PHYS1403_Chapter2
The United States consumes about 2.5*10^19 J of energy in all forms in a year. How many years could you run the United States on the energy of 10^25 J, which can be released by a solar flare?
4*10^5 years
How is meridional flow related to the sun's magnetic dynamo
meridional flow produces additional currents of gas and therefore it produces an additional magnetic dynamo effect
If the color of a sunspot's maximum intensity light is red, is this the color of the sunspot as we see it from Earth? Why or why not?
no, it isn't. The photosphere is too bright to see the true color of sunspots, so they seem as dark spots
Is there any alternative to a high-temperature gas for nuclear fusion to happen?
no, there is not
Some clothing now comes with ultraviolet protection factor (UPF) ratings like sun protection factor (SPF) ratings for sunscreens. A UPF raiting of 50 is considered excellent bc it only allows 1/50 of available UV radiation to pass through it. Construction, dye, chemical treatment, fiber type, efficiency when wet, and condition of garment affect the UPF rating. Can you assume a black shirt has a UPF of 50+? Why or why no?
no; many other factors affewct how much UV radiation passes through the shirt beyond just the dye color
What observations would you make if you were ordered to set up a system that could warn orbiting astronauts of dangerous solar flares?
one way to construct a system to possibly predict and warn astronauts about solar flares would be to send up a satellite into space with devoted cameras and sensors to monitor activity on the solar surface
How does the Babcock model explain the sunspot cycle
pairs of sunspots should occur where the tubes of concentrated magnetic energy burst through the sun's surface during the magnetic cycle
In the radiative zone, energy is carried by which of the following
photons drifting outward
How are granules and supergranules different?
smaller convection cells below the photosphere produce the granules. Convection cells deeper under the photosphere cause the supergranules
Why does the proton-proton chain occur at the center of the sun
that's where the gas is hottest
What atmospheric layers of the sun are associated with this spectrum
the absorption spectrum, which is produced by the photosphere
Explain why the shape extent of the glowing gases are observed to be different for each eclipse
the activity on the surface of the sun changes the shape of the corona
What is the angular diameter of a star the same size as the sun located 5 lightyears from Earth? Is the Hubble Space Telescope able to detect detail ont eh surface of each star? (Use small angle formula: (angular diameter in arc seconds / 2.06*10^50) = linear diameter / distance); the radius of the sun is about 0.7 million k,; the Hubble Space Telescope has a resolution of about 0.1 arc seconds)
the angular diameter is about 0.006 arc seconds. The Hubble Space Telescope is unable to detect details
Which of the following is evidence that granulation is caused by convection below the photosphere
the centers of granules are rising and their edges are falling
What color is the photosphere as viewed from the ground on a clear, cloudless day when the Sun is highest overhead? When the Sun has sunk to just above the ocean's horizon? When the Sun has sunk to half below the ocean's horizon?
the colors are bright yellow, orange-yellow, and red-orange respectively
Energy is carried outward as moving gas in which of the following regions
the convection zone
The sun generates its energy by the proton-proton chain occurring in which of the following regions?
the core
How do solar prominences affect Earth
the energy and gas in a prominence are contained with a magnetic loop and do not affect Earth directly
Explain why the presence of spectral lines of a given element in the solar spectrum tells you that the element is present in the sun, but the absence of the lines would not necessarily mean the element is absent from the sun
the gas may be too hot or too cool, or if the wrong density, for that type of atom to have electrons in the right energy levels to produce significant spectral lines
The radial velocity of a granule's center is found to be - 0.4km/s. If the observed spectral line is Balmer H-alpha at a laboratory wavelength of 656.300 nm, at what wavelength is the line observed? (Use the doppler formula Vt/c=deltawavelength/wavelength)
the line is observed at a wavelength of 656.299 nm
What does the shape of a solar prominence reveal?
the material that produces the prominence is supported by the twisted, arched loops of the sun's magnetic field
When in the cycle does the maximum number of sunspots occur? Is it at the beginning, in the middle, or at the end of the sunspot cycle?
the middle
What energy sources on Earth cannot be thought of as stored sunlight
the nuclear energy stored in the heavy elements with large atomic numbers
Which of the following is the shallowest region?
the photosphere
Astronomers can measure the strength of a magnetic field by observing which of the following?
the separation of the spectral line components
How can astronomers detect structure in the chromosphere?
the structure of the chromosphere is studied primarily using filtergrams
Why does nuclear fusion require high temperatures and high densities?
