Astronomy: The Sun (Unit 2) Flashcards
1
Q
Plasma Definition
A
A super-heated gas in which the particles are ionized
2
Q
Using technologies such as radio and X-ray astronomy, what have scientists been able to identify about the sun?
A
Scientists have been able to identify 6 layers that make up the sun, arranged from the center outward
3
Q
How do astronomers and astrophysicists estimate the arrangement and properties of the sun’s layers?
A
By combining known facts with theoretical models of the sun’s composition
4
Q
What are the first three layers of the sun?
A
The core, radiative zone, and convection zone
5
Q
What do the core, radiative zone, and convection zone form?
A
The sun’s inner structure
6
Q
What is the sun’s core?
A
The core is the innermost layer where the sun’s energy is produced by fusion reactions
7
Q
Where does the energy produced in the sun’s core travel to?
A
The energy from the core travels slowly through the dense 2nd layer, the radiative zone
8
Q
What happens in the convection zone of the sun?
A
In the 3rd layer, the convection zone, huge currents form and bubbles of hot plasma rise to the surface
9
Q
What are the sun’s outer three layers and what do they form?
A
The sun’s outer three layers — photosphere, chromosphere, and corona - form it’s atmosphere, the part we see from earth
10
Q
In which layer of the sun does visible light appear?
A
The photosphere
11
Q
What happens in the chromosphere?
A
The chromosphere, above the photosphere, emits a bright red glow as hydrogen burns off
12
Q
What does the corona of the sun do?
A
The corona, which surrounds the sun, helps release the sun’s heat into space
13
Q
When are the chromosphere and corona visible to us?
A
They are only visible to us during a total solar eclipse
14
Q
True or False: The temperatures of each of the layers of the sun varies
A
True
15
Q
How does the temperature of each layer of the sun vary?
A
The core is the hottest layer, with a temperature of 15.7 million K (28 million degrees Fahrenheit). Temperatures then decrease through the radiative and convection zones until they reach 5,800 K (10,000 degrees Fahrenheit) in the photosphere. Temperatures then rise again through the chromosphere and the corona. Scientists have yet to explain this pattern
16
Q
What is the core composed of?
A
Plasma
17
Q
How much of the sun’s radius does the radiative zone make up?
A
3/4
18
Q
What happens in the radiative zone?
A
In the radiative zone, energy from the core moves outward as thermal radiation, which bounces and zig-zags as it makes its way toward the surface
19
Q
What is the only visible layer of the sun from Earth without instruments?
A
The photosphere
20
Q
Which layer of the sun may have sun spots?
A
The photosphere
21
Q
What is the corona composed of?
A
Hot plasma
22
Q
Why is Earth the only planet known to have complex life?
A
Earth is the only planet known to have complex life, since it is in the sun’s habitable zone, where the right amount of energy from the sun is available
23
Q
About how old is the sun? How long with its remaining fuel last?
A
The sun is about 5 billion years old and has enough fuel to continue for another 5 billion years
24
Q
What is evidence for the sun’s energy transfer through its layers?
A
The energy enters Earth’s atmosphere, the plants then capture that energy, and then the animals receive then energy by eating the plants
25
What is the element that fuels the sun? What is in the center of this element’s atoms?
Hydrogen is the elements that fuels the sun, and the center of each hydrogen atom is its nucleus
26
When is most of the sun’s energy released?
Most of the energy that the sun emits is released when a strong gravitational attraction between hydrogen nuclei squeezes the nuclei together. With enough pressure, 4 hydrogen atoms can undergo nuclear fusion and form a helium atom, with the release of tremendous amounts of stored energy and gamma rays
27
Where does the rest of the energy emitted by the sun come from, when not from nuclear fusion reactions in hydrogen?
Fusion reactions involving other types of atoms
28
When the sun’s energy is released, through what regions does it travel?
It travels through the layers of the sun, through space, then to Earth
29
Nuclear Fusion Definition
A reaction in which atoms combine and release large amounts of energy
30
In nuclear fusion, where is energy released from?
