religious, and societal)
4. Aiding navigation
(practical)
117
How do we know that Ancient Humans had a good grasp at the patterns of astronomy?
| Atleast two ancient groups
1. Ancient people of central Africa were able to predict seasons based on the orientation of the crescent Moon
2. Ancient Egyptians were able to track the sky for time keeping, so they could accurately predict when the river was going to flood
118
Who is Ra? and how was he worshipped?
Ra is the God of the Sun and the King of all Egyption Gods
Egyptian religion worshipped Ra at night, in order for Ra to rise again the next morning
119
How was ancient Egyptian astronomy interwoven into the daily and annual life of the people?
The Egyptians had their own system when it came to time keeping
120
How did Egyptian Time Keeping work?
Egyptians identified a list of constellations which makes their helical rise roughly every 10 days (their year was originally 36 weeks of 10 days long)
They found 36 constellations that could be used to determine how close they were to sunrise
121
Who were the other cultures that understood astronomical ideas?
Polynesians: Very skillful in the art of celestial navigation
France: Cave paintings from 18,000 BCE suggested their knowledge of lunar phases
China: Earliest known records of supernova explosions (1400 BCE)
122
What is Cosmology?
Is the basic structure and origin of something
123
How did ancient people know that the Earth was spherical?
| Two reasons:
Ancient Greeks knew the Earth was round because
1. The Earth's shadow is curved
2. If you were to travel south for a significant distance, new constellations are revealed which are only possible on a spherical Earth
124
What is the Heliocentric model? and how was this conclusion found?
Aristarchus correctly deduced that the Earth orbited the Sun
He found this answer based on his measurements of the sizes and distances of both Sun and the Moon
125
What was the Geocentric Model?
It was suggested that the Earth is at the center of the Universe and that objects move on perfect spheres/move in perfect circles
126
What did Plato and Aristotle believe?
Both believed in the universe being Geocentric, however the Geocentric model resonated with Aristotle more
127
What was the problem with the Geocentric model?
It wasn't able to explain the apparent retrograde motion of planets
128
How were the motions of the Planet explained in Ptolemy's geocentric model?
A planet would circle around a smaller circle, and that small circle would go around a bigger circle
129
How did the rise of the Islamic world contribute to our understanding of Astronomy?
The rise of Islam and the Muslim world preserved and enhanced the knowledge they received from the Greeks when Europe fell into the dark ages
130
What is the Al-Mamun's House of Wisdom?
The world's foremost learning Centre in Baghdad
131
What did Aristotle cite in his arguments that the Earth was spherical?
| Two arguments
First argument: He argued that when the Moon enters or emerges from the Earth's shadow during an Eclipse, the shape of the shadow on the Moon can be seen as round, as only round objects can create round shadows
Second argument: His also argued that travelers who were to go a significant direction towards the south are able to observe stars that cannot be visible in the far north. If the Earth were to be flat, we would all see the same stars overhead, which also indicates that Earth is round
132
Who was Aristarchus of Samos?
Aristarchus was an ancient Greek astronomer who pushed the idea that the Earth was moving around the Sun
133
What is *Stellar Parallax?*
Is the term used to describe the shift in the apparent direction of a star due to the Earth's orbital motion
134
What was the experiment Eratosthenes did to measure the Earth?
Eratosthenes first observed the angle by how the Sun rays hit the planet's surface. Because the Sun rays were parallel, he knew that a ray at Syene came straight down, whereas a ray at Alexandria made an angle of 7o. In effect, going from Alexandria to Syene, had caused the Earth's surface to curve away by 7o, or 1/50 of a full circle. Which meant that the distance between both cities must be 1/50 the circumference of Earth itself
135
Who was Hipparchus? and what did he Discover?
Known to be the 'greatest astronomer of antiquity' and made one of the most remarkable discoveries.
Hipparchus discovered that the position in the sky of the North Celestial Pole had altered over the previous century and a half. He realized that not only had it happened during the period mentioned earlier, but it was happening all the time
136
What were the seven objects that wandered through the skies?
The Sun, the Moon, Mercury, Venus, Mars, Jupiter and Saturn
137
Which culture does Astrology trace it's roots too?
Astrology started in Babylonia about two and a half millenia ago. Eventually, the Babylonian culture was absorbed by the Greeks, and eventually influenced the entire Western world aswell as Asia
138
What does it mean to ask someone what their sign is, astronomically speaking?
Whenever someone ask's you your 'sign', they are actually asking for your 'sun sign', meaning which zodiac sign the Sun was in the moment you were born
139
Why wouldn't your sign today be the same as it was 1000 years ago?
Since more than 2000 years had passed since the signs received their names from constellations, so the real constellations are out of step
For example, the sign of Aries now occupies the constellation of Pisces
140
What was the 'Celestial Realm?'
Known to be the realm of the divine and spiritual
141
What was the Copernican Revolution?
| What did Copernicus do?
Nicolaus Copernicus reappraised the previous models of astronomy, and thus revived the Heliocentric Model.
142
What was Copernicus' Heliocentric Model?
Copernicus proposed a Sun-centred model that determines the layout of the solar system, essentially claiming that all planets (including Earth) orbited the Sun, and that the Moon was the only planet to orbit Earth.
143
Compare Ptolemaic, Copernican, and Tychonic models of the solar system
Ptolemy's model: Claimed that planets moved in a small circle, and that same circle will move around a big one
Copernican's model: Claimed that the sun was in the centre, and that all other planets circled around it
Tychonic's model: Tycho's model was a Geo-Helio hybrid, as it still thought that Earth was at the centre of the Solar system, but recognized that other planets orbitted the Sun
144
How did Copernicus, Tycho, and Kepler contribute to our shift from a geocentric, to heliocentric view of the Universe?
