Table of Contents

The Sun
Solar Model

Intro to Astronomy

Equitorial Coordinates
Understanding the Seasons

Time & Its Measurement


Solar & Lunar Eclipses

The Solar System

The Earth

The Moon

Mecury, Venus, Mars

The Outer Planets

Solar System Debris

Evolution of Stars

Intersteller Matter

Sky Literacy

The Sun

Can You Answer the Following Questions?


1. Supply the following information about the sun:
    a. distance from earth .................................... _______________
    b. diameter .................................................... _______________
    c. volume (in comparison to earth) ................ _______________
    d. mass (in comparison to earth) .................... _______________
    e. density ....................................................... _______________
    f. "surface" temperature ................................ _______________
    g. core temperature ....................................... _______________


2. The two most abundant elements which are contained within the sun are _______________
    and _______________. Those elements with an atomic number greater than two can be
    collectively referred to as _______________.

3. All elements contained within the sun are found in the _______________ state. In fact most
    of the material is in the form of a _______________.

4. The sun powers itself through a conversion of _______________ into _______________.
    Albert _______________ laid the foundation for astrophysicists to speculate upon how the
    sun produces its own energy.

5. The nuclear reaction which powers the sun is referred to as the ______________ reaction.

6. Essentially, during this process four _______________ (atoms) fuse via a distinct series of t
    reactions to produce a helium nucleus. Since a helium nucleus, which is composed of two
    _______________ and two _______________, weighs MORE/LESS (circle one) than
    four hydrogen protons, some _______________ has been converted into
    _______________. The amount of matter converted into energy is 0.7 percent per reaction.

7. Even though approximately _______________ million tons of matter are annihilated every
    second, the chances that a particular hydrogen proton will go into a reaction at any given
    moment is extremely SMALL/LARGE (circle one). It will take about 10 billion years for
    approximately _______________ percent of the original hydrogen in the core to be
    converted into helium.
8. The energy created in the core of the sun takes on the order of ____________________
    years to travel through its interior and finally escape from the "surface." Thereafter, only about
    _______________ minutes elapses before that same energy reaches the earth, 93 million
    miles (150 million km) away.

9. During its passage from the core to the surface, the energy per photon INCREASES/
    DECREASES (circle one). During this same period the number of photons carrying this
    energy towards the surface INCREASE/DECREASE (circle one).

*10. By-products of the proton-proton reaction are high intensity gamma radiation, positrons
    (electrons with a positive charge), and n        . These latter "particles" have a HIGH/LOW
    (circle one) probability of reacting with matter and probably possess no mass. Gamma rays are
    almost immediately absorbed and reemitted as x-rays, while positrons are annihilated on the
    spot by free electrons and changed into energy.

*11. Ray Davis a chemist at the Brookhaven National Laboratory in New York state has built a
    _______________ detector about one mile underground in the Homestake Gold Mine near
    Lead, South Dakota. In essence he has filled a 100,000 gallon container with
    perchloroethylene C2Cl4 (dry cleaning fluid) in the hopes of changing an isotope of chlorine
    (37) into an isotope of (detectable) radioactive argon. The nuclear reaction is triggered by a
    neutrino which is produced by a variant of the proton-proton reaction in the sun. Based upon
    the rate of energy escaping from the sun, it is possible to calculate the amount of matter being
    annihilated, and therefore the number of neutrinos being produced, as well as the probability
    that these neutrinos will react with the fluid in the tank. Davis' results have consistently shown
    that the number of radioactive argon atoms being produced in his tank

12. The sun is a stable star because throughout its various layers the force of gravity created by its
    mass balances the outward pressures resulting from its energy production. This is termed


13. The temperature of an object is a direct function of the average ____________________
    (½mv²) which the atoms and molecules of that body possess. At absolute zero, all
    _______________ motion ceases. The absolute scale for measuring temperature is called the
    _______________ scale and each degree equals _______________ Fahrenheit degrees.

14. The three types of energy transportation mechanisms are known as _______________,
    _______________, and _______________.

15. When warmer gases or fluids move in bulk into cooler regions, that type of energy transfer is
    said to be _______________. The warmer gases or fluids are less dense than the surrounding
    medium. This makes them _______________ (Think of a direction of movement) because they     obtain buoyancy with respect to their surrounding medium.

16. The handle of a metal spoon in a pot of soup soon becomes warm because heat is transferred
    through physical contact from one atom to another atom along the length of the spoon via

17. Energy which is transferred across a space from an emitter to an absorber without affecting the     matter in between is _______________ to that position. When you are warmed by a fire or the     sun, the energy being absorbed warms the skin by causing an increase in its molecular motion.     Virtually no energy goes into heating the matter in the space between you and the source.

