Chapter 12 The Sun, Our Star
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The Sun • The Sun is a star, a luminous ball of gas more than 100 times bigger than the Earth • Although seemingly quiescent from a naked eye view, telescopic observations reveal a violent activity – fountains of incandescent gas and twisting magnetic fields • The Sun’s core is equally violent with a furnace of thermonuclear fire converting hydrogen into helium to the tune of an energy production equivalent to the detonation of 100 nuclear bombs • The force of gravity keeps the Sun in check – for now
The Sun • With a radius 100× and a mass of 300,000× that of Earth, the Sun must expend a large amount of energy to withstand its own gravitational desire to collapse • To understand this process requires detailed observations as well as sophisticated calculations involving computer models and the laws of physics
Properties of the Sun • The Sun’s distance from Earth (about 150 million km or 1 AU) was once measured by triangulation, but is now done by radar
• Once the distance is known, its diameter (about 1.4 million km) can be found from its angular size (about 1/2 degree)
Properties of the Sun • From the Sun’s distance and the Earth’s orbital period, Kepler’s modified third law gives the Sun’s mass • Mass and radius, the surface gravity of the Sun is found to be 30× that of Earth • Next, the surface temperature (5780 K) is found from the Sun’s color and the use of Wien’s law for a blackbody
Properties of the Sun • Theoretical considerations then establish the Sun as gaseous throughout with a core temperature of 15 million K
• From the amount of solar energy that reaches the Earth (4 × 1026 watts), this energy must be replenished by fusion processes in its core • The Sun has plenty of hydrogen for fusion: its surface spectra shows hydrogen is 71% and 27% helium
The Structure of the Sun
The Solar Interior • The low density upper layers of the Sun, where any photons created there can freely escape into space is called the photosphere • The photosphere is yellow “surface” we see with our eyes • Layers below the photosphere are opaque, photons created there are readily absorbed by atoms located there
The Solar Interior
• Theoretical calculations show that the Sun’s surface temperature and density both increase as the core is approached – The density is similar to that found at sea level on Earth at the Sun’s surface and 100× that of water at the core
The Radiative Zone • Since the core is hotter than the surface, heat will flow outward from the Sun’s center • Near the Sun’s center, energy is moved outward by photon radiation – a region surrounding the core known as the radiative zone
The Radiative Zone • Photons created in the Sun’s interior do not travel very far before being reabsorbed – energy created in the Sun’s center may take about 16 million years to eventually diffuse to the surface!
The Convection Zone • Above the radiative zone energy is more efficiently transported by the rising and sinking of gas – this is the convection zone
Granulation • Convection manifests itself in the photosphere as granulation, numerous bright regions surrounded by narrow dark zones
The Sun’s Atmosphere
• The extremely low-density gases that lie above the photosphere make up the Sun’s atmosphere
The Sun’s Atmosphere • The density of the atmosphere decreases steadily with altitude and eventually merges with the near-vacuum of space • Immediately above the photosphere, the temperature of the atmosphere decrease but at higher altitudes, the temperature grows hotter, reaching temperatures of several million Kelvin • The reason for the increase in temperature is unknown, but speculation is that Sun’s magnetic field plays an important role
The Chromosphere • The lower part of the atmosphere is referred to as the chromosphere – The chromosphere appears as a thin red zone around the dark disk of a totally eclipsed Sun – The red is caused by the strong red emission line of hydrogen Ha – The chromosphere contains millions of thin columns called spicules, each a jet of hot gas
The Corona
• Temperature in the corona eventually reaches about 1 million K (not much energy though due to low density) • The corona, visible in a total solar eclipse, can be seen to reach altitudes of several solar radii • The corona is not uniform but has streamers and coronal holes dictated by the Sun’s magnetic field
How the Sun Works • Structure of the Sun depends on a balance between its internal forces – specifically, a hydrostatic equilibrium between a force that prevents the Sun from collapsing and a force that holds it together • The inward (holding) force is the Sun’s own gravity, while the outward (non-collapsing) force arises from the Sun’s internal gas pressure • Without balance the Sun would rapidly change!