Copernicus: Revived the Heliocentric model, proposing a sun-centred model
Tycho: Was a Geo-Helio hybrid, but instead put planet Earth in the middle instead of the Sun
Kepler: Discovered that the orbit of planets were not circular, but instead ellipses, thus bringing forth the 'Kepler's Laws of Planetary Motion'
145
What were Kepler's Laws of Planetary Motion?
| There are 3
First law: The orbit of each planet around the Sun is an ellipse, with the Sun at one focus
Second law: As the planet moves around the orbit, it sweeps out equal areas in equal times, meaning that a planet will travel faster when its closer to the Sun, and moves slower when farther from the Sun
Third law: More distant planets orbit the Sun at slower average speeds, obeying the relationship
p2 = a3
p = orbital period in years
a = average distance from the Sun in au
146
How did Galileo contribute to our understanding of the Universe?
He challenged the Copernican views, as well as their models
147
What did Galileo discover with the Telescope?
Being one of the first to actively use the telescope, he discovered that Venus had phases, similarily to the Moon
148
What were the three objections rooted in the Aristotelian views?
| There are 3
1. Earth cannot be moving because objects in the air would be left behind
2. Noncircular orbits are not 'perfect' as heavens should be
3. If Earth were really orbiting the Sun, we should detect stellar parallax
149
How did Galileo overcome the first idea (the nature of motion)
Galileo showed that objects in air would stay with a moving Earth. He showed that objects will continue to stay in motion, unless an external force acts to slow them down
150
How did Galileo overcome the second idea (heavenly perfection)
| There were 2 main ideas
1. Even though Tycho already challenged this idea through his observations, Galileo used a telescope and found Mountains and valleys on the Moon, therefore proving that it is not a perfect sphere
2. Galileo then used a telescope on the sun, and realized that there were 'sunspots' on the sun, thus being 'imperfections'
151
How did Galileo prove that the Ptolemy model was incorrect?
When Galileo observed that Venus had phases, it showed that Venus revolved around the Sun, instead of revolving around the Earth as the Ptolemy model originally indicated
152
What was the *Principia*, and what type of topics did it cover?
| Theres 6 topics and more covered
The *Principia* basically used all the ideas, rules, and observations from Copernicus, Tycho, Kepler. Galileo (and others) and essentially compressed into one conceptual framework. The *Principia* covered many topics such as:
1. How gravity works
2. Relative masses of known planets
3. Explains the moons orbit
4. Identifies the Earth's shape (oblate spheroid)
5. Explains tides
6. Explained precession of equinoxes
and many more...
153
What were Newton's Laws of Motion?
| There are 3
1. Every object will continue to be in a state of rest or move at a constant speed in a straight line unless it is compelled to change by an outside force
2. The change of motion of a body is proportional to and in the direction of the force acting on it
3. For every action, there is an equal and opposite reaction
154
What is the Newton's First Law of Motion? (more detailed)
Objects will be in a state of rest, or move at a constant speed in a straight line unless it is compelled to change by an outside force
Is sometimes called the *law of inertia*, where inertia is the measure of an object's tendency to keep doing what it's doing, formally known as the **law of conservation of momentum**
Is represented by the equation p = m x v
p = momentum
m = mass
v = velocity
155
What is Newton's Second Law of Motion?
(more detailed)
The change of motion of a body is proportional to and in the direction of the force acting on it
Represented in an equation F = m x a
F = force
m = mass
a = acceleration
156
What is Newton's Third Law of Motion? (more detailed)
For every action, there must be an equal and opposite reaction. Meaning that the action of two bodies upon each other are always equal and act in opposite reactions
If someone leaped of the boat to the left, the boat would go to the right
157
Define Mass, Volume, and Density
Mass: A measure of the amount of material within an object
Volume: Volume is a measure of how much physical space an object takes up
Density: A measure of how tightly packed the material is
158
What's the difference between weight and mass?
Mass is a measure of the amount of material within an object, whereas the weight is a measure of how hard the force of gravity is pulling on that mass
159
What was Newton's Universal Law of Gravitation?
Newton realized that the same force that holds us down on Earth, could be the same force that causes the Moon to orbit us. Essentially saying that gravity is a force that acts upon everywhere
160
What were the different types of orbits possible within Newton's *Principia?*
| There are 5
1. The cannonball simply hits the ground after fired from a certain distance
2. Upon adding more gunpower, the cannonball covers more distance until it eventually falls
3. Adding more gunpowder, the cannonball would orbit the Earth in a circular motion, and would not hit the ground
4. Adding more gunpowder, the cannonball will exhibit a elliptical motion around the Earth
5. Eventually, you give it so much gunpowder that the cannonball will eventually shoot the cannonball into space
161
How does Kepler's 3rd law of planetary motion help us determine the mass of something in space?
Recall that Kepler's third law indicated that more distant planets orbitted the Sun at slower average speeds. By knowing the orbital period, and the semimajor axis, you can calculate the mass of a system
162
What determines the strength of gravity?
| In other words, what variables affect this?
the d variable, representing *distance* can affect the strength of gravity, as increasing this value will cause it to be weaker, while decreasing this value will cause it to be stronger.
Additionally, M1, and M2 can also change the force of gravity as if it increases, force of gravity will increase, if it decreases however, the force of gravity will decrease.
Know that the formula to calculate gravity is
FG = G(M1M2)/d2
163
What is the 'inverse square' law? How does it work?
Similar to FG = G(M1M2)/d2, the Inverse Square Law showed how much stronger/weaker gravity would be if the distance was ever changed. The way the Inverse Square Law worked was that if you were to increase seperation between two objects by some amount, the force of gravity would decrease by the square of the separation change.
For example, increasing seperation by 5x farther makes the gravity 25x weaker. Decreasing seperation by 5x closer makes gravity 25x stronger.