Matter
31
Why does nuclear fusion occur in the core of the sun?
Because it is under so much pressure
32
What does the magnetosphere of earth do?
Charged particles, known as solar wind, travel outward from the sun in all directions, along with its energy, and the magnetosphere protects the atmosphere from being completely stripped away by solar wind while allowing the solar energy through
33
Solar energy radiates in all directions from the sun’s surface in the form of what?
Solar energy radiates in all directions from the sun’s surface as “electromagnetic radiation”. It travels at the speed of light and reaches earth’s surface in 8 minutes
34
True or False: the surface of the sun is a very active, high energy place
True
35
How is the sun’s release of radiation? Is it constant? Is it uniform?
The sun’s release of radiation is constant but not always uniform. When electrically charged gases move, they produce magnetic fields that are in constant motion. Depending on the motion of the magnetic fields, sporadic intense discharges of energy and matter occur.
36
Aurora Definition
Lights caused by interaction between particles from the sun and Earth’s atmosphere
37
True or False: The surface of the sun is full of energy, electrically charged particles, and magnetic fields
True
38
In some regions of the sun, with particularly strong magnetic fields, what happened as the magnetic fields get tangled?
In some regions, magnetic fields are particularly strong, and they can become twisted and tangled and produce solar flares that eject electromagnetic radiation into space
39
Coronal Mass Ejections occur near what other space event?
Massive bubbles of radiation and particles, called coronal mass ejections (CMEs), sometimes occur near solar flares. These bubbles explode and send energy and matter shooting into space
40
What can strong solar flares disturb on Earth?
Radio signals
41
What occurs on earth due to the interaction of charged particles from CMEs and Earth’s magnetic field?
CMEs emit charged particles, which are deflected by Earth’s magnetic field, causing auroras in the North and South poles
42
What is the order of energy release from the sun’s core to Earth?
Fusion, Radiation, Convection, Radiation
43
How did Galileo Galilei contribute to the study of sun spots?
Galileo Galilei measured and recorded the distance the black dots had moved since his last observation and calculated the rate they traveled across the sun
44
Was Galileo the first person to observe sunspots?
Galileo was not the 1st person to observe sunspots, but in 1610 he was the first to study them through a telescope and publish his findings
45
What was Galileo’s occupation?
He was an Italian physicist and astronomer
46
What did a contemporary scientists claim about sunspots? How did Galileo prove this wrong?
A contemporary scientists claimed that sunspots were planets, that were revolving close to the sun, but Galileo proved they were just apart of the sun’s surface, using his observations
47
The activities visible one the surface of the sun can be explained by what?
The sun’s magnetic properties
48
What is most of the matter in the universe made up of ?
Plasma
49
What is plasma?
Plasma is matter that has been heated to such a degree that some of the electrons are stripped off their atoms, resulting in a swirling mass of charged particles
50
True or False: A flow of electrically charged particles can generate a magnetic field
True
51
How does the sun rotate, due to it being made up plasma?
Since the sun is made of plasma, it does not rotate evenly: a point on the sun’s equator takes 25 days to make a full rotation, while a point on the poles takes up to 35 days
52
Due to its rotation, what is happening to the plasma within the sun?
It is constantly mixed and churned
53
What forms due to the differential rotation of the sun?
The differential rotation of plasma results in magnetic fields that ebb and flow. This system that produces the magnetic fields of the sun is called the solar dynamo, named after the device that generates electric current via a moving magnetic field
54
What happens when churning magnetic fields pop out of the sun’s surface?
Often, the churning magnetic fields pop out of the sun’s surface, acting like horseshoe magnets with a positive and a negative end. These regions, called sunspots, are slightly cooler that the rest of the sun’s surface, so they appear dark in comparison
55
Why are the sun’s features always changing?
Due to its complex magnetic field
56
How is the magnetic field of Earth?
Earth has a fairly stable magnetic field, with a single pair of magnetic poles
57
How is the magnetic field of Earth formed?
