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166 Cards in this Set

  • Front
  • Back
What is the namesake of the word astronomy?
Star
What is the nearest and most easily studied star that is visible only during the day from Earth?
The Sun
T or F
Virtually all light, heat, and energy reaching Earth, and life on Earth's surface could not survive without the Sun.
True
What was the process suggested by Kelvin and Helmholtz in the late 1880s about the Sun?
Called the gravitational contraction, these scientist thought that the Sun was a ball of gas and that it is a process where a shrinking gas cloud heats up because some of the gravitational potential energy of gas particles far from the cloud center is converted into thermal energy as the gas moves inward.
Based on gravitational contraction, how old would the Sun be?
25 million years old.
How is it that the Sun generates so much energy for billions of years?
Theory of Relativaty,

2
E=MC and, nuclear fusion
What is the process that the Sun coverts mass into energy?
Nuclear fusion
List the 2 conditions that nuclear fusion requires:
1. extremely high temperatures
2. extremely high densities
How does the Sun keep its core hot and dense?
2 competing forces:
1. gravity pulling inward;
2. pressure pushing outward
What is the gravitational equilibrium?
The natural balance between 2 competing forces of gravity
What is another name for the gravitational equilibrium?
Hydrostatic Equilibrium
Where does the Sun's outward push against gravity come from?
internal gas pressure
What keeps the Sun stable in size?
The Sun's internal pressure precisely balances gravity at every point within it.
What happens to pressure as we look deeper into the Sun?
As we look deeper, pressure increases with depth
What keeps the Sun in balance against the inward pull of gravity?
The fusion, which heats the gas and maintains the pressure
How is it thought now that the Sun was born?
4.5 billion years ago from a collapsing cloud of interstellar gas.
Why does the Sun shine?
4.5 billion years ago GRAVITATIONAL CONTRACTION made the Sun hot enough to sustain nuclear fusion in its core.
What is the Sun made of?
A ball of hot gas
What is the term given to a gas in which atoms are ionized because of the high temperature?
Plasma
T or F
Plasma behaves much like an ordinary gas.
True
Why does plasma create and responds to magnetic fields?
1. many positively charged ions
2. freely moving electrons
What gives the plasma of the Sun the layered structure?
1. differing temperatures
2. differing densities
What mechanism is used to tell us that the Sun is made almost entirely of hydrogen and helium?
Spectroscopy
What is the Sun made almost entirely of?
Hydrogen
Helium
What is the Sun's radius?
nearly 700,000 km (kilometers)
How many times larger is the Sun's radius than the EArth's?
100X (times
T or F
Even sunspots can be larger in size than the Earth.
True
Via what mechanism can we learn what is the mass of the Sun?
Kepler's 3rd Law
What is the mass of the Sun?
30
2 X 10 kilograms
How many times more is the Sun's mass than the Earth's?
300,000X (times)
If you add the mass of all of the planets, how many times more is the Sun's than all of the planets?
1,000X (times)
T or F
The entire Sun rotates at the same rate.
False,
The entire Sun does NOT rotate at the same rate.
How long does it take for the solar equator to rotate?
25 days
How long does it take for the solar poles to rotate?
30 days
How is energy measured?
In joules
What is the term we use to define the rate at which energy is used or released?
Power
What is the standard unit of power?
Watt
Define watt in terms of joules
Watt = 1 joule/second

Watt is equal to 1 joule per second
What is the term used to define the Sun's total power output?
Luminosity
How many watts is the Sun's luminosity?
26
3.8 X 10 watts
To meet current human energy demands for roughly 500,000 years, how much of the Sun's luminosity would be need?
1 second.
What is the term for the stream of charged particles continually blown outward in all directions from the Sun?
Solar wind
Name 2 byproducts of solar wind:
1. the planets' magnetospheres
2. blows back the material that forms the plasma tails of comets
What is the term for the outer layer of the Sun's atmosphere?
Corona
How deep is the Sun's corona?
Several million kilometers above the visible surface of the Sun
What is the temperature of the Sun's corona?
1,000,000 K
What region of the Sun emits most of the Sun's X rays?
The corona
T or F
The Sun's coronoa's density is high.
False.
The Sun's corona's density is low.