Pressure in the Sun
• Pressure in a gas comes from atomic collisions • The amount of pressure is in direct proportion to the speed of the atoms and their density and is expressed in the perfect or ideal gas law
Powering the Sun • Given that the Sun loses energy as sunshine, an internal energy source must be present to maintain hydrostatic equilibrium – If the Sun were made of pure coal, the Sun would last only a few thousand years – If the Sun were not in equilibrium, but creating light energy from gravitational energy (the Sun is collapsing), the Sun could last 10 million years – These and many other chemical-based sources of energy are not adequate to account for the Sun’s several billion year age
Powering the Sun • Mass-energy is the key – In 1905, Einstein showed that energy and mass were equivalent through his famous E = mc2 equation – 1 gram of mass is equivalent to the energy of a small nuclear weapon – The trick is finding a process to convert mass into other forms of energy
Powering the Sun • A detailed process for mass conversion in the Sun called nuclear fusion was found: – Sun’s core temperature is high enough to force positively charged protons close enough together to bind them together via the nuclear or strong force – The net effect is that four protons are converted into a helium nucleus (plus other particles and energy) in a threestep process called the proton-proton chain
Isotopes • In the protonproton cycle, isotopes are intermediate steps between protons and their ultimate fusion into 4He.
The Proton-Proton Chain
The Proton-Proton Chain: Step 1
The Proton-Proton Chain: Step 2
The Proton-Proton Chain: Step 3
Solar Neutrinos • The nuclear fusion process in the Sun’s core creates neutrinos • Neutrinos lack electric charge, have a very small mass, escape the Sun’s interior relatively unaffected, and shower the Earth (about 1 trillion pass through a human per second)
Solar Neutrinos • A neutrino’s low reactivity with other forms of matter requires special detection arrangements – Detectors buried deep in the ground to prevent spurious signals as those produced by cosmic rays (high energy particles, like protons and electrons, with their source beyond the Solar System) – Large tanks of water and special light detectors
Solar Neutrinos • Detected neutrinos are about three times less than predicted – possible reasons: – Model of solar interior could be wrong – Neutrinos have properties that are not well understood
• Current view to explain measured solar neutrinos: neutrinos come in three varieties (instead of previous one), each with a different mass, and Earth detectors cannot detect all varieties • Important ramifications: A solar astronomy observation of neutrinos may lead to a major revision of our understanding of the basic structure of matter
Solar Seismology • Solar seismology is the study of the Sun’s interior by analyzing wave motions on the Sun’s surface and atmosphere • The wave motion can be detected by the Doppler shift of the moving material • The detected wave motion gives temperature and density profiles deep in the Sun’s interior • These profiles agree very well with current models
Solar Seismology
Solar Magnetic Activity • Surface waves are but one type of disturbance in the Sun’s outer layers • A wide class of dramatic and lovely phenomena occur on the Sun and are caused by its magnetic field
Interaction of Fields and Particles • Charged particles tend to spiral along magnetic field lines easier than they drift across them • Bulk motion of plasma carries the field along with it. • Motion of the field carries particles along with it
Sunspots • Dark-appearing regions ranging in size from a few hundred to a few thousand kilometers across • Last a few days to over a month • Darker because they are cooler than their surroundings (4500 K vs 6000 K) • Cooler due to stronger magnetic fields within them
Origin of Sunspots
• Starved of heat from below, the surface cools where the magnetic fields breach the surface creating a dark sunspot
Prominences • Prominences are huge glowing gas plumes that jut from the lower chromosphere into the corona
Solar Flares • Sunspots give birth to solar flares, brief but bright eruptions of hot gas in the chromosphere • Hot gas brightens over minutes or hours, but not enough to affect the Sun’s total light output
Solar Flares • Strong increase in radio and x-ray emissions • Intense twisting and “breakage” of magnetic field lines is thought to be the source of flares
Coronal Mass Ejections • Coronal mass ejections can explosively shoot gas across the Solar System and result in spectacular auroral displays
Impact of Solar Flares
Heating of the Chromosphere and Corona • While the Sun’s magnetic field cools sunspots and prominences, it heats the chromosphere and corona • Heating is caused by magnetic waves generated in the relatively dense photosphere – These waves move up into the thinning atmospheric gases, grow in magnitude, and “whip” the charged particles found there to higher speeds and hence higher temperatures – Origin of waves may be from rising bubbles in convection zone