164
What assumptions did Copernicus make about the heavenly bodies that were incorrect?
Assumed that the motions of the heavenly bodies were made of combinations of uniform circular motions
165
What is Newton's version of Kepler's Third Law?
M1 + M2 = (4π2/G)(a3/p2)
p = orbital period
a = average orbital distance (between centres)
(M1+M2) = sum of object masses
Essentially if you know both p and a, you can find the mass of an object in outer space. For example, to find Jupiter's mass, find an object that orbit's it, and determine how long it takes to orbit that object, and also determine how far that object is to Jupiter itself.
166
Why did experimentation not carry much weight in Copernicus' time?
People followed a long philosophical tradition where pure human thought combined with divine revelation represented the path to truth. Aristotle in particular had more convincing arguments
167
What is the definition of acceleration
The changing of speed or direction of motion
168
What did Galileo observe with his new telescope?
After creating his telescope, he turned it to the heavens, where he saw some nebulous blurs resolved into many stars, which was the Milky Way
169
What is an orbit?
The path of an object through space is called its orbit
170
What are the four types of conic sections?
Circle, Ellipse, Parabola, Hyperbola
171
What is an ellipse? And what are an Ellipse's foci?
An ellipse is shape that is similar to a flattened circle
The sum of the distance from two special points inside the ellipse to any point on the ellipse is always the same. These two points inside the ellipse are called its foci (in other words, focus)
172
What is an ellipse's major axis? and what is it's semimajor axis?
Major axis: The widest diameter in the ellipse
Semimajor axis: Half the distance from the center of the ellipse to one end
173
How would I create an Ellipse?
Insert two tacks into a paper, and wrap a string on those tacks. Both tacks represent the focus of the ellipse (foci). Stretch the string tight with a pencil, then use the pencil to draw around the tacks. This creates an equal sizing ellipse
174
How does the position of two focus points on an ellipse affect the size/shape/ellipticity of the ellipse?
If you move the focus points closer together, the size, shape, and ellipticity will decrease. However if you increase the focus points distance apart, the size, shape, and ellipticity will increase
175
What is eccentricity?
Basically, it is how compressed the ellipse looks
Essentially, increasing eccentricity makes it so that the ellipse becomes more stretched apart
176
What is orbital speed
A term that describes how fast an object moves through it's ellipse
177
What is momentum?
Defined as an object's mass times its velocity
178
What is *angular momentum?*
A measure of the rotation of a body as it revolves around a fixed point. Defined as the product of its mass, velocity, and distance from the fixed point at which it revolves
179
What is the *Conservation of angular momentum?*
If a planet were to approach the Sun on its elliptical orbit and the distance to the spin center decreases, the planet speeds up to conserve the angular momentum
180
How do figure skaters demonstrate the Conservation of angular momentum?
Figure skaters bring in their arms and legs to spin more rapidly, and will extend their arms and legs in order to slow down
181
Why do astronauts aboard the ISS float, even if they're being pulled by Earth's gravity
It is because they are in free fall, and accelerate at the same rate as everything around them, including their spacecraft. Because of this, the astronauts experience no additional forces. It is also because they are floating *around* Earth, not towards it
182
Why is light considered the key to astronomy?
Because light is the primary way we learn about the Universe
183
What terms do we use for when light and matter interact?
| There are 5
1. Emission
2. Absorption
3. Transmission
4. Reflection
5. Scatter
184
What are Atoms, what particles are they made of?
Atoms are basic building blocks of nature, and are made of three particles:
Protons (+ charge)
Neutrons (0 charge)
Electrons (- charge)
185
What happens when charged particles move?
Whenever charged particles move due to attraction, repulsion and such, it creates both electric and magnetic fields
186
What is the difference between a contact and a non-contact force?
| Provide three examples for both
Contact Forces: Requires contact. This includes: Friction, Air Resistance, and Tension
Non-Contact Forces: Does not require contact. This includes: Gravity, Electric, and Magnetic
187
How are Electric and Magnetic Fields related to each other?
This is because both fields are fundamentally connected to each other. Once one of them is produced, it is possible for them to continuously trigger each other
188
What is light?
Light, and other forms of radiation is a combination of electric and magnetic fields, which are called **Electromagnetic Radiation**
189
What is a wave? What speed do light waves travel?
A wave is a pattern of motion that can carry energy without carrying matter along with it. Light waves only travel at one speed with is approximately 300,000 km/s (*the speed of light*)
190
What are the differences of waves in water/sound waves, and Electromagnetic waves?
Wave: Requires a medium, and travel at different speeds
Electromagnetic Waves: No medium is required, and travel at only one speed
191
How can waves communicate information?
We can distinguish different waves by their wavelength. In terms of visible light, waves can communicate colour
192
What is a wavelength? and how is it related to colour?
Wavelength: Is the distance between two crests, or two troughs
It relates to colour because colours on the ROYGBIV spectrum show that colours on the red side have a longer wavelength, and proceeds to get shorter as it goes right
193
What is frequency?
A frequency is the number of wave cycles that pass by per second. Typically, lower frequencies have longer wavelengths, and higher frequencies have shorter wavelengths. Frequencies can also be represented by *hertz* (Hz)
194
How does a wave communicate information?
| What is Crest, Trough, Wavelength, and Amplitude?
Crest: The height above 'zero' (maximum)
Trough: The depth below 'zero' (minimum)
Wavelength: Distance between two crests, or two troughs
Amplitude: Measuring the height/depth of the wave
195
What is the Inverse Square Law?
| In terms of light
As light travels further, the concentration of electromagnetic radiation decreases by a square of how far it travels and vice versa
196
How are wavelength, frequency, and energy of a wave interrelated?