High temperatures produce particle speeds fast enough to overcome Coulomb force. High density ensures that there are enough particle collisions for reaction
Energy can be transported by convection, conduction, and radiation. Which of these are associated with the interior of the sun?
Inside the sun, energy is transported by both convection and radiation
How does the proton-proton chain produce energy?
It combines light atomic nuclei into heavier atomic nuclei.
To what height and which atmosphere layer does the red color correspond?
It corresponds to a height of 2300 km and higher (the corona)
How are granules and supergranules alike?
granules and supergranules both appear to be the result of convection within the sun
How did neutrino oscillation affect the detection of solar neutrinos by the Davis experiment (which collected approximately one-third as many neutrinos as epxected)
if the oscillations were random, then only about 1/3 of the emitted neutrinos would be the detectable ones
How does consolidation extend scientific understanding?
it helps to know exactly how useful the theory is for explaining behavior outside of its original scope
The radial velocity of a granule's center changes the wavelength of the Balmer H-alpha spectral line from 656.300 nm to 656.299 nm. Is that a blueshift or a redshift? Does that mean the gas is rising, sinking, or moving laterally across the line of sight?
it is blueshift. The gas is rising
What evidence can you give that the corona has a very high temperature?
its spectrum shows that atoms in the corona are highly ionized so the gas must be at a high temperature
the core of the sun represents about how much of the sun's radius
15%
The Zeeman effect occurs when the atoms emitting or absorbing photons are which of the following?
located in a magnetic field
if the sun rotates once every 24.5 days at the equator, once every 27.8 days at latitude 45 degrees, and once every 34.3 days at the poles, what is the average number of days the sun takes to rotate once based on these three numbers/
28.9 days about
Sense of proportion: arrange the following objects in order of increasing size
1) granule 2) sunspot 3) filament
Which of the following best summarizes the proton-proton chain?
6H = He + 2H + E
A 2-megaton nuclear weapon produced 8.0*10^15 J of energy. How much mass vanish when a 2-megaton weapon explodes?
8.9*10^-2 kg
What does the spectrum of a solar prominence reveal?
A solar prominence is an excited, low-density gas with an emission spectrum identical to that of the solar chromosphere
The radius of the sun is 0.7 million km. About what percentage of the radius is taken up by the chromosphere?
About 1 percent
How are astronomers able to explore the layers of the sun below the photosphere?
Astronomers study vibrations of the surface of the Sun caused by movements deep in the Sun and propagated outward like sound waves
What is on the other side of the heliopause as viewed from Earth?
Beyond the heliopause is interstellar space
How can astronomers detect neutrinos from the sun?
By observing the radioactive decay that neutrinos trigger in certain atoms, although these events are rare. In the Davis experiment, neutrinos passing through a 100,000 gallon vat of cleaning fluid triggered chlorine atoms to decay into radioactive argon
Although the sun is gas from its surface to its center, why is it composed of different layers?
Gas behaves differently at different temperatures and pressures
You stayed a little too long outside in the sunshine, and now you have a sunburn. From which atmospheric layer of the sun did the photons originate that resulted in your sunburn? How do you know?
From the photosphere. Although UV wavelengths correspond to blackbody radiation at chromospheric temperatures according to Wien's law, the chromosphere is roughly 1000 times fainter than the photosphere
which energy generation process- chemical burning, fusion, graviational contraction, or fission- do you suppose generated the elements in the sun other than H and He that are listed in teh table below?
Fusion`
if a sunspot has a temperature of 4200K and the average solar photosphere has a temperature of 5780K, how much more energy is emitted in 1 second from a square meter of the photosphere compared to a square meter of the sunspot? (Use Stefan-Boltzmann law)
It emits about 3.6 times more energy
Do you think the atmospheric composition has changed since the sun formed? Why or why not?
It has not changed, because convection currents are only in the outer approx 1/3 of the sun's radius, so they do not reach the core
When astronomers detect the Zeeman Effect, what do they know about the gas that is emitting or absorbing the light?