Heating of the Chromosphere and Corona
The Solar Wind • The corona’s high temperature gives its atoms enough energy to exceed the escape velocity of the Sun • As these atoms stream into space, they form the solar wind, a tenuous gas of hydrogen and helium that sweeps across the entire Solar System • The amount of material lost from the Sun via the Solar Wind is insignificant • Typical values at the Earth’s orbit: a few atoms per cm3 and a speed of about 500 km/sec • At some point, the solar wind mingles with interstellar space
The Solar Cycle
• Sunspot, flare, and prominence activity change yearly in a pattern called the solar cycle • Over the last 140 years or so, sunspots peak in number about every 11 years • Climate patterns on Earth may also follow the solar cycle
Differential Rotation
• The Sun undergoes differential rotation, 25 days at the equator and 30 at the poles
Cause of the Solar Cycle
• This rotation causes the Sun’s magnetic field to “wind up” increasing solar activity (magnetic field “kinks” that break through the surface) as it goes
• The cycle ends when the field twists too “tightly” and collapses – the process then repeats
Changes in the Solar Cycle
• The cycle may vary from 6 to 16 years • Considering the polarity direction of the sunspots, the cycle is 22 years, because the Sun’s field reverses at the end of each 11-year cycle • Leading spots in one hemisphere have the same polarity, while in the other hemisphere, the opposite polarity leads
Solar Cycle and Climate
• Midwestern United States and Canada experience a 22-year drought cycle • Few sunspots existed from 1645-1715, the Maunder Minimum, the same time of the “little ice age in Europe and North America • Number of sunspots correlates with change in ocean temperatures
Astronomy Chapter 12 Review
Approximately how massive is the Sun as compared to the Earth? A. 100 times B. 300 times C. 3000 times D. 300,000 times E. One million times
Approximately how massive is the Sun as compared to the Earth? A. 100 times B. 300 times C. 3000 times D. 300,000 times E. One million times
If you could manage to stand on the Sun, you would weigh approximately ____ times more than your weight on the Earth. A. 10 B. 30 C. 100 D. 300,000
If you could manage to stand on the Sun, you would weigh approximately ____ times more than your weight on the Earth. A. 10 B. 30 C. 100 D. 300,000
The sunlight we receive on the Earth originates from the Sun's A. Radiative zone. B. Photosphere. C. Chromosphere. D. Corona.
The sunlight we receive on the Earth originates from the Sun's A. Radiative zone. B. Photosphere. C. Chromosphere. D. Corona.
The hottest part of the Sun is A. The core. B. The radiative zone. C. The photosphere. D. The Corona.
The hottest part of the Sun is A. The core. B. The radiative zone. C. The photosphere. D. The Corona.
The Sun's core is generating energy in the form of ________. A. Gamma rays B. Ultraviolet C. X-rays D. Visible E. Radio
The Sun's core is generating energy in the form of ________. A. Gamma rays B. Ultraviolet C. X-rays D. Visible E. Radio
Sunspots are dark because they are
A. Land masses like continents on the Earth. B. Holes in the photosphere, allowing astronomers to view into the Sun's interior. C. Shadows from clouds in the Sun's atmosphere. D. Slightly cooler regions meaning they emit less light than the surrounding areas.
Sunspots are dark because they are
A. Land masses like continents on the Earth. B. Holes in the photosphere, allowing astronomers to view into the Sun's interior. C. Shadows from clouds in the Sun's atmosphere. D. Slightly cooler regions meaning they emit less light than the surrounding areas.
At which observatory listed below are scientists trying to capture neutrinos? A. SOHO (Solar & Heliospheric Observatory). B. Super Kamiokande, Japan. C. GONG (Global Oscillations network group). D. Hubble Space Telescope.
At which observatory listed below are scientists trying to capture neutrinos? A. SOHO (Solar & Heliospheric Observatory). B. Super Kamiokande, Japan. C. GONG (Global Oscillations network group). D. Hubble Space Telescope.
Which part of the Sun is covered with granules? A. Corona B. Chromosphere C. Photosphere D. Core
Which part of the Sun is covered with granules? A. Corona B. Chromosphere C. Photosphere D. Core
Which part of the Sun is not in hydrostatic equilibrium? A. Core B. Radiation zone C. Convection zone D. Corona
Which part of the Sun is not in hydrostatic equilibrium? A. Core B. Radiation zone C. Convection zone D. Corona
The solar wind is created in the Sun's _______. A. Core B. Radiation zone C. Convection zone D. Corona
The solar wind is created in the Sun's _______. A. Core B. Radiation zone C. Convection zone D. Corona
What is the name of a sudden, highly energetic, eruptive explosion on the surface of the Sun?
