Q&A Hero

Q: In the proton-proton cycle, the positron is A) massless. B) a spin conservation particle. C) an anti-electron. D) the chief means energy reaches the photosphere. E) intermediate between the proton and neutron in mass.

Q: The primary source of the Sun's energy is A) oxidation of carbon in the core. B) gravitational collapse of the helium towards the core. C) dark energy. D) the strong force fusing hydrogen into helium. E) the weak force creating energy from uranium decay.

Q: The solution to the solar neutrino problem was A) the Sun's core is cooling down, producing less neutrinos that expected. B) the corona is opaque to much of the neutrino radiation. C) the Earth's ozone layer absorbs 2/3 of the neutrinos in transit. D) 2/3 of the neutrinos transform into a new type during the 8 minute trip to Earth. E) our solar energy equations were just wrong, and needed much reworking.

Q: In the proton-proton cycle, the helium atom and neutrino have less mass than the original hydrogen. What happens to the "lost" mass? A) It is recycled back into hydrogen. B) It is ejected into space. C) It is converted to energy. D) It is transformed into electrons. E) Conservation of mass dictates no mass can be lost.

Q: The critical temperature to initiate the proton-proton cycle in the cores of stars is A) 3,000 K. B) 5,800 K. C) 2,300,000 K. D) 10 million K. E) 100 million K.

Q: What natural barrier usually prevents two protons from combining? A) dark energy B) gravity C) electromagnetic repulsion D) the strong nuclear force E) the weak nuclear force

Q: While observing the Sun, you note a large number of sunspots. What can you conclude? A) The Sun is less luminous than usual. B) This is a period of low solar activity. C) Earth's climate will be unusually cold. D) The Sun's rotation is slower than average. E) There are likely to be an above average number of flares and prominences.

Q: Suppose a large flare is detected optically. How long until radio interference arrives? A) simultaneously B) 8.5 minutes later C) about 12 hours D) about four days E) no relation between the two

Q: Sunspots are dark splotches on the Sun. Which statement is true? A) They are hotter than the surrounding areas of the Sun. B) They are extremely cold objects, as cold as Pluto. C) They are extremely hot, but cooler than the surrounding areas of the Sun. D) They are solid bodies floating on the surface of the Sun. E) They are associated with areas of very low magnetic fields.

Q: During a period of high solar activity, the corona A) disappears. B) is more irregular. C) cools almost to the temperature of the photosphere. D) becomes smooth and even. E) shrinks to half its normal size.

Q: Sunspots A) are always found close to the Sun's poles. B) come in pairs, representing the north and south magnetic fields. C) were most numerous during the Maunder Minimum. D) travel over the surface of the Sun from pole to pole. E) are relatively constant in number every year.

Q: A maximum in solar activity should next occur about A) 2015. B) 2017. C) 2019. D) 2023. E) 2027.

Q: The most striking example of solar variability was the A) Dust Bowl drought of the 1930s. B) Maunder Minimum from 1645-1715. C) Sporer Minimum that doomed the Anasazi. D) the fall of Rome. E) Joseph's seven lean years in the Old Testament.

Q: As the Sun rotates, an individual sunspot can be tracked across its face. From eastern to western limb, this takes about A) 12 hours. B) a week. C) two weeks. D) a month. E) 5.5 years.

Q: Visible sunspots lie in the A) chromosphere. B) transition zone. C) corona. D) radiative zone. E) granulation in the photosphere.

Q: How long does the sunspot cycle last, on average? A) between 25 and 35 days B) 365.25 days C) about seven years D) about 11 years E) about 76 years

Q: A loop of gas following the magnetic field lines between sunspots' poles is A) a flare. B) a ray. C) a coronal hole. D) a prominence. E) a coronal mass ejection.

Q: From inside out, which is in the correct order for the structure of the Sun? A) core, convective zone, radiative zone B) core, photosphere, radiative zone, corona C) core, radiative zone, convective zone, chromosphere D) core, chromosphere, photosphere E) core, convective zone, radiative zone, granulation

Q: The solar winds blow outward from A) sunspots. B) flares. C) the entire photosphere. D) coronal holes. E) the Sun's poles only.

