Review Material
This is meant to be a resource for doing homeworks, reviewing lecture material and studying for exams for ASTR100. This is meant to supplement your usual studying and lecture attendance. For mathematical problems, I strongly encourage that you practice doing the math without a calculator. If necessary, round numbers to get approximate answers, or try to take advantage of using ratios. It is necessary to note, however, that most of these problems were not created with nice, easy-to-calculate-in-your-head numbers, so it may be necessary to occasionally use a calculator. I would expect that some of these problems would be a little bit tricky for you to do on an ASTR100 exam - particularly those that ask you to derive equations, etc. So if you don't understand everything, don't panic! If you have any questions about any topics or problems (such has how you do a problem, or what the answer is), email me, James Keane at jamestuttlekeane@gmail.com. Good luck! EDIT: Two other ASTR100 TA's (Lauren Woolsey and Kenny Melville) have also created their own study worksheets or study guides. I have added these to the "Attachments" segment at the bottom of this page. The #1 Tip: For any equation or mathematical based problem, be able to understand ratios and scaling relationships. While you may very likely be asked to numerically calculate out an answer from an equation (such as to calculate out the volume of a sphere with 4/3*pi*r^3), what's more beneficial for you to understand, and what will be on the exam more is for you to realize that it's not important to actually calculate out these equations to gain beneficial knowledge. What's more important is that you realize, for instance in our volume of a sphere example, that the volume scales with the radius cubed. This will often simplify your math, and give you just as good as an answer. A good example is from HW#3, problem 58. Dr. McGaugh's ASTR100 website: http://www.astro.umd.edu/~ssm/ASTR100/. Go here for other review material, assignments and homework solutions! Gravity
EQUATIONS TO KNOW: Newton's Law of Gravity
1. How does the force of gravity between two objects, A and B, change if... a) I double the Distance between A and B? b) I put A three times as close to B? c) I make A five times more massive? 2. How to satellites (or moons or planets) orbit other objects? (Or in other words, what's the other force that's preventing a satellite from just falling into a planet because of gravity? 3. Using a ratio, calculate how much you would weigh on... a) The Moon (Radius of the Moon ~ 0.3 Earth Radii) (Mass of the Moon ~ 0.01 Earth Masses) b) Pluto (Radius of Pluto ~ 0.2 Earth Radii) (Mass of Pluto ~ 0.002) c) Jupiter (Radius of Jupiter ~ 11 Earth Radii) (Mass of Jupiter ~ 320 Earth Masses) 4. Astronauts in space... a) Calculate the force of gravity at an altitude of 300 km above the Earth, compared to the force of gravity at the Earth's surface. b) Astronauts always appear to be floating in space (Example). Using your answer to part a), reason why this is NOT because there is a lack of gravity in space. c) Since astronauts don't float due to a lack of gravity, why do they float? Kepler's Laws EQUATIONS TO KNOW: Kepler's Third Law
Newton's Version of Kepler's Third Law Intermediate Version of Kepler's Law (derived in problem #5) 1. Under which circumstances can you use Kepler's original Third Law, as opposed to Newton's Version of Kepler's Third Law? a) For calculating the orbital period of Mars around the Sun? b) For calculating the semi-major axis of one of Jupiter's Moons? c) For calculating the orbital period of an extrasolar planet around a star other than the Sun? 2. What units must you use for... a) Kepler's Original Third Law b) Newton's Version of Kepler's Third Law 3. Calculate the orbital period of an asteroid discovered orbiting the Sun at a semi-major axis of... a) 4 AU b) 1/4 AU c) 25 AU 4. Calculate the semi-major axis of an asteroid discovered orbiting the Sun with a period of... a) 1000 Years b) 8 Years c) 1/64th of a Year 5. Using ratios, convert Newton's Version of Kepler's Third Law into an intermediate equation between Newton's Version and Kepler's Original Version - such that it takes into account the total mass of the system. (ANSWER) 6. (HARD) Calculate the mass of Saturn, by observing the period and semi-major axis of one of it's moons, in two ways. (You may need a