A. Sunspot B. Granulation C. Flare D. Coronal hole
What is the name of a sudden, highly energetic, eruptive explosion on the surface of the Sun?
A. Sunspot B. Granulation C. Flare D. Coronal hole
The diameter of the Sun is determined by measuring its ____ and _____. A. Volume; density B. Distance; volume C. Distance; angular size
The diameter of the Sun is determined by measuring its ____ and _____. A. Volume; density B. Distance; volume C. Distance; angular size
The surface temperature of the Sun can be measured using ____. A. Kepler's third law B. The Doppler shift C. Wien's law
The surface temperature of the Sun can be measured using ____. A. Kepler's third law B. The Doppler shift C. Wien's law
The temperature at the Sun's core is about _____. A. 15,000,000 K B. 1,500,000 K C. 150,000 K D. 15,000 K
The temperature at the Sun's core is about _____. A. 15,000,000 K B. 1,500,000 K C. 150,000 K D. 15,000 K
The Sun's composition by the % of mass is 71% ____, 27% _____ and 2% _____. A. Hydrogen; oxygen; helium B. Helium; hydrogen; other elements C. Hydrogen; helium; other elements
The Sun's composition by the % of mass is 71% ____, 27% _____ and 2% _____. A. Hydrogen; oxygen; helium B. Helium; hydrogen; other elements C. Hydrogen; helium; other elements
The energy in the Sun's core is produced by A. Chemical reaction of hydrogen and helium. B. Fusion of hydrogen to helium. C. Radioactive decay. D. Release of gravitational potential energy.
The energy in the Sun's core is produced by A. Chemical reaction of hydrogen and helium. B. Fusion of hydrogen to helium. C. Radioactive decay. D. Release of gravitational potential energy.
Light travels for about _____ to reach the Sun's surface from the Sun's core, and about ____ to reach the Earth from the Sun's surface. A. 16 million years; 8 minutes B. 100 years; 8 minutes C. 1 minute; 8 seconds D. 100 years; 8 seconds
Light travels for about _____ to reach the Sun's surface from the Sun's core, and about ____ to reach the Earth from the Sun's surface. A. 16 million years; 8 minutes B. 100 years; 8 minutes C. 1 minute; 8 seconds D. 100 years; 8 seconds
The Sun's atmosphere consists of the _____ and the _____. A. Photosphere; chromosphere B. Photosphere; corona C. Chromosphere; corona
The Sun's atmosphere consists of the _____ and the _____. A. Photosphere; chromosphere B. Photosphere; corona C. Chromosphere; corona
The temperature at the ____ of the Sun's chromosphere is higher than the temperature ____.
A. Base; at the top of the chromosphere B. Top; at the base of the chromosphere C. Top; of the Sun's corona D. Base; of the Sun's corona
The temperature at the ____ of the Sun's chromosphere is higher than the temperature ____.
A. Base; at the top of the chromosphere B. Top; at the base of the chromosphere C. Top; of the Sun's corona D. Base; of the Sun's corona
How is the composition of the Sun today different than when it formed 4.6 billion years ago? A. There is no difference, the composition has not changed. B. There is now more hydrogen and less helium. C. There is now more helium and less hydrogen. D. The amount of hydrogen and helium has not changed but the amount of heavier elements has decreased.
How is the composition of the Sun today different than when it formed 4.6 billion years ago? A. There is no difference, the composition has not changed. B. There is now more hydrogen and less helium. C. There is now more helium and less hydrogen. D. The amount of hydrogen and helium has not changed but the amount of heavier elements has decreased.