T or F
Near the Sun's surface the temperature is even higher than the corona.
False,
Near the Sun's surface the temperature drops to 10,000 K.
What is the term for the middle layer of the Sun's atmosphere?
Chromosphere
What region of the Sun's atmosphere radiates most of the Sun's ultraviolet radiation?
Chromosphere
What is the term for the lowest layer of the Sun's atmosphere?
Photosphere
What is the visible surface of the sun?
Photosphere
T or F
The Sun's photosphere is more dense than the Earth's atmosphere.
False,
The Sun's photosphere is less dense than the Earth's atmosphere.
What is the average temperature of the Sun's photosphere?
6,000 K
How would you describe the motion of the photosphere?
Its surface seethes and churms like a pot of boiling water
In what region of the Sun are sunspots found?
Photosphere
What is the term for the regions of the Sun where there are intense magnetic fields that will cause a compass needle to swing wildly about?
Sunspots
What region of the Sun has high turbulence, spouts of hot gas rising upward, surrounded by cooler gas cascading down from above?
Convection Zone
What is the name of the activity located at the bottom of the photosphere
Convection
Where is energy generated from in the Sun?
The Core
What transports the energy generated by the Sun's core?
Hot gases
What causes the Sun's photosphere to appear seething and churning?
Convection where energy is transported by hot gases rising and cool gases falling.
T or F
The Convection zone is calmer (turbulence wise) than the Radiation zone.
False,
The Radiation zone is calmer than the convection zone.
Which zone is closer to the Sun's core, Radiation or Convection?
Radiation zone
How is energy traveling primarily in the radiation zone?
Energy moves outwardly primarily in the form of photons of light.
What is the temperature of the radiation zone?
10,000,000 K

or 10 million K
What is the source of the Sun's energy?
Nuclear fusion transforming hydrogen into helium
What is the temperature at the center of the Sun's core?
15,000,000 K or

15 million K
How much more is the Sun's core's density than water?
100X (times)
How much more is the pressure in the Sun's core than on the surface of the Earth?
200,000,000,000 X or

200 billion times
T or F
The nuclear reactions that generate energy in the Sun are similar to those used to generate energy in human-built nuclear reactors.
False
The nuclear reactions that generate energy in the Sun are very different from those used to generate energy in human-built nuclear reactors on Earth
How do our nuclear power plants generate energy?
By splitting large nuclei-such as those of uranium or plutonium into smaller ones
What is the term for the splitting of anatomic nucleus?
Nuclear fission
T or F
The Sun makes energy by splitting large nuclei into smaller ones.
False
The Sun makes energy by combining or fusing, 2 or more small nuclei into a larger one.
What is the term for the combining or fusing of 2 or more small nuclei into a larger one?
Nuclear fusion
What region of the Sun has 15 million K plasma that is like a "soup" of hot gas with bare, positively charged atomic nuclei whizzing about at extremely high speeds?
Sun's core
What is the only force in nature that can overcome the electromagnetic repulsion between 2 positively charged nuclei?
The Strong force which binds protons and neutrons together.
T or F
Positively charged nuclei fuse together if they pass close enough for the strong force to overpower electromagnetic repulsion.
True
Why is the Sun's core just right for nuclear fusion?
1. high pressures
2. high temperatures
What causes the nuclei of atoms in the Sun's core to travel at high speeds?
High temperatures
T or F
The higher the temperatures in the Sun's core, the harder the nuclei collide.
True
What prevents the Sun's core from just exploding into space?
The high pressure of the overlying layers over the Sun's core.
T or F
Some stars fuse helium or even heavier elements.
True
How many protons and neutrons are in the most common form of helium?
2 protons
2 neutrons
How many protons are in hydrogen's nuclei?
1 proton
When 4 hydrogen protons collide how many helium nuclei are produced?
1 Helium nucleus with 2 protons and 2 neutrons AND a lot of energy!!!!
What is the term for the sequence of steps that occurs in fusion in the Sun?
Proton-proton chain
What is the first step in the Sun's proton-proton chain?
Collisions between individual protons (hydrogen nuclei)
In the proton-proton chain, what carries the energy?