Determining the energy of a wave can be determined by the wavelength, and the frequency
197
What is the Electromagnetic Spectrum?
A spectrum that shows all types of Electromagnetic Radiation, as well as their wavelength + frequencies
198
What are all types of Electromagnetic Radiation? (From lowest energy to highest)
| 7 different types
1. Radio
**Wavelength**: Greater than 1 meter
**Frequency**: Less than 108 Hz
**Energy**: Lowest
2. Microwaves
**Wavelength**: Length is greater than 0.001 m but less than 1 m
**Frequency**: Greater than 108 Hz, but less than 1011
**Energy**: Low
3. Infrared waves
**Wavelength**: Length is greater than 7x10-7 m but less than 0.001 m
**Frequency**: Greater than 1011 Hz but less than 1014
**Energy**: Low-medium
4. Visible light
**Wavelength**: Length is greater than 4x10-7 but less than 7x10-7
**Frequency**: Greater than 4x1014 Hz, but less than 7x1014 Hz
**Energy**: Medium
5. Ultraviolet Light
**Wavelength**: Length is greater than 2x10-8 but is less than 4x10-7
**Frequency**: Greater than 1014 Hz but less than 1016 Hz
**Energy**: Medium-high
6. X-ray light
**Wavelength**: Length is greater than 1x10-11 but is less than 2x108
**Frequency**: Greater than 1016 Hz but is less than 1018 Hz
**Energy**: High
7. Gamma Rays
**Wavelength**: Length is less than 1x10-11
**Frequency**: Is greater than 1018 Hz
**Energy**: Very high
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What are the different uses for both human uses and cosmic sources for all 7 types of electromagnetic radiation?
1. Radio
Humans: RADAR, AM&FM radio, TV, communications
Cosmic: Supernova remnants, pulsars, cold gas, black hole accretion disks
2. Microwaves
Humans: Short-wave communcations, microwave ovens
Cosmic: Active galaxies, pulsars, the cosmic microwave background (CMB)
3. Infrared waves
Humans: Humans ourselves emit EM radiation
Cosmic: Cool clouds of gas and dust, planets, and moons
4. Visible light
Humans: Light bulbs and many other things
Cosmic: Stars
5. Ultraviolet Light
Humans: Industrial processes, medical practices, and dental practices
Cosmic: Supernova remnants, very hot stars
6. X-ray light
Human: Imaging bones/teeth
Cosmic: Gas in clusters of galaxies, supernova remnants, solar corona
7. Gamma Rays
Human: Radioactive elements
Cosmic: Produced in nuclear reactions; which require very high-energy processes
200
Which electromagnetic radiation can travel through our atmosphere?
| There are 4
Radio, Microwave, Infrared, and Visible waves are able to travel through the atmosphere
201
What determines the type of electromagnetic radiation emitted by dense astronomical objects? and Why?
Temperature determines the type of electromagnetic radiation, as temperature is the measure of the amount of *energy* the particles have
Large energy = Particles move/vibrate fast
Small energy = Particles move/vibrate slow
202
What are the three different units of temperature?
Fahrenheit: (F)
Celsius or Centigrade: (C)
Kelvin: (K)
However, Kelvin is mostly used in Astronomy because the temperature scale is measured from 'absolute' zero, therefore there are no negative temperatures
203
How does temperature affect the strength, and type of radiation an astronomical object creates?
| There are two results
1. Hotter objects emit more light at all wavelengths
2. The higher the temperature, the shorter the wavelength at which maximum intensity is emitted
204
How does energy of light scale with its frequency?
The higher the frequency, the higher the energy
205
What type of light is immediately 'bluer' than visible light on the electromagnetic spectrum?
Ultraviolet light
206
What is relflection and refraction?
Reflection: The reflected beam can be calculate accurately from the knowledge of the reflecting surface.
Refraction: Light is bent when it passes from one transparent medium to another. (ie, air to glass, glass to water, space to air)
207
What is Dispersion?
Is how much light bends depending on its wavelength and the materials properties. This was present in Newton's rainbow experiment
208
What is a Spectrum, and what is Spectroscopy?
Spectrum: Referred to as a rainbow of light
Spectrometer: An instrument used to create such a spectrum
209
What is a Continous Spectrum and what causes it?
A continous spectrum is a continous band of light from the red-end to the blue-end of the visible spectrum. Caused by a source of light that has temperature
210
What is an absorption line spectrum?
Is similar to a continuous spectrum, but has dark lines throughout the spectrum, indicating that light was being 'absorbed' by something
211
What is an emission line spectrum?
An emission line spectrum is a spectrum that only shows emission lines created by a gas emitting light in specific narrow wavelengths
212
What is the connection between the emission line spectrum, and the absorption line spectrum?
The absent black lines present in the absorption line spectrum, matched the emission lines from the emission line spectrum
213
What is a chemical fingerprint? and what can they be used for?
Each type of element has a unique set of spectral patterns of emission/absorption lines. The unique patterns are called a chemical fingerprint, and can be used to identify something by simply collecting its light
214
What is a simple view of the structure of an Atom
An atom has a dense center made of protons and neutrons, and are surrounded by orbits where the electrons are
215
How does the amount of protons, neutrons and electrons affect an atom?
Protons: # of protons determines an atom's # of electrons and it's tytpe of element
Neutrons: Doesn't change the element, but can change how the element behaves
216
What are Isotopes?
Isotopes are basically same elements with differing neutron amount
217
What are energy levels?
The orbit of an electron can determine its energy
218
What happens to an electron's energy once it changes energy levels?
Whenever electrons move/jump from one energy level to another, it requires a change in their energy
Electrons that go to a higher energy level must gain energy
Electrons that go from a higher energy level to a lower level must lose that energy
219
What is a Ground State, and Excited State?