18. The light that we see, as well as all of the energy of the electromagnetic spectrum, can be
    described as being either a _______________ or a _______________. For the purposes of
    energy transfer within the sun, it is best to think of the radiation traveling through this star as a

19. The three interior layers of the sun through which a photon of light must pass prior to escaping
    into space are called the _______________, the _______________ zone, and the
    _______________ zone. The sun produces its energy in the _______________ which
    comprises about 25 percent of its radius.

20. From the center of the sun's core through about 70 percent of its radius, the mechanism of
    energy transport is _______________.

*21. Throughout this zone mentioned in the last statement, energy is transported via the s of
    photons by electrons and the ____________________ (the detachment) of electrons from ions     by photons.

22. Throughout the last 30 percent of the solar interior, the dominant energy transportation
    mechanism becomes _______________. *The transition results from lower temperatures
    which allow electrons to begin to attach themselves onto the nuclei of atoms. Upcoming
    radiation excites and ionizes these atoms again with energy being absorbed in the process. This
    causes heat to be trapped at this level and temperatures to drop more slowly. The result is an
    increase in the temperature gradient above this level to the point where convection can occur.

23. At the sun's "surface" energy escapes and heads into space via the process of


If you have not done so already, read the section entitled "Magnetic Fields" in Session Five and
answer the questions pertaining to magnetic fields in Session Six before proceeding.

24. All of the visible effects which can be seen on the sun are directly related to

25. The solar magnetic field probably originates in the CORE/RADIATIVE ZONE/
    CONVECTIVE ZONE (circle one) of the sun's interior. It results from the flow of
    _______________ currents within this region and the _______________ of the sun, which
    may be more rapid than what is observed at the surface.

26. TRUE OR FALSE (circle one): The planets of our solar system all lie within the magnetic
    influences of the sun.


27. The light-emitting region of the sun, about 100 miles (160 km) in thickness is called the
    _______________. Above this layer, is a 1300 mile (2000 km) region of increasing
    temperatures called the _______________. This area emits light at certain discrete
    wavelengths, predominately as a result of the hydrogen atom. The least dense, but hottest
    portion of the solar atmosphere, easily visible during totality in a solar eclipse, is called the

*28. Through a telescope, the edge of the sun appears less bright than the center of the disk. This
    is termed ____________________ and results from our ability, to view only the upper regions
    of the sun's photosphere near the solar limb. These areas appear darker because they are
    WARMER/COOLER (circle one) than the lower levels of the photosphere.

29. Describe one safe method by which the sun can be observed in white light.

30. When viewing the sun through a telescope, it is considered foolish to use a dark absorbing
    filter. Telescopes _____________ the light of the sun and focus this hot, bright image near the
    position of the dark filter causing it to become hot. If the filter _______________, the observer     is likely to suffer permanent eye damage or even blindness. If you own one of these accessories,     THROW IT AWAY!!!

31. A highly resolved view of the photosphere reveals a speckled "surface" which is termed
    _______________. This phenomenon represents the end of the line for the energy
    transportation mechanism known as _______________. The brighter regions of these cells
    represent warmer gases which are moving ________________, while the darker cell
    boundaries are composed of cooler gases drifting _______________.


32. TRUE OR FALSE (circle one): Sunspots are considered to be storms on the photosphere of
    the sun.

33. In the convective layer of the sun ____________________ can become tangled and
    intensified. When this happens they can rise to the surface and cause a slowing of the convection     in that region. This WARMS/COOLS (circle one) that area causing it to EMIT MORE/LESS
    (circle one) energy. This makes the area appear LIGHTER/DARKER (circle one) than the
    surrounding region.

34. This phenomenon as noted in the last statement is called a _______________. Their numbers
    vary in a mysterious _______________ year cycle, which, if all magnetic considerations are
    taken into account, is really a _______________ year period.

35. Sunspots can last from _______________ to ______________ and in more mature
    examples possess a darker, central region called the _______________ and a lighter region
    termed the _______________. Temperatures are lower by about 2000 K (3600° F) in the
    darker regions.

36. Sunspots near the equator of the sun circuit the sun in a SHORTER/LONGER (circle one)
    period of time compared to sunspots at higher latitudes. The motion of sunspots proves not only     that the sun is _______________, but at different speeds depending upon the latitude at which
    the spot is found. This difference in the rate of spin of the sun at various latitudes is called
    _______________ rotation.

37. According to Babcock (1960) the _______________ rotation of the sun causes the magnetic     field lines to become stretched around the sun many times. Entanglement of the field occurs
    between 30 and 40 degrees north and south latitude. The field here becomes intensified and
    buoyant, causing it to rise to the surface, creating the _______________ that we see. Over a
    period of years, the regions of highest magnetic intensity gradually migrate towards the
    _____________ as the solar rotation winds up the field. The opposite fields eventually come
    together near the equator and are neutralized.