Gamma rays AND
subatomic particles
Name the subatomic particles that are released in the proton-proton chain of the Sun's nuclear fusion?
neutrinos
positrons
How much less is the mass of 1 helium nucleus than the combined mass of 4 hydrogen nuclei?
0.7% less.
T or F
when 4 hydrogen nuclei fuse into a helium nucleus, a little bit of mass disappears.
True
What formula accounts for the loss of mass in nuclear fusion?
2
E = mc
How much mass is converted into energy every second by the Sun?
4 million tons of matter is turned into energy
How much hydrogen is converted into how much helium every second on the Sun?
600 million tons of hydrogen is converted into
596 million tons of helium
with
4 millions tons converted into energy
T or F
The Sun fuses hydrogen at various rate.
False
The Sun fuses hydrogen at a steady rate.
What acts as the Sun's thermostat keeping the Sun's core temperature and fusion rate steady?
Gravitational equilibrium
How long does it take for solar energy from the sun's core to travel to the photosphere?
Hundreds of thousands of years
Why does it take so long for energy to travel from the core to the photosphere?
Photons are traveling in zigzag patterns.
What causes the photons in the Sun's core to travel in zigzag patterns?
The photon travels only a fraction of a millimeter in any direction before it collides with an electron, deflecting the photons into a new and random direction.
What is a nickname for the the apparent haphazard way that photons travel in the Sun's core before working its way outward?
Random walk
T or F
Where the temperature has dropped, at the top of the radiation zone, the solar plasma absorbs photons more readily.
True
In the convection zone, what color is the cooler gas?
Darker
In the convection zone, what color is the hotter gas?
Bright
How is the energy produced in the solar core and from the photosphere finally released as ?
Thermal radiation
Name the 3 ways we can study the Sun's interior:
1. mathematical models of the Sun
2. observations of "sun quakes"
3. observations of solar neutrinos
What is the primary way we learn about the interior of the Sun?
Creating mathematical model using observed composition and mass as inputs
What are solar vibrations?
Similar to earthquakes on Earth, they result from th movement of gas within the Sun, which generates vibrations that travel through the Sun like sound waves moving through air
How are solar vibrations studied?
Looking at their Doppler shifts
What is helioseismology?
Study of solar vibrations
What causes blueshift, according to Doppler shifts, from a solar vibration?
When light from the portions of the surface of the Sun are rising toward EArth
What causes a slightly redshift, according to Doppler shifts, of a solar vibration?
When the light from portions of the surface of the Sun are falling away from Earth
How thick would a piece of lead need to be to stop an average neutrino from passing through?
1 light year thick
T or F
Neutrinos are prevented from escaping the Sun's core.
False,
Neutrinos produced in the sun's core pass outward through the solar interior almost thought it were empty space.
How fast are neutrinos traveling?
Nearly the speed of light
T or F
Neutrinos never react with matter.
False,
Neutrinos do occasionally interact with matter
Where are neutrino capturers located on Earth?
deep in underground mines
What is the solar neutrino problem?
There was a descripancy between the hypothesized number and the reality of the frequency of neutrinos captured
What was the answer to the solar neutrino problem?
It is thought that some of the neutrinos were hidden because the electron neutrinos may be changing into muon or tau neutrinos.
List the 3 types of neutrinos:
1. electron neutrinos
2. muon neutrinos
3. tau neutrinos
What type of neutrino does the Sun fusion produce?
Electron neutrinos
What neutrino capturer is proving that the solar neutrino problem is solved?
Sudbury Neutrino Observatory in Canada
What is solar weather?
Solar activity such as sunspots, solar flares, etc
What causes solar activity?
magnetic fields
Name the most striking feature of the Sun?
Sunspots
T or F
Sunspots are hotter and therefore brighter than the surrounding photosphere.
False,
Sunspots are cooler and therefore less bright than the surrounding photosphere.
What is the average temperature of the plasma in sunspots?
@ 4,000K
What type of magnetic fields surround sunspots?
Strong magnetic fields
What is the Zeeman effect?
When magnetic fields cause some spectral lines(spectroscopy) to split into 2 or more closely spaced lines.
What are magnetic field lines?
In models and drawing lines drawn that are outlining the locations of the invisible magnetic fields
What does it mean when magnetic field lines are closer together in a drawing?
The magnetic field is stronger in that location
Using magnetic field lines to describe, when do sunspots occur?