calculator for this problem) Important information: Semi-Major axis of Titan is 1,200,000 km. Orbital Period of Titan is 16 days. Important information: 1 AU = 150,000,000 km. 1 Solar Mass = 2.0 x 10^30 kg a) Convert into the appropriate units for Kepler's Original Third Law, and use Kepler's Original Third Law to solve for Saturn's Mass b) Convert into the appropriate units for Newton's Version of Kepler's Third Law, and use Newton's Version of Kepler's Third Law to solve for Saturn's Mass 7. (HARD) Using the Distance-Velocity-Time equation (D=r*t), and the Circumference of a Circle (2*pi*r), and Newton's Version of Kepler's Third Law to derive an equation for the the circular orbit velocity of a satellite as a function of the Mass of the planet it's orbiting (M), and the distance from the planet's center (r). 8. Using the equation that you found in problem 7), calculate how fast the International Space Station must move to stay in Earth Orbit. Important Information: Earth orbit = 300 km above the Earth's Surface. Earth's Radius ~ 6,380 km. 9. Draw a picture of a comet's orbit around the Sun, to approximate scale. Label the Semi-Major Axis, the Major-Axis, the Minor-Axis, Aphelion, Perihelion, the two Foci, the Sun, and be sure to draw an orbit with an appropriately large eccentricity (which would be typical for a comet). 10. Using Kepler's 2nd Law, explain why object move fastest at Perihelion, and slowest at aphelion. 11. Using Kepler's 2nd Law, where do satellites spend most of their time orbiting: near aphelion or near perihelion? 12. What shape are all normal orbits? How is this different then the shapes of orbits in previous cosmologies (such as the geocentric model)? Conservation Laws EQUATIONS TO KNOW: Kinetic Energy
Newton's LawsGravitational Potential Energy (on the scale of planets) Gravitational Potential Energy (on the scale of people) 1. There are four main quantities in nature that are conserved. Briefly (1 or 2 sentences) explain each: a) Conservation of Energy b) Conservation of Mass c) Conservation of Momentum d) Conservation of Angular Momentum 2. When an ice skater is in a spin, she pulls in her arms, which causes her rotational speed to increase. Which conservation law explains this the best? 3. When a bowling ball hits a set of pins, the bowling ball slows down and the pins go flying. Which conservation law explains this the best? 4. An infrared lamp shines onto a table, causing the table to heat up. Which conservation law explains this the best? 5. As it turns out, Einstein showed that the conservation of mass and the conservation of energy are related by his famous expression: E=mc^2. a) Using this equation, calculate the energy of a nuclear bomb converting 1 kg of nuclear material into pure energy. b) Using this equation, calculate how much mass must be being turned into energy in the Sun per second, if the Sun is emitting 4 x 10^26 joules per second. c) The Sun is expected to continue producing energy for another 5 billion years. Using this, calculate how much mass the sun will lose due to fusion in that time. 6. A 1 kg ball is being dropped from the top of a 50 meter building. a) Set up an equation showing the conservation of kinetic and potential energy (on the scale of people) for before you drop the ball, to the time it impacts. b) Calculate the velocity at which the ball will hit the ground, assuming that the acceleration due to gravity (g) on Earth is 10 m/s^2 7. (HARD) Using the same technique as in question 6), calculate the velocity at which I would have to launch a rocket for it to reach an altitude of 1 km. Assume the mass of the rocket is 5 kg. 8. Derive an equation for the escape speed for a planet with radius, R, and mass, M, by using the conservation of Kinetic Energy and Gravitational Potential Energy (planet scale). Note: to do this, assume that the rocket starts with some velocity (escape velocity), on the surface of the Earth (R), and that it ends up at a distance of infinity, with no velocity. (ANSWER) 9. Compare the equation for the escape speed to the equation derived for the circular orbit velocity in Kepler's Laws, question 7. 10. In the in class demonstration of a pendulum in motion, we saw that the pendulum will never go higher than its starting position, no matter what sort of obstacles are placed in its way (such as that peg). What conservation law was this proving? EQUATIONS TO KNOW: Newton's Second Law