Earth’s magnetic field is created by movement of its liquid outer core around its solid inner core
58
True or False: The sun sometimes has more than one North Pole
True
59
How is the sun’s magnetic field created?
The sun’s magnetic field is created by movement in its outer layer, the convection zone
60
When the sun’s magnetic field gets tangled, what happens to convection?
When the sun’s magnetic field gets tangled, convection is inhibited, creating sunspots
61
How do sunspots appear as pairs?
Sunspots always appear in pairs; one with a magnetic North Pole and one with a magnetic South pole
62
What happens as the sun’s magnetic energy builds up?
When the sun’s magnetic energy builds up, it must release it as a solar flare. A solar flare is a sudden explosion of energy from the sun’s surface
63
What happens when the sun has billions of tons of matter to be released from its magnetic field?
When the sun has billions of tons of matter to be released from its magnetic field, a CME is sent out. CMEs can travel at millions of miles per hour
64
What do models, that scientists use to show the sun’s magnetic fields, appear?
Scientists use computer-generated models in which open field lines are represented by purple and green lines and closed field lines, in the form of loops, are yellow
65
True or False: The ebbs and flows of the magnetic field of the sun are cyclical
True
66
What happens to the sun’s magnetic field during a solar minimum?
For several years, the magnetic field of the sun tends to line up with the poles, and sunspots disappear almost completely. This is called a solar minimum
67
What happen several years later after the solar minimum?
Several years later, the magnetic fields grow more disorganized, resulting in hundreds of sunspots and other activity on the surface of the sun. This is called a solar maximum
68
How long does it take the sun to go through one cycle, of its ebbs and flows of magnetic field?
11 years
69
What is the extended quiet period of sunspots or sun activity called?
At times, the solar maxima are higher than others. At times, sunspot activity disappeared entirely for many cycles. This extended quiet period is called the Maunder Minimum
70
True or False: There are sometimes variations in the cycle of the sun
True
71
What event in history is the Maunder Minimum associated with?
The Maunder Minimum is associated with a time on Earth known as the Little Ice Age. During that time, average temperatures were significantly lower on Earth. Scientists speculate that the change in the solar cycle might have caused some of the cooling from that period
72
What drives the sun cycle?
The solar dynamo
73
True or False: Solar flares and CMEs often, but not always, occur at sunspots, and they often occur at the same time
True
74
What is the largest explosion in the solar system?
A solar flare
75
What happens when a solar flare occurs?
When a solar flare occurs, radiation of almost every wavelength of the electromagnetic spectrum, including visible light, is released
76
How long do solar flares last?
Solar flares last from a few seconds to an hour, and can only be seen using specialized telescopes on Earth or in orbit around Earth. They also interfere with satellite transmissions
77
True or False: CMEs expand as they rise
True
78
True or False: Only solar flares and CMEs appear as bright spots
True
79
Solar Wind Definition
Plasma from the sun that spreads outwards through the solar system
80
What affects the shape of the Earth’s magnetosphere?
The shape of Earth’s magnetosphere changes constantly as it interacts with solar wind, which applies pressure on it. As a result, Earth’s magnetosphere is flattened on the daytime side and elongated into a tail on the nighttime side
81
True or False: Conditions inside the magnetosphere are also constantly changing
True
82
What results in solar weather?
The interactions between solar activity and Earth’s magnetosphere result in solar weather, also called space weather, which can affect everyday life on Earth
83
What is the magnetosphere?
The magnetosphere is the space around Earth controlled by Earth’s magnetic field
84
How is the magnetosphere formed?
The magnetosphere is formed when solar wind interacts with Earth’s magnetic field
85
True or False: The magnetosphere acts as a shield, blocking Earth form solar weather, solar wind, and cosmic radiation
True
86
How is the interplanetary magnetic field, or IMF, formed?
Solar wind carries the sun’s magnetic field into space where it is then called the interplanetary magnetic field, or IMF
87
Where does Earth’s magnetic field and the IMF connect?