Ground State: An electron in the lowest orbital shell
Excited State: Electrons in a higher energy level
220
What happens when an electron absorbs a photon
If the photon is the same exact energy/wavelength it needs for the electron to get excited, it'll jump to a higher shell
221
What happens when an electron emits a photon
When an excited electron drops to a lower energy level, it emits a photon with the exact energy/wavelength to return to ground state
222
What is ionization?
Is when the electron escapes the atom entirely, after absorbing enough energy
223
Why do different elements create such different absorption/emission patterns?
And why do elements always have the same pattern?
Because each element takes a different amount of energy for an electron to jump from one orbit to another
Similarily, each element has the same pattern because of they all require a consistent amount of energy
224
What is the *Doppler Effect*
If the light source is in motion, relative to the observer, the wavelength of the light can appear to change
225
What is the meaning of Red-shift and Blue-shift?
Redshift: A redshift is when the lightsource is moving away from the person, as the light will appear redder (longer wavelength)
Blueshift: A blueshift is when the lightsource is moving towards the person, as the light will appear bluer (shorter wavelength)
226
What happens to redshift and blueshift if an object: moves towards us, moves away from us, diagonally away, diagonally towards, or moving across line of sight?
Moves towards us: A blueshift is caused (shorter wavelength)
Moves away from us: A redshift is caused (longer wavelength)
Moves diagonally closer: A slower blueshift is caused, but eventually the speed of the Doppler effect cannot be seen
Moves diagonally away: A slower redshift is caused, but eventually the speed of the Doppler effect cannot be seen
Across our line of sight: No shift will be seen at all
227
How does speed affect the doppler affect? Give an example of this
If an object were to either move quickly towards/away from us, the location on their spectrum can shift left to right
Regular redshift: Spectrum lines shift right
A fast redshift: Causes the lines on the spectrum to shift even more right
Regular blueshift: Spectrum lines shift left
A fast blueshift: Causes the lines on the spectrum to shift left even more
228
What does the Doppler effect mean for astronomy?
| There are 2 answers
1. We can determine if something is moving towards/away from us
2. We can measure how fast it is moving towards us or away from us
229
What is the System for Measuring Radiation?
| Has three basic components
1. A telescope: Collects EM radiation
2. A filter: Sorts wavelengths of light as needed
3. A detector: Senses the light and permenantly records it
230
What is the basic principle that telescopes operate on?
A telescope will collect as much light as possible from an astronomical sources, and will focus all that light to a single point
231
Formation of an image by a lens or mirror
The main goal is to focus parallel light rays to a single point, which makes it possible to form an image of an object
232
What is a Refracting Telescope?
A Refracting Telescope uses lens to focus light from a large collecting area to a single point
233
What is a Reflecting Telescope?
Reflecting Telescopes use mirrors to focus light from a large collecting area to a single point
234
How does the size of the aperture make a telescope more or less effective?
| There are 2 reasons
The larger an aperture, the more effective the telescope will be because:
1. This means a larger collecting area, which means more light is captured
2. You can increase your angular resolution
235
What are the problems with refracting telescopes?
| There are 2 problems
1. Lenses can only be so big before it begins to deform on its own
2. Remember that light can be bent when it passes through a transparent medium
236
What do you need to consider when choosing a site for an observatory?
| There are 3 things
1. Clear skies
2. Dark skies
3. Calm skies
237
What is the difference between Imaging, and Spectroscopy
Imaging: Basically taking a image of the sky
Spectroscopy: Is used to acquire brightnesses, and colours on a spectrum. Essentially you are finding the colour of something from light
238
How did different designs change based on the type of electromagnetic radiation they are observing
Longer wavelengths like radio have larger telescopes that are used for observation. As the wavelength becomes smaller and the frequency becomes higher, telescopes start to become more smaller and compact. Eventually, the design for X-ray's needed to change as x-rays could not be observed with mirrors anymore, (because x-rays cannot be reflected on mirrors) and are instead built with shelves where the light of the x-ray becomes more slowly focused
239
How does Earth's atmosphere affect astronomical observations? and how was this solved?
| There are 3
1. There is light pollution
2. Turbelence causes twinkling, which blurs images
3. Atmosphere ends up absorbing most of EM spectrum, including all UV and X-ray to most infrared
Astronomers solved this by sending telescopes in space because there is no pollution, and nothing to absorb any sort of light
240
What are Adaptive Optics?
Are when the mirror shape rapidly changes in order to compensate for atmospheric turbulence
241
What are other things we can observe from space?
| There are three things
1. Neutrinos: Tiny subatomic particles produced in fusion reactions
2. Cosmic rays: High-energy subatomic particles
3. Gravitational waves: ripples in the fabric of space time
242
What is the meaning of "Radiation" in Astronomical context?
A general term for waves that radiate outward from a source
243
How does Maxwell's Theory of Electromagnetism produce a magnetic field?
Maxwell's theory states that stationary electric charges produce electric fields, whereas moving electric charges produce **Magnetic fields**
244
What did Maxwell discover when electric charges were oscillating?
Discovered that the resulting pattern of electric and magnetic fields would spread out and travel rapidly through space
245
What does the term "blackbody" mean?
Is an idealized object that absorbs all electromagnetic energy that falls onto it
246
How does the temperature of a star determine the wavelength of peak intensity?
The higher the temperature, the shorter the wavelength at which the peak amount of energy is radiated, and vice versa
247
What is an *alpha particle*
Are helium atoms that have loss their electrons and thus are positively charged
248
What is *Deuterium?*
Is an isotope of hydrogen, as it has 1 more neutron than hydrogen
249
Explain the three types of Spectra's
Continuous: When we see a lightbulb, or another source of continuous radiation, all colours are present
Absorption: When the continuous spectrum goes through a thinner gas cloud, the cloud atoms produce absoption lines in the continuous spectrum
Emission: When the excited gas cloud is seen without the continuous source behind it, the atoms produce emission lines
250
What is Radial velocity?