____ provides a way to measure the speed of seismic waves in the Sun. A. Newton's 3rd law B. Wien's law C. The Doppler effect D. Kepler's 3rd law
____ provides a way to measure the speed of seismic waves in the Sun. A. Newton's 3rd law B. Wien's law C. The Doppler effect D. Kepler's 3rd law
The Sun rotates _____ at its equator than at its poles. A. Slower B. The same C. Faster
The Sun rotates _____ at its equator than at its poles. A. Slower B. The same C. Faster
The _____ a period _______, that coincides with _______. A. Sunspot cycle is; of 11 years; the Sun's rotation around its axis B. Maunder Minimum is; of low sunspot activity; the "little ice age" in the late 17th century C. Magnetic cycle is; of 22 years; a period of intense solar and earthquakes D. Solar cycle is; of high sunspot activity; the cycle of the planetary alignments
The _____ a period _______, that coincides with _______. A. Sunspot cycle is; of 11 years; the Sun's rotation around its axis B. Maunder Minimum is; of low sunspot activity; the "little ice age" in the late 17th century C. Magnetic cycle is; of 22 years; a period of intense solar and earthquakes D. Solar cycle is; of high sunspot activity; the cycle of the planetary alignments
A solar prominence is essentially
A. A cloud of hot gas lifting off the surface of the Sun. B. An eruption of gas heated by the sudden recombination of opposite polarity parts of the Sun's magnetic field. C. A plasma confined to a magnetic tube sticking out of the surface of the Sun. D. An aurora occurring in the Sun's atmosphere instead of the Earth's.
A solar prominence is essentially
A. A cloud of hot gas lifting off the surface of the Sun. B. An eruption of gas heated by the sudden recombination of opposite polarity parts of the Sun's magnetic field. C. A plasma confined to a magnetic tube sticking out of the surface of the Sun. D. An aurora occurring in the Sun's atmosphere instead of the Earth's.
One way to probe the rate of nuclear reactions in the center of the Sun is by studying the _________ produced because _________. A. Positrons; they annihilate into gamma rays of very specific energies. B. Neutrinos; they pass out of the Sun without undergoing a random walk. C. Heavy hydrogen; it has different spectral lines than normal hydrogen. D. Wave motions; they can be measured at the Sun's surface.
One way to probe the rate of nuclear reactions in the center of the Sun is by studying the _________ produced because _________. A. Positrons; they annihilate into gamma rays of very specific energies. B. Neutrinos; they pass out of the Sun without undergoing a random walk. C. Heavy hydrogen; it has different spectral lines than normal hydrogen. D. Wave motions; they can be measured at the Sun's surface.
Since nuclear fusion in the Sun creates energy from matter, why doesn't it violate the law of conservation of energy? A. Conservation of energy only applies to mechanical and electrical systems, not to nuclear physics. B. The energy actually comes from the motion of the four separate hydrogen atoms, which move less bound together as one helium atom. C. Matter and energy are equivalent, as expressed by Einstein's equation E = mc2. D. It does, but conservation of energy is only a law in Newtonian physics, which does not work under the conditions at the center of the Sun.
Since nuclear fusion in the Sun creates energy from matter, why doesn't it violate the law of conservation of energy? A. Conservation of energy only applies to mechanical and electrical systems, not to nuclear physics. B. The energy actually comes from the motion of the four separate hydrogen atoms, which move less bound together as one helium atom. C. Matter and energy are equivalent, as expressed by Einstein's equation E = mc2. D. It does, but conservation of energy is only a law in Newtonian physics, which does not work under the conditions at the center of the Sun.
If the Sun's rotation carries two sunspots around the side out of sight, you might see them again in about
A. Twelve hours. B. Two weeks. C. A month. D. Six months.
If the Sun's rotation carries two sunspots around the side out of sight, you might see them again in about
A. Twelve hours. B. Two weeks. C. A month. D. Six months.
Generally speaking, activity on the surface of the Sun is primarily driven by A. Gravity. B. Thermodynamics. C. Electromagnetism. D. Nuclear reactions.
Generally speaking, activity on the surface of the Sun is primarily driven by A. Gravity. B. Thermodynamics. C. Electromagnetism. D. Nuclear reactions.
The photosphere A. Is the part of the Sun where nuclear fusion is occurring. B. Is the layer of the Sun where it transitions from being opaque to transparent. C. Is the hottest part of the Sun. D. Is the densest part of the Sun.
The photosphere A. Is the part of the Sun where nuclear fusion is occurring. B. Is the layer of the Sun where it transitions from being opaque to transparent. C. Is the hottest part of the Sun. D. Is the densest part of the Sun.