Earth’s magnetic field and the IMF connect at the polar caps. Energy and particles can enter the magnetosphere here
88
What triggers auroras?
Auroras are triggered by solar wind gusts of CMEs that push energy and particles into Earth’s magnetosphere. The particles interact with gasses in Earth’s atmosphere, creating colorful night skies
89
How do Radiation Belts occur?
Radiation belts occur when charged particles are trapped and held within the inner region of Earth’s magnetosphere. Variations in solar winds can create geomagnetic storms that produce changes in the radiation belts, causing magnetic disturbances on the ground
90
True or False: A better understanding of space weather can help improve the design of satellites
True
91
What are the effects of solar weather determined by?
The sun’s activity
92
How are the emissions of the sun described? (Constant and Dynamic)
Certain emissions from the sun are constant, meaning that they bathe everything in space without any pause. On the other hand, some emissions from the sun are dynamic, meaning that they frequently stop and start and vary in their intensity, often reaching a peak during solar maxima
93
How do geomagnetic storms occur?
Magnetic storms, called geomagnetic storms on Earth, occur when magnetic emissions from CMEs weaken the Earth’s magnetosphere and expose Earth to space weather
94
True or False: Energetic particles are emitted by CMEs and flares and can damage satellites
True
95
What does the sun emit constantly?
The sun constantly emits visible sunlight and solar wind. Solar weather, such as coronal mass ejections and solar energetic particles, arrives more sporadically
96
True or False: Solar Weather can damage Earth’s magnetosphere
True
97
What fraction of the world’s population has cell phones?
2/3
98
What are the affects of CMEs on Earth’s communications?
CMEs can lead to geomagnetic storms that cause natural electric currents beneath Earth’s surface. These naturally made currents can enter power grids, causing overload. Power transformers that convert alternating current from one voltage to another can overheat and sustain damage from this overload
99
What happened in the providence of Quebec in Canada on March 13, 1989?
On March 13, 1989, a solar storm knocked out power in the entire providence of Quebec, Canada for 12 hrs. Scientists witnessed a CME exploding from the sun on March 10, 1989, and three days later it formed a storm that hit North America. It also melted power transformers in New Jersey
100
Electric Current Definition
Movement of positive or negative electric particles
101
What are high frequency (HF) radio waves?
Radio waves at the 1 —30 MHz range are known as high frequency radio waves, often used by commercial airlines, ham radio operators, and various industries
102
What do Solar Flares disturb.
HF Radio Waves
103
How do solar flares affect radio waves?
During a solar flare, the sun sends x-ray photons into Earth’s ionosphere. The ionosphere reflects and modifies HF waves. When the ionosphere has an increased number of photons, there can be a radio blackout on the dayside of Earth. These radio blackouts can cause broadcast television sound, public service radio, cell phones, and navigation systems to fail
104
HF Radio Waves Definition
Radio waves used to transmit radio and other sound signals
105
Ionosphere Definition
The layer of Earth’s atmosphere that has a high concentration of ions and free electrons and is able to reflect radio waves
106
How do solar energetic particles affect communication on Earth?
Solar energetic particles can also disturb radio communications. They cause radiation storms that have a similar effect to solar flares. They can block radio communications, especially at higher latitudes near the poles
107
How many satellites are orbiting Earth?
Over 2,000
108
What do satellites do?
Satellites relay voice, video, and data signals. They provide access to cable television and Internet Services
109
What are satellites susceptible to?
Satellites are susceptible to solar energetic particles, which can cause electrical failure in a satellite
110
How are Radio signals moving to and from satellites affected by solar weather?
Radio signals moving to and from satellites are also susceptible to the same effects of solar weather as HF radio waves
111
What can severe solar weather lead to?
Severe solar weather can lead to a complete loss of communication
112
Satellite Definition
An artificial body placed in orbit around Earth, the moon, or another planet to collect data or communicate
113
What happens as satellites move closer to Earth?
The closer to Earth the satellites are orbiting, the denser the atmosphere, and the more they have to fight drag
114
What happens to satellites when solar weather is active?