1. What is Newton's... a) First Law? b) Second Law? c) Third Law? 2. What are the units of Force - as determined from Newton's Second Law? (Deterimine the units of Force by looking at the units of everything on the right hand side of Newton's Second Law) 3. A rocket flying in space works based primarily off which of Newton's Laws? 4. A bullet passing through a wooden wall is an example of which of Newton's Laws? 5. Which of the following is not an acceleration? Explain your reasoning for each case. a) A car going from 0 to 60 mph in a few seconds. b) A car going at a constant speed in a straight line. c) A car slowing from 60 to 0 mph in a few seconds. d) A car staying at a constant speed, but turning around a circular track. 6. As someone who has some given mass, in the gravitational field of the Earth, there is some Gravitational Force pulling me towards the center of the Earth. However, as all of you know, no one is just falling through the Earth to the Core. Explain why using Newton's Third Law. (What reactive force is balancing out gravity?) Terrestrial Planet: Geology EQUATIONS TO KNOW: Density
1. Looking up online, or in your text, give an approximate density for the following materials... a) Air b) Liquid Water c) Rocks d) Metal 2. (TRICKY) The Earth has a density of 5.5 g/cm^3. Convert this density into kg/m^3. 3. Looking at the density of the Earth, and comparing it to your answers for problem 1), what do you think is the bulk make up of the Earth (Air, Water, Rocks or Metals)? Why? 4. If I double the Earth's radius, but kept it the same mass, how would it's density change? 5. If I quadrupled the Earth's mass, but kept it the same density, how much larger or smaller would the Earth's radius have to become? 6. This linked image shows the cratering rate in the solar system, as a function of time (it also has information about lunar features labeled on it, but you can ignore those for now). Using this, explain why planets with old surface would have more craters than planets with young surfaces. 7. One way that the surfaces of planets can change is by volcanoes exploding and resurfacing nearby terrain with lava. List 4 other different methods by which a planet's surface can be erased, formed, or reshaped (thus reshaping that cratering clock from problem 6). 8. Put these terrestrial planets - Mercury, Venus, Earth, and Mars - in order of... a) Distance from the Sun (from closest to furthest) b) Radius (from smallest to largest) c) Mass (from smallest to largest) d) Density (from smallest to largest) e) Age of their surface (from oldest to youngest) 9. Why does the Earth have the youngest surface of all the terrestrial planets? What's different about Earth, as compared to say Venus, that could have cause this difference. 10. MERCURY a) Scarps are a prominent feature of Mercury. What are they and where do they come from? b) Mercury has a magnetic field. Why is this strange? 11. VENUS a) Why is Venus sometimes called Earth's twin? b) What's special about Venus's rotation? 12. EARTH a) Explain why the Earth has a magnetic field, and where it comes from. b) What causes Aurora? c) Explain Plate Tectonics. 13. MARS a) What is Valles Marineris? Why is it significant? b) What is Olympus Mons? Why is it significant? c) Does Mars have plate tectonics? If so, how is it different from Earth? d) Mars has polar ice caps. What are they made up of, and why? 14. THE MOON a) Of the other four terrestrial planets, which one is the Moon most like? b) What are Mare? How did they form? c) What are the Highlands? d) Which are the oldest parts of the Moon - the Highlands or the Mare? e) What's special about the Moon's orbital period, and rotational period? How are they related? f) What phase is the Moon in today? (ANSWER) 15. A lot of the terrestrial planets have some internal heat. Where does this come from? Terrestrial Planet: Atmospheres 1. MERCURY & THE MOON