From the center out, the correct order of the parts of the Sun is
A. Core, convection zone, radiative zone, photosphere, chromosphere, corona. B. Radiative zone, core, chromosphere, convection zone, photosphere, corona. C. Core, convection zone, photosphere, chromosphere, corona, radiative zone. D. Core, radiative zone, convection zone, photosphere, chromosphere, corona
From the center out, the correct order of the parts of the Sun is
A. Core, convection zone, radiative zone, photosphere, chromosphere, corona. B. Radiative zone, core, chromosphere, convection zone, photosphere, corona. C. Core, convection zone, photosphere, chromosphere, corona, radiative zone. D. Core, radiative zone, convection zone, photosphere, chromosphere, corona
The Zeeman effect, in which energy levels of electrons are shifted and produce a corresponding split in spectral lines observed, is used to measure _________ at the Sun's surface. A. Magnetic field strength B. The intensity of gamma rays C. Gravitational field strength D. The velocity and oscillations of gas
The Zeeman effect, in which energy levels of electrons are shifted and produce a corresponding split in spectral lines observed, is used to measure _________ at the Sun's surface. A. Magnetic field strength B. The intensity of gamma rays C. Gravitational field strength D. The velocity and oscillations of gas
The solar cycle is a result of the A. Nuclear fusion at the core of the Sun. B. Loss of energy in the Sun's magnetic field through flares, sunspots, and prominences. C. Differential rotation of the Sun. D. Motion in the convection zone cycling material into the Sun's core.
The solar cycle is a result of the A. Nuclear fusion at the core of the Sun. B. Loss of energy in the Sun's magnetic field through flares, sunspots, and prominences. C. Differential rotation of the Sun. D. Motion in the convection zone cycling material into the Sun's core.
In the Sun, nuclear fusion occurs A. In the core and the radiative zone. B. Only in the core. C. Throughout the entire star.
In the Sun, nuclear fusion occurs A. In the core and the radiative zone. B. Only in the core. C. Throughout the entire star.
Although the Sun's core has a density much greater than rock it is considered a gaseous object because A. The Sun's high internal temperatures prevent the atoms from bonding together to form a liquid or a solid. B. A large fraction of the Sun's interior is made of electromagnetic radiation (light). C. It is composed mostly of hydrogen. D. The Sun formed from the solar nebula which itself was a large gas and dust cloud.
Although the Sun's core has a density much greater than rock it is considered a gaseous object because A. The Sun's high internal temperatures prevent the atoms from bonding together to form a liquid or a solid. B. A large fraction of the Sun's interior is made of electromagnetic radiation (light). C. It is composed mostly of hydrogen. D. The Sun formed from the solar nebula which itself was a large gas and dust cloud.
Astronomers know what the solar interior is like by A. observing the interior directly. By using the appropriate filters it is possible to reduce the bright glow of the Sun and to peer directly at the Sun's interior. B. constructing a miniature Sun in the laboratory and extrapolating the results to the real Sun. C. using locally tested physics combined with observations to build a mathematical model of what the Sun should be like in its interior.
D. sending probes directly into the Sun and sending back the information.
Astronomers know what the solar interior is like by A. observing the interior directly. By using the appropriate filters it is possible to reduce the bright glow of the Sun and to peer directly at the Sun's interior. B. constructing a miniature Sun in the laboratory and extrapolating the results to the real Sun. C. using locally tested physics combined with observations to build a mathematical model of what the Sun should be like in its interior.
D. sending probes directly into the Sun and sending back the information.
What holds the Sun together? A) Electrostatic forces between ions in its interior. B) Gas pressure. C) Its gravitational force. D) Nothing: the Sun is actually expanding very slowly.
What holds the Sun together? A) Electrostatic forces between ions in its interior. B) Gas pressure. C) Its gravitational force. D) Nothing: the Sun is actually expanding very slowly.
The Sun produces its energy through A) the fusion of neutrinos into helium. B) the fusion of positrons into hydrogen. C) the fusion of hydrogen into helium. D) electric currents generated in its core.
The Sun produces its energy through A) the fusion of neutrinos into helium. B) the fusion of positrons into hydrogen. C) the fusion of hydrogen into helium. D) electric currents generated in its core.
The sun's energy comes from A) the release of magnetic energy. B) the conversion of mass into energy. C) its rotation slowing down. D) meteors and asteroids striking its surface.