Is a term that describes the motion towards or away from the observer
251
What is **Chromatic abberation?**
Optical properties of transparent materials may change the wavelengths a little bit, this distortion is also known as *chromatic abberation*
252
What is the Solar System?
A collection of objects that orbit a single star we call the Sun. These objects include the planets, their moons and rings, asteroids, comets, dust, etc
253
What is the Solar System Census?
| There are 6 objects
1. 1 Mid-sized main sequence star
2. 8 planets
3. 5 dwarf planets
4. 200+ moons
5. 1,308,871+ asteroids
6. 3800+ comets
254
What is the "real view" of the solar system?
| There are 3 points
1. Planets occupy the same 'plane', therefore the Solar System is flat
2. The planets (and most other things) all orbit the Sun in the same direction
3. Each planet rotates on its own axis, most of the time, this is in the same direction as their orbit around the Sun
255
What is the Solar System Mass Budget?
The Sun takes up most mass of our solar system as it has a total mass percentage of 99.90 percent, with Jupiter being 0.10 and other planets and objects being 0.04
256
What is the Sun's characteristics?
| There are 4
1. A star, which is brighter than about 80% of star in the Milky Way
2. It is 1,392,700 km wide
3. Surface temperature is about 5800 K
4. Core's temperature is greater than 10,000,000 K
257
What is the colour of the Sun?
The Sun is White
258
What are the four terrestrial planets, and what are their characteristics?
| There are three characteristics
Earth, Mars, Venus, and Mercury
1. Made of mostly rock and metal
2. Have solid surfaces
3. Have records of their geological history (mountains, volcanoes, craters, and erosion)
259
What are the Most common rock and metal group?
Rock = Sillicates (e.g,
quartz)
Metal = Iron (Fe)
260
What are the terrestrial Planets made of?
| Has rock and metal
2/3 silicates and 1/3 iron
261
What are characteristics of the Asteroid?
| There are four characteristics
1. Sometimes referred as a 'minor planet'
2. Are small
3. Mostly rocky/metallic
4. Range in size from 1 meter to hundreds of kilometres
262
What is the Asteroid Belt?
Are circular orbits of asteroids within the inner solar system, between the orbits of Jupiter and Mars
263
What are the four largest asteroids in the Asteroid Belt?
1. Ceres (939 km)
2. Vesta (525 km)
3. Pallas (512 km)
4. Hygiea (434 km)
264
What are the characteristrics of Jovian Planets?
| There are four characteristics
1. Large world
2. Comprised mostly of lighter ices, liquids, and gas
3. No solid surface to stand on (vast spherical oceans)
4. Small dense cores
265
What are Jovian Planets mostly made of?
Are 75% Hydrogen and 25% Helium
266
What are the four Jovian planets?
Jupiter, Saturn, Uranus, and Neptune
267
What are the Kuiper Belt Objects (KBOs) or Trans Neptunian Objects (TNOs)?
Are small mostly icy/rocky objects that can range in size from 10s of meters to over 2000 kilometres
268
Where does the Kuiper Belt exist?
Exists beyond Neptune's orbit
269
How old is the Solar System?
The Sun and all the objects formed about 4.5 billion years ago
270
What is a Half-life?
The time it takes for about half of the nuclei to decay into smaller nuclei
271
# Half-Life example:
If you had 1 kg of pure element A, how much of element A would you have after 100 years?
500 g
272
How old was the oldest mineral ever recorded?
4.404 billion years old
273
What are the characteristics of the Earth?
| There are eight characteristics
1. Average distance from the Sun: 1.00 au
2. 1 Moon
3. Atmosphere is 79% N2, 21% O2
4. Radius is 6,378 km
5. Mass is 1.00 M
6. Density: 5.52 g/cm3
7. Average surface temperature is 290 K
8. Range's in temperature between -89oC and 54oC
274
What does it mean that the Earth is Differentiated?
The word *Differentiation* describes the process of planetary material separating by density
Lower dense material rises to the surface as the higher dense material sinks to centre
275
What is the Earth's Magnetosphere?
The Earth behaves like a large magnet, as the poles of the magnet are approximately aligned with the Earth's North-South axis
276
What is the liquid dynamo in the Earth's Magnetosphere?
The Earth's outer core is molten, meaning that it is able to flow as a liquid. Because the outer core is liquid, it helps produce the Earth's magnetic field. The liquid outer core also has convection currents within it
277
What are the characteristics of the Moon?
| There are 9
1. Average distance from Earth is 384,400 kms
2. No atmosphere
3. No magnetic field
4. Has a 1,737 km radius
5. Mass is 0.01 M
6. Has a 3.34 g/cm3 density
7. Temperature is in the range of -180oC to 120oC
8. One full orbit takes 27.3 days
9. One full Lunation takes 29.5 days
278
How was the Moon formed?
It was hypothesized that the Moon was born from a giant impact shortly after the planets in the Solar System were formed
279
What is the characteristics of Mercury?
| There are 9
1. Average distance from the Sun is 0.39 au (therefore the closest)
2. No Moons
3. No atmosphere
4. has a weak magnetic field
5. Its radius is 2440 km
6. Has a mass of 0.055 M
7. Density is 5.42 g/cm3
8. Made of metal and rock, and has a large iron core
9. Temp is in the range of -180oC to 430oC
280
Why does Mercury have a larger iron core than Earth?