When solar weather is active, the atmosphere through which the satellites are moving becomes denser and drag increases
115
Which industries depend on GPS?
More industries are relying on GPS: trucking companies can use it to track shipments of goods while out on the roads and farmers can use GPS to map their fields and guide their tractors, even when it’s is dark outside
116
GPS Definition
A system utilizing satellites that provides users with positioning, navigating, and timing
117
How are GPS signals affected by solar weather?
Since GPS signals travel between Earth and satellites, they are affected by geomagnetic storms. Without solar weather, GPS can find a location within 1 m (3.3 ft). When a storm ramps up, GPS may be able to find a location within 30-40 m (98–131 ft). This can be catastrophic for people who depend on GPS for business
118
What supplies Earth’s energy and determines Earth’s weather?
All of Earth’s weather is ultimately caused by the sun, which supplies most of Earth’s energy
119
What does the uneven heating of the Earth cause?
The uneven heating of Earth’s surface by the sun causes terrestrial winds, cloud formation, precipitation, and other patterns
120
What does solar weather include?
Solar weather includes anything that happens on the sun’s surface, including solar flares, solar prominences, sunspots, and CMEs, and includes events in near-Earth space and Earth’s upper atmosphere
121
How often is solar wind released?
Solar wind is continuously released from the sun’s corona and is a component of solar weather
122
What happened as scientists discovered the amount of energy emitted by the sun varied?
When scientists discovered that the amount of energy emitted by the sun varied, they began to study whether variations in the sun’s appearance affected weather and climate on Earth (which had been of interest for centuries) closer
123
What is the total amount and intensity of energy emitted by the sun called?
The total amount and intensity of the energy emitted by the sun that reaches Earth’s atmosphere is called “Total Solar Irradiance” (TSI)
124
Total Solar Irradiance Definition
A measure of the radiant energy emitted from the sun
125
Solar Minimum Definition
The period of the solar cycle when the sun’s emission s are at their lowest ebb
126
Solar Maximum Definition
The period of the solar cycle when the sun’s emissions are at their highest level
127
How does the type of light the sun emits during its solar minimum and maximum vary?
The sun emits more or less different types of radiation during different periods in its cycle
128
True or False: Some wavelengths have higher variability (in types of radiation)
True
129
Which type of light comprises most of the energy emitted by the sun?
Visible light, with wavelengths of 400 — 800 nm, comprises most of the energy emitted by the sun
130
How is the sun’s output of visible light and energy described as?
The sun’s output of visible light and energy is steady and constant, changing only 0.1% over the solar cycle (when high)
131
How is the sun’s output of infrared light described?
The sun’s output of infrared light, with wavelengths of 800 — 10,000 nm, is also steady, changing by 1% or less over the solar cycle
132
How is the sun’s output of of ultraviolet light described?
The emission of ultraviolet light, with wavelengths of 120 — 400 nm, changes up to 15% over the solar cycle
133
How is the sun’s output of extreme ultraviolet light (EUV) described?
The emission of extreme ultraviolet, with wavelengths 120 nm, can go through changes of 30% to 300% in just minutes
134
What prevents EUV light from having a significant impact on terrestrial climate?
The upper atmosphere absorbs EUV, so these wavelengths don’t have much effect on terrestrial climate
135
What was sent to the International Space Station in 2017?
The Total and Spectral Solar Irradiance Sensor (TSIS-1) measures Total Solar Irradiance with an instrument called the “Total Irradiance Monitor”. With another instrument, the “Spectral Irradiance Monitor”, it measures Solar Spectral Irradiance (SSI), and the amount of ultraviolet, visible, and infrared light emitted from the sun
136
What do NASA scientists want to know about TSI?
NASA scientists want to understand what causes variability in the TSI and how that variability affects Earth’s climate
137
What do the SSI measurements teach scientists about?
SSI measurement teach scientists how the atmosphere responds to the different wavelengths of light (ex: UV light reading will help us better understand to ozone layer)
138
What will happen is scientists can pinpoint trends between TSI and SSI?
