Chapter 14 Flashcards
What is Kelvin-Helmholtz contraction?
It’s a process in which an object’s temperature increases due to the compression of its interior gases
What were the two processes proposed to be the source of the Sun’s energy?
- Chemical Reaction
2. Kelvin-Helmholtz contraction
What is the source of the Sun’s energy?
Thermonuclear fusion reactions
How does a thermonuclear fusion reaction occur?
Hydrogen nuclei fuse together to form helium nuclei
What does Einstein’s mass-energy equation govern?
The amount of energy that is produced during the nuclear fusion reactions
What’s Einstein’s mass-energy equation?
E = mc^2
What does “mc” in e=mc^2 stand for?
Missing mass x the speed of light
What type of process will convert mass into energy?
Thermonuclear fusion reaction
Why was Einstein’s mass-energy relation used to explain the energy source of the Sun?
It is the only one that can account for the amount of energy that the Sun produces and the duration the Sun has been this way
What are the conditions that need to be satisfied in order to have thermonuclear reactions?
- High temperature
2. High pressure
What is another name for hydrogen nuclei?
Protons
Why does there need to be a high temperature in order to have thermonuclear reactions?
The higher temperature makes protons move faster, which means that when they run into each other they are going to fuse instead of repeal
What are two other names for thermonuclear hydrogen fusion reactions?
Proton-proton chain and hydrogen burning
What is the difference between nuclear reactions and chemical reactions?
Chemical reactions only affect electrons while nuclear reactions affect the nucleus and change its identity
What is fission?
It’s when you split heavier elements into lighter elements
What is the method that nuclear reactors utilize in order to generate energy?
Fission
What is the disadvantage of fission?
It produces a large amount of radioactive nuclear waste
What is fusion?
It’s when you combine lighter elements to produce heavier elements
What is considered the purest form of energy?
Fusion
True or False:
Fusion produce nuclear waste
False
What is the main product of the thermonuclear fusion inside the Sun?
Helium nucleus
What are the by-products of the thermonuclear fusion inside the Sun?
Neutrinos and gamma radiation
What are neutrinos?
They are subatomic particles that have no charge and very little mass
True or False:
Detecting neutrinos is very difficult
True
Since neutrinos are charge-less, what does that mean when it comes to their interactions?
It means that they don’t interact
Explain hydrostatic equilibrium.
It’s the balancing of inward forces and outward forces
What is the inward and outward force of hydrostatic equilibrium?
The inward force is gravity and the outward force is gas pressure
Why isn’t our sun expanding or contracting?
The sun’s gravity is balancing the inward and outward forces
Explain thermal equilibrium.
The temperature at each layer doesn’t change with time
In thermal equilibrium, if a layer receives more energy than it gives will its temperature increase or decrease??
It will increase
In thermal equilibrium, if a layer gives more energy than it receives will its temperature increase or decrease??
It will decrease
Do the outer layers or the inner layers of the sun have more gravity compression?
The inner layers
What are the mechanisms by which heat can be transported inside the Sun?
Radiation and convection
Explain the radiation mechanism
It is when light travels like a wave and transfers energy
True or False:
Radiation needs a medium
False
Explain the convection mechanism
It is when hot gases or liquids rise and cold gases or liquids fall
What does the convection mechanism set up?
Convection currents
Why doesn’t the conduction mechanism apply to the sun?
It only applies to solids
conduction and solid both have a d
How many distinctive regions does the sun’s interior have? List them
- Core
- Radiative zone
- Convection zone
Where do thermonuclear fusion reactions take place in the sun?
The core
Describe the core
- It’s very hot, it has a high density, and it has a lot of pressure
What carries energy from the core into the radiative zone?
Photons
Why does light have a tough time traveling through the radiative zone?
The solar material in this region is very dense
How long does it take light to travel through the radiative zone?
170,000 years
What is the mechanism by which energy is transported through the convection zone?
Convection
True or False:
In the convection zone hot gas goes up and cooler gas comes down
True
In the convection zone what transports energy to the surface of the sun?
Gas
In the convection zone what does gas transport to the surface of the sun?
Energy/heat
How do we get the experimental evidence for the solar interior?
Helioseismology
What does helioseismology measure?
The vibrations of the sun as a whole
What does the study of helioseismology clearly show?
That there are distinctive regions in the sun
Why is the detection of neutrinos important?
It gives us direct evidence for thermonuclear fusion reactions
What are neutrino telescopes?
It is a big underground tank that is filled with pure distilled water. The tank’s wall is covered with cameras that are used to detect feeble light that is produced in the tank.
Why are neutrino telescopes built underground?
To shield from interferences from other radiations
List the three layers of the Sun’s atmosphere
- Photosphere
- Chromosphere
- Corona
What is the surface of the sun that we see?
Photosphere
As you go up in altitude in the photosphere, what happens to the temperature?
It decreases
Which type of spectrum does photosphere have?
Absorption spectrum
True or False:
Chromosphere has a lower density than photosphere
True
As you go up in the altitude in the chromosphere, what happens to the temperature?
It increases
What color does the light that is emitted by the chromosphere appear to be?
Red
True or False:
You can see the light emitted by the chromosphere on a daily basis
False
When can you see the light that is emitted by the chromosphere?
During a total solar eclipse
What is the outer most region in the sun’s atmosphere?
Corona
As you go up in the altitude in the corona, what happens to the temperature?
It increases
True or False:
You can see the light emitted by the corona on a daily basis
False
Why does the temperature increase with altitude in the corona and the chromosphere?
They both have an intense magnetic field and sound waves
What is granulation?
It is a blotchy pattern that can be seen on the sun’s surface with a telescope
What causes granulation?
Convection of gases in the region under the sun’s surface
What is direct evidence that convection is happening in the convection zone?
Granulation
What are spicules?
They are streams of gases that are pulled upward
What is solar wind?
It’s the gas from the corona that gets ejected into space
How is solar wind produced?
Since the corona has extremely high temperatures it causes some of the materials to have high speeds
What causes the northern and southern lights?
When solar winds are emitted towards earth some of the charged particles will snap our magnetic field. They would then stream towards the earth and interact with our atmosphere. This interaction causes the northern and southern lights.
What are sunspots?
They are irregularly shaped dark regions in the photosphere
Why do sunspots appear dark?
They are cooler than surrounding regions
What causes sunspots?
The sun’s magnetic field
How often does the sun rotate?
Once every 4 weeks
Who was the first to study sunspots?
Galileo
What is differential rotation?
The difference between the equilateral and polar region rotational speeds
What is the sunspot cycle?
It’s the time interval from sunspot maximum to sunspot minimum back to a maximum
What are solar prominences?
They are the loops of glowing gas pushed up around sunspots
What are solar flares?
They are brief eruptions of intense high-energy radiation from the sun’s surface
What do coronal mass ejections do?
They blast a billion tons of hot coronal gas into space
Why do we need to keep a close eye on the violent activities on the Sun?
It can pose health threat to astronomers in the orbit, interfere with satellites, disrupt electronics and communications equipment, cause power outage, and cause wild fires
What causes Kelvin-Helmholtz contraction?
Gravitational contraction
What do thermonuclear fusion reactions convert mass into?
Energy
What is used to explain the energy source of the Sun?
Einstein’s mass-energy relation
How long is a sunspot cycle?
11 years
What does CME stand for?
Coronial Mass Ejections