Very likely that Mercury's mantel and crust were much larger, but were stripped away through repeated impacts
281
What are the characteristics of Venus?
| There are 8
1. Average distance from the Sun is 0.72 au
2. No Moons
3. Atmosphere is 95% CO2, and is 100x thicker than Earth
4. No magnetic field
5. Radius is 6051 km
6. Mass is 0.82 M
7. Density is 5.24 g/cm3
8. Temp range is -438oC to 482oC (which makes it the hottest planet)
282
What is the Greenhouse effect on Venus?
The greenhouse effect on Venus created a very thick and hot atmosphere, which is primarily made of CO2, as the surface is currently obscured by thick clouds
283
What are the characteristics of Mars
| There are 8
1. Average distance from the sun is 1.52
2. Has 2 Moons which are 25 km and 15 km in size
3. Has an atmosphere of 95% CO2, and is 100x thinner than Earth's
4. Has a possible weak magnetic field
5. Radius is 3397 km
6. Mass is 0.11 M
7. Density is 3.93
8. Temperature is in the range of -153oC to 20oC
284
Why was it claimed that Mars had water?
Many missions to Mars found evidence within the rock of mineral deposits and other water deposition features that most accept as conclusive proof that water once flowed on Mars approximately 3 billion years ago
285
Which planets have a differentiated inner solar system?
All 5 Terrestrial planets (Earth, Mercury, Venus, Mars, and the Moon) have a mostly metal core with a silicate crust
286
Why does the Asteroid Belt exist?
Because of Jupiter, as Jupiter has a gravitational influence, it gravitationally shepherded the asteroid belt into existence
287
What are the characteristics of Jupiter?
| There are 9 characteristics
1. Average distance from the Sun is 5.20 au
2. Has 95 Moons
3. Has a huge magnetic field
4. Has a 71,492 km radius
5. Mass is 318 M
6. Density is 1.33 g/cm3
7. Cloudtop temp = 125 K
8. Surface is mostly H/He, and is not solid
9. Has rings
288
What are the Galilean Moons?
| There are 4
Are Jupiters Moons
Io: Active volcanoes all over
Europa: Possible subsurface ocean
Ganymede: Largest moon in solar system
Callisto: A large, cratered "ice ball"
289
What are the characteristics of Saturn?
| There are 10
1. Average distance from the Sun is 9.54 au
2. Has 146 Moons
3. Huge Magnetic Field
4. 60,268 km radius
5. Mass is 95.2 M
6. Is Giant and Gaseous like Jupiter
7. Has noticeable rings
8. Density is 0.70 g/cm3
9. Cloudtop temp = 125K
10. Mostly H/He as it has no solid surface
290
What are Saturn's rings made of?
Are not solid, and are made of countless small chunks of mostly Ice, which orbit like a tiny Moon
291
What are Saturn's complex Moons?
| There are 2
Enceladus: Has geysers shooting water into space
Titan: The only moon with a dense atmosphere, and the only other object that has liquids on its surface (liquid is methane and ethane)
292
What is Uranus characteristics?
| There are 9
1. Average distance from the sun is 19.52 au
2. Has 27 Moons
3. Huge Magnetic Field
4. 25,559 km radius
5. Mass is 14.5 M
6. Density is 1.32 g/cm3
7. Cloudtop temp T = 60 K
8. Made of H/He gas and hydrogen compounds (H2O, NH3, and CH4)
9. Has an extreme axis tilt (98o
293
What are Neptune's characteristics?
| There are 8
1. Average distance from the Sun is 30.1 au
2. Has 14 Moons
3. Huge magnetic field
4. Radius is 24,764 km
5. Has a 17.1 M
6. Density is 1.64 g/cm3
7. Cloudtop temp = 60 K
8. Made of H/He gas and hydrogen compounds (H2O, NH3, CH4)
294
What is one thing that all Jovian planets have?
They all have planetary rings
295
What are the characteristics of Pluto and Charon?
| There are 6
1. Average distance from the Sun is 39.1 au
2. Has 5 Moons
3. Radius is 1185 km
4. Has a mass of 0.0022 M
5. Density is 1.9 g/cm3
6. Average surface temperature is 44 K
296
What is the Oort Cloud?
Extends to possibly 100,000 au away from the Sun. It is known to be one of the farthest objects still gravitationally bound to the Sun
297
What did the Astronomical Union Decide for Pluto?
It was demoted to a "Dwarf Planet"
298
What were the "Original Planets"
| There are 7 planets
1. Moon
2. Mercury
3. Venus
4. Sun
5. Mars
6. Jupiter
7. Saturn
At the time, Earth was not a planet, and the Moon and Sun were. The 7 planets (wanderers) had religious association. The definition of a planet remained unchanged until the Copernicus revolution
299
How did Copernicus define what a planet is?
An object that *orbits* the Sun
300
What was the *Titius-Bode Law*
A law developed by Titius and Bode that noticed there was a pattern to the spacing of the planets. All distances were discovered except for 2.8 au
301
What were the Celestial Police?
Inspired by the discovery of Uranus, which had a goal to find the missing object between Mars and Jupiter (2.8 au)
302
Who discovered of Ceres? and what did it become of it?
Italian astronomer Giuseppe Piazzi discovered Ceres at 2.8 au, which was then designated as the 8th planet in the Solar System
303
What was the discovery of Pallas?
German Astronomer (Olbers Pallas) found Pallas at 2.8 au, which was the same as Ceres
304
What was Herschel's Proposal?
Proposed that the objects discovered (Ceres, Pallas, Juno, and Vesta) must be reclassified as 'asteroids' due to their appearance
305
What happened to the Titius-Bode Law after the discovery of Neptune?
The au of Neptune was not the same as listed in Titius-Bode Law, therefore deeming that the Titius-Bode Law is not **REAL**
306
Who discovered Pluto?