Q: When we glimpse the chromosphere at the start and end of totality, its color is A) green (the famous flash). B) yellow, like the photosphere below it. C) red, due to ionized hydrogen at lower pressure. D) blue, due to the ionization of nitrogen by the magnetic fields. E) white from the moonlight.

Q: The outward pressure of hot gas in the Sun A) is balanced by the inward gravitational pressure. B) is increasing the Sun's diameter. C) is cooling the photosphere. D) is responsible for variations in the sunspot cycle. E) weakens the magnetic field.

Q: What two energy transport mechanisms, in order from outside the core to the surface, are found in the Sun? A) convection, conduction B) radiation, convection C) conduction, radiation D) radiation, conduction E) conduction, convection

Q: Typically a granule in the photosphere is about A) the size of a city, 20-30 kilometers across. B) the size of Texas, about 1,000 km across. C) the size of our Moon, about 3,000 km across. D) the size of Earth, around 12,000 km across. E) as big as Jupiter, around 100,000 km wide.

Q: Which of these are not associated with the active Sun? A) sunspots B) prominences C) granulation D) flares E) aurora

Q: The average density of the Sun is most similar to which object? A) Halley's Comet's nucleus B) the Earth C) Mercury D) the Moon E) Jupiter

Q: What is the meaning of the solar constant? A) the regularity of the 11 year sunspot cycle B) the fact that features on the Sun appear to never change C) the stability of the Sun's luminosity for as long as life has existed on Earth D) the amount of energy the Earth receives per unit area and unit time E) the fact that the amount of hydrogen turning into helium in the core is fixed

Q: Given that a large sunspot, about 100 smaller than the Sun, is about the same size as our planet, how many Earths could fit inside the Sun's vast volume? A) 100 B) 1,000 C) 10,000 D) 100,000 E) one million

Q: The temperature of the photosphere is about A) 3,200 K. B) 5,800 K. C) 11,000 K. D) one million K. E) ten million K.

Q: Unlike the nuclear reactions in the Sun, everyday chemical reactions involve only the electromagnetic forces.

Q: Without the strong nuclear force, the universe would be made only of hydrogen.

Q: Although protons repel each other at a distance, they will actually bind if they come close enough together.

Q: Most of the neutrinos given off by the Sun are changing form in the eight minutes before they reach us.

Q: The Solar Neutrino Problem is that we observe more neutrinos than predicted.

Q: Solar neutrinos take a little more than eight hours to get from the Sun's core to Earth.

Q: The proton-proton cycle converts all of the mass of the four hydrogen atoms into pure energy.

Q: In the proton-proton chain, helium atoms are fused into hydrogen.

Q: The Sun produces energy by fusing hydrogen into helium.

Q: During the fusion process, mass is converted into energy.

Q: The solar neutrinos observed on Earth come from the hot spots in the corona.

Q: The Sun is actually more luminous at sunspot minimum than at maximum.

Q: The solar corona is best studied using X-ray telescopes.

Q: Although sunspots are cooler areas in the photosphere, when they increase in number that tells us the Sun is becoming more active.

Q: Prominences are extensions of the solar magnetic fields above sunspots.

Q: The current sunspot cycle is the most active in a century.

Q: The prolonged period of few sunspots between 1645 and 1715 is known at the Maunder Minimum.

Q: Observations of sunspots at different solar latitudes prove that the Sun, like the gas giants, rotates differentially.

Q: The sunspot cycle averages about 11 months.

Q: Sunspots usually come in pairs of north and south magnetic poles.

Q: A typical solar flare lasts only a few days.

Q: The Sun's magnetic field is very weak compared to Earth's.

Q: The photosphere is the coolest layer close to the Sun, for the radiation of visible light allows it to cool off efficiently.

Q: The solar wind is constantly removing mass from the Sun.

Q: The solar corona is much cooler than the Sun's surface, hence we must wait for a total solar eclipse to glimpse it with the naked eye.

Q: The proton storms in the solar wind travel at almost the speed of light.

Q: The chromosphere is faint because of its low density.

Q: The bright photosphere is much hotter than the faint corona.

Q: The final step in transporting energy to the surface of the Sun is via convection.

Q: The granules in the photosphere are about as big as Texas, or around 1,000 km across.

Q: Granulation is the most obvious proof of solar convective energy transport.