a) Mercury and the Moon lack appreciable atmospheres. Why? 2. VENUS a) What is the primary constituent of Venus's atmosphere? b) How does the surface temperature of Venus compare to that of Earth's? c) How does the atmospheric pressure on the surface of Venus compare to that of the Earth's d) Why is Venus's atmosphere so hot? (Explain in detail) 3. EARTH a) What are the top constituent of the Earth's atmosphere? b) Explain the Greenhouse Effect in detail. Why is it important that the Earth have a natural greenhouse effect? What proof is there of an artificial greenhouse effect? c) What's the most important, natural, greenhouse gas? d) Explain the Carbon Cycle. e) Where did the Earth's water likely come from? 4. MARS a) What is the primary constituent of Mars's atmosphere? b) How does the surface temperature of Mars's atmosphere compare to that of the Earth's? c) How does the atmospheric pressure on the surface of Mars compare to that of the Earth's? 5. Why don't any of the terrestrial planets have Hydrogen or Helium as a primary component in their atmospheres? (In the universe, those are the two most predominant elements, so it might seem weird why we don't have any.) The Jovian Planets 1. Put these Jovian planets - Jupiter, Saturn, Uranus, Neptune - in order of... a) Distance from the Sun (from closest to furthest) b) Radius (from smallest to largest) c) Mass (from smallest to largest) d) Density (from smallest to largest) 2. Sometimes Uranus and Neptune are referred to as "Ice Giants." Explain why this is, and how they are different than the regular Jovian Planets (Jupiter and Saturn). 3. Using this image, which shows the size of a gas planet, as a function of mass. (Fig. 8.2 in the text may also help). a) Why is there a maximum size for a gas planet? b) Why is Saturn close to the size of Jupiter, even though it isn't as massive? 4. The Jovian planets (with the exception of Uranus), output more energy than what they receive from the Sun. Where does this energy come from? 5. Why do the Jovian planets have (usually) very strong magnetic fields? Where do the fields come from, and how do we observe them? Moons, Asteroids, Comets, & Dwarf Planets 1. Io and Enceladus are two examples of moons of Jovian planets that have active, volcanic geology. Explain how the two systems differ. 2. Phobos is one of the two moons of Mars (IMAGE), yet is only 17 km across. Using this, and by looking at the image, what do you think is the origin of Phobos? Explain your answer. 3. Saturn's moon Titan is an extremely fascinating world - primarily for the fact that it has a substantial atmosphere. a) Why is it weird that Titan has an atmosphere? Do any other moons in the solar system have atmospheres, and if so, which ones? b) What is the composition of Titan's atmosphere? 4. Io and Europa are two Jovian moons that are geologically active. What is the source of their active geology (i.e., why are they internally hot)? 5. Using cratering rates, rank these five moons (Io, Europa, Ganymede, Callisto and the Earth's Moon) in terms of surface age - from young to old. 7. What's unique about the orbit of Neptune's moon: Triton? 8. What is the general composition of the Jovian Moons? 9. Where are most asteroids in the Solar System? 10. What is the general composition of an asteroid? 11. Assume we have an asteroid with a density of 3.0 g/cm^3, and a radius of 15 km. If it were to slam into the Moon with a velocity of 11 km/s, calculate the kinetic energy of this impact. Compare this energy to the energy of an atomic bomb detonation with an energy of 4.2 x 10^15 Joules (1 megaton of TNT). 12. What are two pieces of evidence that we have showing that the Dinosaurs were killed off by a massive asteroid impact? 13. Let's say we have one asteroid and one comet, that have the same mass. Thinking about density, which of these would be the larger object? 14. Explain EVERY aspect of this image of a comet's orbit and the evolution of it's tail. Be able to draw and explain this! a) What is the Coma? b) Why do the Tails and Coma start forming around the orbit of Jupiter? c) What are the two different types of tails for a comet, and how do they differ? 15. (HARD) The Tunguska Event is thought to be an "air burst" event, where a comet detonated in the upper atmosphere. It detonated with an energy of 30 megatons (1 megaton = 4.2 x 10^15 Joules). a) Using the equation for kinetic energy equation, calculate the mass of the comet, if it impacted with a velocity of 20 km/s. b) If the comet was a perfect sphere, and had a density of 1,500 kg/m^3, calculate the size of this comet. 16. Do a Google search. How many Dwarf Planets are there currently? 17. What are the current IAU requirements for a planet to be a planet? 18. Looking at the requirements for a planet, why do we no longer consider Pluto a planet? 19. Where do most comets come from? 20. What are the Oort Cloud and Kuiper Belt? Explain in terms of shape, location, and what they're made up of. Solar System Formation 1. Explain, in excruciating detail, EVERY step of the Solar Nebula Hypothesis! (For instance, explain everything in this image)