Where tightly wound magnetic fields poke nearly straight out from the solar interior.
What is the explanation for sunspots to be cooler than the surrounding gas?
The strong magnetic fields suppress convection with the sunspot and prevent surrounding plasma from entering the sunspot.
How long does the average sunspot last?
A few weeks
T or F
Sunspots usually occur as single events.
False,
Sunspots usually occur in pairs, connected by a loop of a magnetic field that arcs high above the Sun's surface.
What is the term used to describe the gas that is trapped in the loops of magnetic fields that arc high above the Sun's surface?
Solar prominences.
How long to individual solar prominences usually last?
days or weeks
What is the name for the magnetic fields winding through sunspots and prominences that undergo dramatic and sudden changes?
Solar flares
What type of rays do solar flares send out of the Sun?
X rays and fast-moving charged particles.
What is thought to be the reason for solar flares?
When magnetic field loops become so twisted, it thought that they snap and reorganize.
T or F
The plasma nearby a solar flare cools down.
False,
The plasma nearby a solar flare heats up to 100 million K
In what regions of the Sun does solar weather take place?
Chromosphere and the Corona
Why is the Sun hotter at its outer layers than the inner layers?
The Sun's strong magnetic fields carry energy upward from the churning solar surface to the chromosphere and corona.
What are coronal holes?
Some regions of the Corona that barely show up in X ray images.
What is the source of the solar wind?
The particles that escape streaming from the broken magnetic fields that project out into space.
What is the term for the bubbles that particles that escape from solar flares and solar storms travel outward from the Sun?
Coronal Mass Ejections
What happens when a Coronal Mass Ejection hits Earth?
It creates a geomagnetic storm in the Earth's magnetosphere
What inconveniences occur when a Coronal Mass ejection reaches Earth?
1. hamper radio communications
2. disrupt electrical power delivery
3. damage electronic components in orbiting satellites
T or F
Millions of dollars have been lost by companies and the government due to the damages caused by coronal mass ejections that reached the Earth.
True
What type of satellites are vulnerable during periods of strong solar activity?
Satellites in low-Earth orbit.
Why are satellites in lo-Earth orbit more vulnerable to strong solar activity?
An increase solar X rays and energetic particles heat Earth's upper atmosphere, causing it to expand. The density of the gas surrounding the low flying satellites increases that sap their energy and angular momentum, causing drag, and left unchecked the drag causes the satellite to plummet back to Earth
What is the sunspot cycle?
A cycle in which the average number of sunspots on the Sun gradually rises and falls.
What is the term for the time in the sunspot cycle when sunspots are most numerous?
Solar maximum
What is the term for the time in the sunspot cycle when sunspots are the fewest?
Solar minimum.
What is the average length of time between solar maximums?
11 years, but it has been as few as 7 yrs. and as much as 15 yrs.
T or F
There was a time when it was observed that there were virtually no sunspots on the Sun?
True,
1645-1715.
What is the term given to the period of time between 1645 and 1715, when it was observed that were virtually no sunspots on the Sun?
Maunder minimum,
after E.W. Maunder
As a solar cycle begins at the solar minimum, where do sunspots primarily form?
Mid-latitudes (30-40 degrees) on the Sun
Where do sunspots occur primarily as the solar cycle proceeds from the solar minimum?
Lower latitudes, appearing almost at the solar equator
What happens to the Sun's magnetic field at each solar minimum?
The entire magnetic field flip-flops, turning magnetic north into magnetic south and vice versa.
How long is the Sun's complete magnetic cycle?
Avg 22 years since it takes 2 11-yr. sunspot cycles for the magnetic field to return to the way it started.
T or F
Despite changes that occur during the sunspot cycle, the Sun's total output of energy barely changes at all.
True
T or F
Ultraviolet and X rays output from the Sun varies much during the sunspot cycle.
True,
Because ultraviolet and X rays come from the magnetically heated gas of the chromosphere and corona.
T or F
It has been observed that there is a connection between solar activity and and Earth's climate.
True,
During time period, 1645-1715, was a time of exceptionally low temperature in Europe and North America
What is the term given to the time period between 1645 and 1715, when there were exceptionally low temperatures in Europe and North America?
Little Ice Age