The sun's energy comes from A) the release of magnetic energy. B) the conversion of mass into energy. C) its rotation slowing down. D) meteors and asteroids striking its surface.
What is the Sun's outermost atmosphere called? A) The corona C) The photosphere
B) The chromosphere D) The radiative zone
What is the Sun's outermost atmosphere called? A) The corona C) The photosphere
B) The chromosphere D) The radiative zone
How do a prominence and a flare differ? A) A prominence is a huge plume of glowing gas trapped in the Sun's magnetic field; a flare is a brief, bright eruption in the chromosphere. B) A prominence is brief, bright eruption in the chromosphere; a flare is a tenuous flow of hydrogen and helium that sweeps across the Solar System. C) A prominence is a jet of hot gas thousands of kilometers long; a flare is an immense bubble of hot gas rising from deep within the Sun. D) There is no difference.
How do a prominence and a flare differ? A) A prominence is a huge plume of glowing gas trapped in the Sun's magnetic field; a flare is a brief, bright eruption in the chromosphere. B) A prominence is brief, bright eruption in the chromosphere; a flare is a tenuous flow of hydrogen and helium that sweeps across the Solar System. C) A prominence is a jet of hot gas thousands of kilometers long; a flare is an immense bubble of hot gas rising from deep within the Sun. D) There is no difference.
What is solar seismology? A) The study of the Sun's atmosphere by analyzing waves in the Sun's interior. B) The study of the Sun's interior by analyzing waves in the Sun's atmosphere. C) The study of gravitational waves from the Sun. D) The study of the Sun's changing size.
What is solar seismology? A) The study of the Sun's atmosphere by analyzing waves in the Sun's interior. B) The study of the Sun's interior by analyzing waves in the Sun's atmosphere. C) The study of gravitational waves from the Sun. D) The study of the Sun's changing size.
About how long is the solar cycle (evidenced by sunspots)? A)
3 years
B)
5 days
C)
11 years
D)
33 years
About how long is the solar cycle (evidenced by sunspots)? A)
3 years
B)
5 days
C)
11 years
D)
33 years
The Sun is supported against the crushing force of its own gravity by (a) magnetic forces. (b) its rapid rotation. (c) the force exerted by escaping neutrinos. (d) gas pressure. (e) the antigravity of its positrons.
The Sun is supported against the crushing force of its own gravity by (a) magnetic forces. (b) its rapid rotation. (c) the force exerted by escaping neutrinos. (d) gas pressure. (e) the antigravity of its positrons.
According to the ideal gas law, if the temperature of a gas is made 4 times higher, which of the following is a possible result? (More than one answer may be correct.) (a) Its pressure increases by 4 times and its density remains the same. (b) Its density increases by 4 times and its pressure remains the same. (c) Its pressure and density both double. (d) Its pressure increases by 4 times while its density decreases by 4 times. (e) Its pressure and density both decrease by 2 times.
According to the ideal gas law, if the temperature of a gas is made 4 times higher, which of the following is a possible result? (More than one answer may be correct.) (a) Its pressure increases by 4 times and its density remains the same. (b) Its density increases by 4 times and its pressure remains the same. (c) Its pressure and density both double. (d) Its pressure increases by 4 times while its density decreases by 4 times. (e) Its pressure and density both decrease by 2 times.
The primary method astronomers use to measure oscillations on the surface of the Sun is by (a) comparing telescopic images. (b) magnetograms from measuring Zeeman splitting of spectral lines. (c) measuring the Doppler shift of absorption lines from the surface. (d) Xray and ultraviolet imaging by satellites. (e) sonic detection.
The primary method astronomers use to measure oscillations on the surface of the Sun is by (a) comparing telescopic images. (b) magnetograms from measuring Zeeman splitting of spectral lines. (c) measuring the Doppler shift of absorption lines from the surface. (d) Xray and ultraviolet imaging by satellites. (e) sonic detection.
Differential rotation results in (a) the solar wind. (b) a wound up magnetic field. (c) the Maunder minimum. (d) the Sun's generation of energy. (e) All of the above.
Differential rotation results in (a) the solar wind. (b) a wound up magnetic field. (c) the Maunder minimum. (d) the Sun's generation of energy. (e) All of the above.