2. What was the composition of the Solar Nebula? 3. Most of this mass went into the Sun, with only a small portion went into planets. Looking up in your text, calculate the total mass in all eight of the planets. Compare this to the Sun. What percent of the Solar System's total mass is in the planets? 4. Why did the Solar Nebula speed up its rotation as it collapsed early in the Solar System's formation? 5. What is the Frost Line? (Sometimes called the Ice Line.) Be able to draw and explain this diagram. 6. Using the Frost Line, explain why there are no Jovian planets up close to the Sun. 7. Using the Frost Line, explain why the Jovian planets are more massive than the Terrestrial planets. 8. Using the Frost Line, explain why a comet stuck only in the inner solar system (say, near the Earth), would not last long. 9. Explain how the following observations are evidence for the Solar Nebula Hypothesis. a) All of the major planets orbit in very nearly the same plane. b) All of the major planets' orbits have very low eccentricities. c) The Frost Line (i.e., Terrestrial planets up close to the Sun, Jovian planets far away) 10. In other solar systems we observe a LOT of extrasolar planets that are so called "Hot Jupiters." a) What are Hot Jupiters? b) Should we expect Hot Jupiters in a solar system formed via the Solar Nebula Hypothesis? c) Thinking about the detection methods for extrasolar planets, what's one reason we detect so many Hot Jupiters? The Electromagnetic Spectrum EQUATIONS TO KNOW: Wavelength & Frequency
Energy of Light Doppler Effect 1. The electromagnetic spectrum can be broken into various different individual bands: radio, infrared, visible, ultraviolet, x-ray, and gamma ray. Answer the following questions about the E&M spectrum: a) Rank the different E&M bands in order of: Longest to Shortest Wavelength b) Rank the different E&M bands in order of: Largest to Smallest Frequency c) Rank the different E&M bands in order of: Largest to Smallest Energy 2. The optical spectrum only makes up a small fraction of the total E&M spectrum. The optical spectrum can be broken down into different colors: red, orange, yellow, green, blue, indigo and violet (remember the elementary school acronym of ROY G BIV?). a) Rank the bands of the visible spectrum in order of: Longest to Shortest Wavelength b) Rank the bands of the visible spectrum in order of: Largest to Smallest Frequency c) Rank the bands of the visible spectrum in order of: Largest to Smallest Energy 3. (TEDIOUS - BUT IMPORTANT!)Below is an incomplete table of the Wavelength, Frequency, Energy, and Speed of different types of light. Complete the table! While the given units may NOT be in SI units, I want all of your answers to be in SI units (i.e., meters, Hz, Joules, etc.). By looking at your results, write down which part of the Electromagnetic Spectrum, such light would be in. WAVELENGTH FREQUENCY ENERGY SPEED Portion of the Electromagnetic Spectrum 1. 1 m 2. 100 Hz 3. 2 x 10^-20 J 4. 400 nm 5. 10^20 Hz 6. 1 eV (electronvolt) 7. 21 cm 8. 10^14 Hz 9. 1 THz (terahertz) 10. 1 Angstrom 4. Compare X-Rays to Infrared... a) Which has a higher wavelength? b) Which has a higher frequency? c) Which has a higher energy? d) Which has a higher speed? 5. Light can be expressed as both a wave and a particle. What is this principle called? What is a particle of light called? 6. (TRICKY - BUT IMPORTANT) 656.28 nanometers is a very well defined emission line of hydrogen (H-alpha line). Let's say we're observing a number of different stars by looking at this line. Use the Doppler Effect to answer the questions below: a) We observe a star with an H-alpha line of 650 nm. Is this star moving towards us, or away from us? b) We observe a star with an H-alpha line of 650 nm. Is this star's light being redshifted or blueshifted? c) Using the Doppler Effect equation, calculate the line of sight velocity of this star (i.e., how fast is it moving towards us or away from us). 