It is located in a magnetic field
How dos confirmation extend scientific understanding?
It is useful for scientists in order to build confidence in scientific models and to understand when and where the models work
what would the spectrum of an auroral display look like? Why?
It should look like an emission line spectrum. The light by atoms in Earth's upper atmosphere excited from collisions with particles from the solar wind
What kind of activity would the sun have if it didn't rotate differentially?
It would probably not have a strong magnetic field and resulting high-temperature gas above its photosphere
Light helium has which of the following properties?
Mass of 3 and charge of 2
How is meridional flow related to the sunspot cycle?
Meridional flow carries magnetic field bundles toward the poles from active regions at lower latitudes during each sunspot cycle, establishing the foundation of the next cycle's magnetic field
If the color of the photosphere's maximum intensity light is green, is this the color we normally observe for the photosphere? Why or why not?
No it isn't. Our eyes see the whole spectrum instead of only the maximum intensity of color
Does the photosphere really change colors during sunset? Why or why not?
No, it does not. the path length of the sunlight traveling through Earth's atmosphere increases from midday to sunset
What heats the chromosphere and the corona to maintain such high temperatures?
Recent observations indicate that strong magnetic fields are responsible for much of the heating?
Some clothing now comes with UV production UPF ratings like sun protection factor SPF. A UPF rating is 50 is considered excellent because it onyl allows 1/50 of available UV radiation to pass through it. Should all clothing be required to have UPF ratings lsited?
No. It is expensive and some clothing is not worn during exposure to sunlight
Meridional is derived from meridian. Look up the definition of meridian; what is the direction of solar meridional flow?
North or south, changing latitudes as it moves
Why does nuclear fusion in the sun occur only near the center?
Nuclear fusion requires both high temperature and high density. The center of the sun is the hottest and greatest in density
Why does nuclear fusion require that the gas be very hot?
Nuclear fusion requires high temperature so that atomic nuclei will collide with each other at high speed, so they can overcome the electrical repulsion and get close enough to fuse
you live in Phoenix, AZ. A news announcement breaks into your regularly scheduled TV programs to let you know that a large coronal mass ejection is going to collide with Earth tomorrow. What do you do?
One could go to the NOAA website to determine waht, if any, impact on communications might be expected. If necessary, alter the time or means of the telecom that you have planned with colleagues so as to avoid any disruptions
Four protons are combined int he proton-proton chain to make one helium nucleus. But a helium nucleus only contains two protons. What happens to two of the protons at the first step of the chain?
One of them transforms into a neutron and emits a positron and neutrino. Combination of the proton and neutron forms heavy hydrogen, deuterium
How would you know that voyager 1 and voyager 2 has passed through the heliopause?
Passing is expressed by a sharp drop in collisions with low-energy particles, and an increase in galactic cosmic rays
Why can't you see deeper into the sun than the photosphere
Photons emitted from regions deeper than the photosphere are absorbed by overlying layers of gas
Why does the proton-proton chain require a high temperature?
Protons have a positive charge, so they repel each other
How does the Babcock model explain the magnetic cycle of the sun?
Repeated tangling and untangling of the sun's magnetic field
What does it mean when scientists say they are certain? What does scientific certainty really mean?
Scientific certainty is founded on the fact that explanations (theories, laws, etc.) have successfully passed many experimental and observational tests
What evidence can you give that sunspots are magnetic?
Sunspots usually appear in pairs and show a magnetic field that is much stronger than the sun's average magnetic field
What evidence leads astronomers to conclude that temperature increases with height in the chromosphere and the corona?
The atoms in the chromosphere are more highly ionized than atoms in the photosphere. Atoms in the corona are even more highly ionized
The average temperature of the photosphere is 5780 K. What color is the max intensity of a 5780 K blackbody? (There's a graph here)
The color is green
Which atmospheric layers are associated with the sun's continuous spectrum? With its absorption spectrum? With its emission spectrum?
The continuous and absorption spectra - the photosphere The emission spectrum - the chromosphere and the corona
What evidence can you give that granulation is caused by convection?