Q: The Sun's average density is about the same at Jupiter's, suggesting a similar composition.

Q: The solar constant refers to that fact that the Sun's luminosity has remained unchanged in the age of the solar system.

Q: The Sun's structure is uniform throughout its interior, with no evidence of different layers.

Q: The Sun's radius is one astronomical unit by definition.

Q: The thickness of the photosphere is about 100 times the diameter of the Earth, and large sunspots are larger than our whole planet.

Q: Inside the Roche Limit A) large moons are torn apart. B) is where large moons form. C) ring systems cannot exist. D) there is a gap in a planet's magnetic field. E) hydrogen can only exist in its liquid metallic form.

Q: The Cassini Division is a gap in Saturn's rings caused by A) Saturn's excess heat. B) two shepherding moons. C) Saturn's magnetic field. D) gravitational interaction with Mimas. E) the icy ring particles melting.

Q: What best explains the darkness of the rings beyond Saturn's? A) The sunlight is much fainter out there. B) old, sooty debris and radiation darkening C) Water ice reflects light poorly at the low temperatures beyond Saturn. D) Rocky debris doesn't reflect as well as water ice. E) They are pieces of captured comets.

Q: When Saturn is at Equinox, its rings will A) double the planet's brightness. B) lie in the plane of the ecliptic. C) contract closer to the planet's surface. D) appear face-on to the earth. E) lie perpendicular to the plane of the ecliptic.

Q: Which statement about Jupiter's rings is true? A) They are larger than Saturn's, but darker. B) They lie inside Jupiter's Roche Limit. C) They are made, in part, of material ejected by Europa's volcanoes. D) They are dark because their ices are dirtier than Saturn's. E) They were discovered by Galileo at the same time he discovered the moons.

Q: Why are the rings of Saturn so bright? A) They are made of frozen metallic hydrogen. B) They are made of glassy beads expelled by the volcanoes of Enceladus. C) They are made of metallic iron, never rusted by exposure to oxygen. D) Light reflected off of gigantic Titan reinforces the sunlight. E) They are made of young, fresh water ice.

Q: For a moon the same density as its planet, the Roche limit lies at ________ times the radius of its planet. A) 1.4 B) 2.5 C) 3.6 D) 5.2 E) 7

Q: Which moon of Saturn shows the largest impact crater, relative to its size? A) Titan B) Callisto C) Mimas D) Miranda E) Enceladus

Q: What statistic below has changed the most in the last decade? A) the masses of the Galilean moons B) the compositions of moons of Uranus C) the rotational period of the Jovian moons D) the densities of the larger moons E) the number of known Jovian moons

Q: Which Jovian moon shows the most diverse terrain, suggesting a violent impact broke it into many pieces, some of which reformed it as a jumbled puzzle? A) Io B) Ganymede C) Enceladus D) Miranda E) Triton

Q: The brightest and probably youngest surface of any moon of Saturn belongs to A) Titan. B) Tethys. C) Mimas. D) Enceladus. E) Iapetus.

Q: Voyager 1 was unable to image Titan's surface because A) of "smog" in Titan's atmosphere. B) of Titan's high reflectivity. C) the moon was in shadow during the mission. D) the cameras were damaged by Saturn's magnetic field. E) volcanic activity spewed sulfur clouds, obscuring the surface.

Q: The erupting geysers of nitrogen gas on Triton A) can be viewed by the Hubble Space Telescope. B) are caused by a not yet determined internal energy source. C) produced the large liquid oceans. D) are increasing the moon's rotation rate. E) produced the frozen nitrogen surface.

Q: What is true of Titan's atmosphere? A) It is similar to Earth's in composition and density. B) It is primarily hydrogen. C) It is oxygen rich. D) It was discovered by the Voyager 1 spacecraft. E) It has produced a runaway greenhouse effect.

Q: The grooves and ridges on Ganymede are thought to A) be due to crustal tectonics motion (plate tectonics) B) have formed within the last thousand years. C) have grown considerably larger since the Voyager spacecraft discovered them. D) be part of an ongoing volcanic process. E) be due to the moon's rapid rotation.

Q: The atmosphere of Titan is composed mostly of A) oxygen. B) methane. C) carbon dioxide. D) hydrogen. E) nitrogen.