7. (HARD) Escaping Neutron Star! Some neutron stars have been observed to be moving so fast that they will actually escape the Milky Way Galaxy. a) Knowing that the mass of the Milky Way is 5 x 10^11 solar masses, and that the Neutron star started 26,000 lightyears away from the center of the Milky Way, calculate the escape velocity of the Milky Way from that distance. Presume that you can approximate the Milky Way has a "point mass" - and that you can use the equation you derived for problem #8 in "Conservation of Energy" to calculate the escape speed. b) Assuming that this star is flying exactly away from us, at the speed you calculated in part a), and assuming that we're observing a spectral line with an 'at-rest' frequency of 3000 MHz, calculate out the frequency of this spectral line that we'd see from the moving star. 8. There are four ways that light can interact with matter. What are they, and in one sentence, explain each. Spectra 1. There are three different types of spectra: continuum, absorption and emission. Explain, in detail, what causes each, and how do they differ in appearance. (PARTIAL ANSWER 1, PARTIAL ANSWER 2) 2. What type of spectra would we see in the following circumstances... a) The hot filament (a heated piece of metal) of a lightbulb? b) The Sun? c) A neon light (where neon gas is heated up by an electric current)? d) The Moon? 3. Explain how observing spectra can tell us information about the following things: a) The composition of an object b) The temperature of an object c) The motion of an object Telescopes EQUATIONS TO KNOW: ANGULAR RESOLUTION 1. There are two major classes of telescopes: refraction and reflection telescopes. Answer the following questions about them. a) Draw a rough schematic of each type of telescope. b) Which type uses mirrors? Which type uses lenses? c) Which type was the first to be built? d) What are the disadvantages of a refraction telescope? 2. What is "seeing" in astronomy terms? 3. Give two reasons why we send telescopes like the Hubble and Spitzer into space? 4. What parts of the electromagnetic spectrum can penetrate our atmosphere (and thus enable us to build ground based observatories)? 5. Light collecting area and angular resolution are the two biggest components of any telescope. Explain what we mean by each term, and specifically why astronomers want larger telescopes because of it. 6. If we have two reflecting telescopes, with mirrors of equal size, but one observes in the radio, and one observes in the infrared, which will have better angular resolution? 7. The Hubble Space Telescope has a primary mirror 2.4 meters in diameter, and it observes in the optical (~500 nanometers). Calculate the angular resolution of Hubble in arcseconds. 8. Telescope A has a diameter of 2 meters. Telescope B has a diameter of 4 meters. They both observe in the same wavelength band. a) How does the angular resolution of Telescope B compare to Telescope A? b) Telescope A observes a distant galaxy for 20 minutes. How long would it take Telescope B to observe the same galaxy and collect the same amount of light? 9. How is angular resolution different than zoom? 10. What is adaptive optics? Extrasolar Planets 1. Go to http://planetquest.jpl.nasa.gov/. How many extrasolar planets have we detected so far?
2. The main way we have detected extrasolar planets is by the "Doppler Method." How does this work? 3. The Doppler Method has a selection effect, in that it is more likely to detect large planets, up close to their stars. a) What are these planets called? b) Why is there this selection effect? c) Does this detection of Jupiter size or larger planets, up close to their stars, jive with the Solar Nebula hypothesis? d) If an extrasolar planet were orbiting in a plane perpendicular to our line of sight, would the Doppler Method allow us to detect it? Why/Why not? 4. A second detection method is the "Transit Method." How does this work? 5. The Transit Method ALSO has a selection effect, in that it is more likely to detect large planets, up close to their stars. Why is this? 6. What are pulsar planets? 7. Let's say we're trying to observe the Earth from a neighboring star system, with the Transit Method. By calculating out the cross-sectional area of the Sun, and the Earth, and comparing the two, determine by what percent would the sun's brightness drop during a transit. Luminosity and Black Bodies EQUATIONS TO KNOW: STEFAN-BOLTZMANN LAW ( sigma = 5.67x10^-8 W/m^2/K^4 )
BRIGHTNESS/LUMINOSITY WIEN'S LAW ( b = 2.9x10^6 nm K ) 1. The Sun has a peak wavelength of 502 nanometers. Using Wien's Law, calculate the surface temperature of the Sun.