Clyde Tobaugh in 1930, discovered a small object beyond Neptune, which was Pluto
It was then designated as the 9th planet
307
What did the International Astronomical Union decide?
They decided a new official definition of a planet with 3 Criterias
308
What was the official definition of a planet?
| There are 3
A planet must
1. Orbit around the sun
2. Must be spherical (excludes most asteroids, comets, etc)
3. Must have cleared the debris in its orbit (excludes all asteroids, and KBOs, including Ceres and Pluto
309
What is the definition of a Dwarf planet?
| There are 4
1. Orbits around the Sun
2. Is spherical
3. Has debris in its orbit
4. Not a satelite
310
What are the 5 official Dwarf Planets?
1. Ceres
2. Pluto
3. Eris
4. Haumea
5. Makemake
311
What was the observations that made the Solar System look this way?
| There are 8 observations
1. Most of the mass is in the Sun (99.8%)
2. Planets and most other objects are co-planar (meaning all objects are on the same orbital plane)
3. All planets and most other objects are co-directional (meaning all objects move in the same direction that is counter-clockwise)
4. Planetary orbits are roughly circular
5. Differing planetary composition and mass which varies with distance
6. Planets spin in the same direction
7. Planets have similar axial tilts
8. Cratering rate was higher in the past
312
What is the Nebular Theory Model?
| There are 4 steps
1. The Solar Nebula (large cloud of gas and dust) Contracts
2. As the Nebula shrinks, its motion causes it to flatten
3. The nebula is a disk of matter with a concentration near the center
4. Formation of the protoson. Solid particles will condense as the nebula cools, which gives rise to the planetesimals which are the building blocks of the planets
313
As the cloud spins, it flattens, why does this happen?
| Two reasons
1. Spin rates are different at the poles vs the equator, which allow materials at poles to fall more easily towards the centre
2. Collisions
314
How did the Nebular Hypothesis explain the formation of a Planetary System? (Model)
| There are 4 reasons
Eventually, all matter had either
1. Fall to the star in the centre
2. Fall into a growing planetesimal (which becomes a planet)
3. Kicked out of the system completely
4. Is scattered or shepherded, or influenced into a belt of some kind
315
What was the result after testing the Nebular Theory model?
The model was successful, as it was all proven true
316
Which type of electromagnetic radiation travels the fastest in space?
None, as they all travel the same speed (speed of light)
317
What is the generic name for a group of planets, and other objects orbitting a star?
A star system
318
What is the astronomical unit? (au) and why is it used more preferably than km?
Astronomical Unit = the average distance between the Earth and the Sun
The reason why this unit is used is because distances using kilometres would be too big of a number
319
What is Radioactive decay?
Certain rocks have atomic nuclei that can split apart into smaller nuclei overtime
320
If the Sun was scaled down to an adult, how far would Earth be?
Earth is as far as one city block (150 m)
321
Besides radiometric dating, whats another way to find the age of the Solar System?
Counting the amount of craters
322
How does crater counting work?
More craters would mean that the object has been exposed to external forces for a long period of time
323
What are exoplanets?
Planets beyond the solar system
324
What is the Giant Impact Theory? and what was the evidence that supported this?
It was hypothesized that Earth was once hit by a large object, that caused Earth to eject objects into space, where it was then cooled and eventually became the Moon
The evidence was that there was large chunks of material orbiting the inner solar system at the time the Terrestrial planets were formed
325
What was the three hypothesis for the origin of the Moon?
1. The fission theory: the Moon was one part of Earth, but was seperated from it early in the history
2. The sister theory: the Moon formed together with Earth, as we believe many moons of the outer planets formed
3. The capture theory- the Moon formed elsewhere in the Solar System and was captured by Earth
326
What is unique about Mercury's orbit, in comparison to Earth?
Mercury is the closest to the sun, with an average distance of 0.39 AU, but it has high eccentricity of 0.206, which makes the actual distance of Mercury from 46 million kilometers from perihilion, to 70 million kilometers at aphelion
327
Does Mercury have plate tectonics?
No evidence of plate tectonics
328
What are scarps, how did they form after the craters, and what caused the scarps?
Scarps are cliffs that are more than a kilometer high and hundreds of kilometers long
It was formed after the craters because scarps can be seen cutting across the craters
The cause of these scarps could be during the point when the Mercury's crust shrank, wrinkling the crust
329
Why do we have Martian rock samples but no Mars samples?
There were already Martian rocks on Earth, which are meteorites
330
Are there volcanoes on Mars?
There is a volcano called the Tharsis volcanoes which were active 1.3 billion years ago, but are not active now
331
What are the axial tilts of all gas giants?
Jupiter: 3o so theres no seasons
Saturn: 27o which is perpendicular to its orbit and there are seasons
Neptune: 29o, which is nearly the same as Saturn, and experiences similar seasons but more slowly
Uranus: 98o which only orbits on one side
332
What are the internal composition of all Jovian planets?
Saturn and Jupiter are made mainly of hydrogen and helium, and Uranus and Neptune consist of carbon, nitrogen and oxygen
333
What is the basic structure of a comet?
Is a relatively small chunk of icy material
334
What is in a comets atmosphere?
Temporary gas and dust illuminated by sunlight
335
What is the orbit of a comet?
Goes around the Sun in a highly elliptical orbit
336
What is the difference between a short-period comet and a long-period comet?
Short-period comets: takes a century or two to orbit the sun
Long-period comets: Takes more than two hundred years to orbit the Sun
337
What is the distance of all planets from the Sun (closest to farthest)
| 8 planets
1. Mercury: 0.39 au
2. Venus: 0.72 au
3. Earth: 1.00 au
4. Mars: 1.52 au
5. Jupiter: 5.20 au
6. Saturn: 9.54 au
7. Uranus: 19.52 au
8. Neptune: 30.1 au