If scientists can pinpoint trends between TSI and SSI, they might eventually be able to forecast solar activity and how Earth’s climate will respond to that activity
139
When did NASA begin measuring TSI and SSI?
1978
140
True or False: The amount and intensity of solar energy that reaches Earth influences Earth’s climate
True
141
How does TSI and SSI differ in the solar minimum and the solar maximum?
During solar maximum, the sun emits more UV radiation and the TSI increases by about 0.07%. The effect on Earth’s climate, especially atmospheric warming, are higher during this period
142
What can happen to the atmosphere when solar intensity is weak?
When solar intensity is weak, it can cause periods of atmospheric cooling
143
How is the ozone in Earth’s atmosphere created?
The ozone in Earth’s atmosphere is created by reactions between O2 molecules and UV radiation from the sun
144
What happens to the ozone in Earth’s atmosphere during solar maximum?
During solar maximum, more ozone molecules are formed in Earth’s atmosphere
145
What does the ozone layer of Earth do?
The ozone layer protects Earth’s surface from harmful UVB and UVC radiation
146
What is TSI (Rate)?
TSI is the rate energy reaches Earth’s outer atmosphere
147
How does the cycle of solar activity affect Earth’s temperature?
The cycle of solar activity impacts Earth’s temperature by about 0.18 degrees Fahrenheit
148
What are cosmic rays?
Cosmic rays are small, highly energetic particles that travel through space and strike Earth’s atmosphere
149
True or False: Any change in solar activity changes the flow of cosmic rays
True
150
What do the particles in cosmic rays create?
The particles in cosmic rays create ions, or charged molecules, in the atmosphere, which can modify cloud formation, causing large temperature and weather changes on Earth (More research must be done)
151
What does Earth’s climate depend on? How do greenhouse gasses affect this?
Earth’s climate depends on the balance between incoming solar radiation, outgoing thermal radiation, and Earth’s atmosphere. Small changes in any of these affect climate. Unfortunately, greenhouse gasses block 40% of outgoing thermal radiation. This imbalance causes Earth to heat up
152
How much has Earth’s average temperature increased? How much of this increase is solar heating responsible for?
Earth’s average temperature has increased ANOUT 1.1 degrees Fahrenheit over the last century. Solar heating due to space weather is responsible for about 25% of this change
153
What classification does a G1 geomagnetic storm fall under?
A G1 is a minor geomagnetic storm
154
Do Scientists known if energetic particles that enter Earth’s atmosphere change the composition of the atmosphere?
Scientists don’t know if energetic particles that enter Earth’s atmosphere change the composition of the atmosphere, including its levels of nitrous oxide, and this change the global climate
155
What is the charge of cosmic rays?
Cosmic rays are positively or negatively charged subatomic particles from outside our solar system. They are mainly atomic nuclei — primarily hydrogen and helium — formed by supernova explosions and other high-energy events
156
What happens to Earth’s magnetic field during the solar minimum?
During the solar minimum, Earth’s magnetic field weakens, allowing more of the high-energy cosmic rays to collide with Earth’s atmosphere. This creates ions in the atmosphere
157
What are some natural climate drivers?
The sun, the atmosphere, the land surface, and the ocean
158
True or False: Scientists are studying if cosmic rays are climate drivers
True
159
What are some Human-caused climate drivers.
Emissions of greenhouse gasses and changes in land use
160
What are other possibilities for the Little Ice Age, instead of the solar cycle?
Scientists believe the “Little Ice Age” could have been caused by other contemporary events like volcanic eruptions that blocked sunlight and lower levels of atmospheric CO2, perhaps due to diseases that killed off large portions of the global population (1645 to 1715)
161
What is evidence supporting that solar weather is unlikely to be responsible for the current warming trend of Earth’s atmosphere?
Over the last few decades, the TSI has been lower than normal. Therefore, solar weather is unlikely to be responsible for the current warming trend of Earth’s atmosphere