2. (TRICKY) The Sun has an angular size of 32 arcminutes (60 arcminutes = 1 degree), and is 1.5x10^11 meters away. Using this, calculate out the radius of the Sun. 3. Using your answer from 1) and 2), calculate the luminosity of the Sun (or if you can't do #2, look up the Sun's radius) 4. Star A has a peak wavelength twice that of Star B. Which star is hotter, and by how much? 5. Star C is four times as hot as Star D, but they have the same radius. How do their luminosities compare? 6. If the Sun were to suddenly become 1/4th as bright, but remain the same surface temperature, how would it have changed in size? 7. The brightness measured from 1 meter away from a light bulb is 10 W/m^2. How would the brightness changed if... a) I moved to three meters away from the light bulb? b) I moved to 0.5 meters away from the light bulb? 8. A lightbulb filament glows with a luminosity of 1 W. If the luminosity increased to 16 Watts, how did the temperature of the filament change? How would its color of changed? 9. Wien's law technically only applies to "black bodies." What are black bodies? What are the spectra of black bodies like (absorption, emission, continuum)? The Sun: Nuclear Fusion EQUATIONS TO KNOW: ENERGY-MASS EQUIVALENCE 1. Why does the sun shine? 2. Draw a diagram of the Proton-Proton Chain (which is the type of fusion going on inside of the Sun). 3. (HARD) In the Proton-Proton Chain, 4 hydrogen nuclei (protons), turn into 1 helium nucleus. Look up online the mass of a single proton, and the mass of helium. a) What is the mass difference between 4 protons and 1 helium? b) Using the energy-mass equivalence equation (kudos to Einstein), calculate the energy released by one proton-proton chain reaction. c) The Sun has a luminosity of 3.8x10^26 Joules/Second. Calculate out how many reactions must go on in the Sun, each second, to produce the Sun's luminosity. d) Assuming that the Sun will keep this same luminosity over its entire lifetime, in addition to the assumption that the Sun will fuse 1/10th of a Solar mass of hydrogen into helium over it's lifetime, calculate out how long the Sun will live. 4. During the Proton-Proton Chain, neutrinos are produced. What are neutrinos, and why are they significant? 5. The photons (energy) produced by fusion in the Sun's core struggle to reach the surface of the Sun in a "random walk." What is this? 6. SOLAR STRUCTURE: Draw a schematic of the Sun's structure - including the following things: Core, Radiative Zone, Convective Zone, Photosphere, Chromosphere, Corona. Give a one to two sentence description of each layer. (PARTIAL ANSWER) 7. See this image of a Sunspot: IMAGE. a) What is a Sunspot? b) What causes Sunspots? c) Label the two parts of the Sunspot. d) Outside of the Sunspot, we see Granulation. What does this mean? 8. What's strange about the Solar Corona, compared to other layers of the Sun's atmosphere? 9. What is the composition of the Sun? How will the composition of the Sun change as the Sun ages? 10. What is the Solar Cycle? What is Solar Maximum and Solar Minimum? 11. Helioseismology allows us to explore the interior of the Sun by looking at the propagation of sound waves in the Sun. What have we learned from this technique? 12. Google some information on the Sun. What are we in right now - Solar Minimum or Solar Maximum? Is there anything strange going on with the Sun's current solar cycle? 13. Solar Flares and Coronal Mass Ejections are forms of magnetic disturbances on the Sun. How do they effect us on Earth? |