The granule centers are hotter than the edges and move outward from the sun's center; the edges move oppositely
What is the shape of the heliopause? What determines that shape?
The heliopause is close to a sphere. This is because the solar wind flows in all directions from the Sun.
the smallest detail visible with ground-based solar telescopes is about 1 arc second. How large a region does this represent on the sun? Use angular diameter (in arc seconds)/2.06*10^5 = (linear diameter/distance)
The linear diameter of a region is about 730 km
What information is given in a Maunder butterfly diagram?
The location pattern of sunspots during the sunspot cycle, with sunspots appearing at higher latitudes early in the cycle and closer to the equator later in the cycle
How many watts of radiation does a 1m square region of the sun's photosphere emit, at a temperature of 5780K? (use the stefan-boltzmann law, E=oT^4 J/s/m2; the constant o equals (5.67*10^-8 J/s/m2/K4)
The region emits 6.33*10^7 W
What evidence leads astronomers to conclude that some stars have chromospheres and coronae like those of the sun?
The spectra of many stars contain emission lines in the far ultraviolet and X-ray region. Those lines are formed in low-density, high-temperature gases of a chromosphere and corona.
how much would the wattage of radiation of a blackbody increase if the temperature is increased by a factor of 2? (Use the Stefan-Boltzmann law, E=oT^4 J/s/m2)
The wattage would be 16 times higher
How do you think the sun's appearance would differ if it had no convection inside?
There would be no visible granules or supergranules on the sun. the sunspot cycle would be much different.
Why are sunspots cooler than the photosphere
They contain strong magnetic fields
How can solar flares affect Earth?
They emit large amount of X-rays and ultraviolet radiation that travel to Earth and increase the ionization of Earth's upper atmosphere. Flares also emit large amounts of charged particles that are caught by Earth's magnetic field
Which has a more tightly bound nucleus, uranium or helium? How do you know?
Uranium is more tightly bound than helium is. The binding energy per nuclear particle for helium is lower than that of uranium
The formation of deuterium releases energy in which of the following forms?
a positron and a neutrino
Give an example of a charged subatomic particle and a neutral subatomic particle
a positron is a positively charge subatomic particle and a neutrino is a neutrally charged subatomic particle
How much energy is produced when the sun converts 2 kg of hydrogen into helium? (as a result about 0.66% of the initial mass is converted into energy?)
about 1.2*10^15J
Gusts of the solar wind travel as fast as 1,000km/s. How many days would the solar wind take to reach Earth at this speed? (The average distance to the sun is about 1.5*10^8)
about 1.7 days
a solar flare can release 10^25 J. How many megatons of TNT would be equivalent? (One megaton of TNT produces about 4*10^15 J of energy)
about 2.5*10^9 megatons
Use the luminosity of the sun of 3.84*10^26 J/s (the total amount of energy the sun emits each second) to calculate how much mass the sun converts into energy each second
about 4.27*10^9 kg
how much energy is produced when the sun converts 5 kg of mass into energy?
about 4.5 * 10^17 J
How is meridional flow related to the maunder butterfly diagram?
at the lower layers of the meridional flow, gas moves from the poles toward the equator as the sunspots do
Why does hydrogen, which is abundant in the sun's atmosphere, have relatively weak spectral lines, whereas calcium, which is not abundant, has very strong spectral lines?
at the temperature of the sun's atmosphere, calcium atoms are especially efficient at absorbing photons with wavelengths of visible light, unlike hydrogen
Why does the zeeman effect occur?
atomic energy levels split
You step outside into the sunshine and feel the warmth of the sun. Which of the three wayt to transport energy applies to this scenario?
the warmth of the sun is transported to you by radiation in which the heat energy is transferred by electromagnetic waves
If a sunspot has a temperature of 4200K and the sunspot can be considered a blackbody, what is the wavelength of maximum intensity in nm units and what color is associated with this wavelength? (Refer to Wien's law, lamda max = (2.9*10^6)/T)
the wavelength is 690 nm. The color is red
Have voyager 1 and voyager 2 passed through the heliopause yet?
voyager 1 has passed and voyager 2 hasn't
What information can we obtain from the sun's absorption line spectrum shown below?
we can identify what elements are present in the sun