38. A sunspot group usually appears in two clumps. This indicates that they are bipolar which
    means that they normally contain regions of _______________ magnetic polarity.

39. During one sunspot cycle the leading spots of each hemisphere are of the SAME/OPPOSITE
    (circle one) polarity. During the next cycle, the polarities of the leading spots of each hemisphere     reverse themselves, thus making the true magnetic cycle of the sun equal to a period which
    averages _______________ years.

40. Sunspots may have some relationship to climate. The sun's output of energy is
    GREATER/SMALLER (circle one) during sunspot maximum and just the opposite during
    sunspot minimum. During the period between 1645 and 1715 (in regards to sunspot numbers)
    _________________________________________. This has become known as the
    _______________ minimum. Europe during this period (1400-1850) experienced climatically


41. A solid, liquid, or gas (under high pressure) when heated and made to incandesce (glow)
    produces a _______________ spectrum.

42. A rarefied gas when made to glow produces bright spectral lines at wavelengths distinctive
    only to that gas. This type of spectrum is called an _______________ spectrum.

43. A cool, rarefied gas found between a continuous source and an observer will produce an
    _______________ spectrum.

44. The name of the German physicist who formulated the three laws of spectroscopy mentioned
    above was Gustav K_______________ (1824-87).

45. According to the man in the previous question, a continuous spectrum can only be produced
    by a solid, liquid or _______________ (under pressure) which is heated to incandescence. The     pressures in the photosphere are HIGH/LOW (circle one) and WILL/WILL NOT (circle one)
    allow the continuum to be formed in the traditional manner. In the sun it is the loose attachment
    of an extra electron to the _______________ atom which is responsible for the formation of
    the continuum. When the extra electron attaches to form a negative ion, energy of varying
    wavelengths is ABSORBED/GIVEN OFF (circle one). This produces the continuum. When the     ion is ionized, just the opposite situation happens.


46. When white light enters a prism, it is dispersed into the rainbow of colors known as the
    _______________. An astronomical device which creates such an image, but with a high
    degree of resolution (clarity) is called a _______________.

47. When high resolution is obtained, it is noticed that dark _______________ lines are
    superimposed on the brighter background known as the _______________. These darker
    bands represent the fingerprints of the various _______________ which the sun or another star     contains.

48. Energy is absorbed by various atoms in the solar (level) _______________. The electrons of
    these atoms become ex _______________, jumping to specific orbital levels which absorb
    unique amounts of energy. Eventually, when the electron spontaneously returns to a lower
    energy state, it will em _______________ energy at the same intensity of absorption. The
    energy is absorbed unidirectionally, as it leaves the sun, but emitted randomly with respect to
    direction when the electron moves down the energy ladder. The result is a(n)
    _______________ line on the continuous spectrum where the solar energy of that specific
    wavelength has been subtracted.

49. Although most absorption lines are formed in the _______________ of the sun, a few, such
    as the hydrogen alpha line (6563 Å), and the H and K lines of ionized calcium are created in the     _______________. This latter region is transparent in visible light, but not at the wavelengths of     energy which are absorbed in this layer. If the layer is viewed in the light of one of these specific
    _______________ lines, the region can be isolated for observation. The type of astronomical
    instrument which can accomplish this is called a ____________________.

50. Satellite observations of the sun made in the u _______________ and
    x _______________ portions of the electromagnetic spectrum reveal HOTTER/COOLER
    (circle one) regions in the outermost solar level called the _______________. These areas are
    also less dense, so pressures are lower. Magnetic flux lines extend outward into space and carry     plasma away from the sun in these regions to create the ____________________. The
    features themselves are called c_______________ h_______________ (two words). .

51. There IS/IS NOT (circle one) a direct relationship between activity occurring at one level of
    the sun and activity occurring at a higher or lower level. In other words, does solar activity at
    one level influence activity in other levels?


52. Almost all features of the sun can be attributable to the action and interaction of the sun's
    plasma with its ___________________.

53. A _______________ results when a region of high magnetic intensity breaks into the
    photosphere to inhibit convection and cool down that region.

54. This magnetic influence extends far into the sun's corona where large arcs of gas can be made
    to incandesce and travel along the field lines. These features which protrude from the limb of the     sun are most easily seen in monochromatic light or during a _______________ eclipse of the
    sun. These features are called _______________.

55. Along the boundaries of large cells of flowing chromospheric gas, called supergranules, where
    magnetic fields are intensified, jets of gas called _______________ form. They bob up and
    down in periods of only a few minutes and (through acoustical vibrations--sound waves) may be     responsible for heating the tenuous matter in the sun's _______________ to over one million
    Kelvin (2-6 million F).

56. Through less energetic regions in the solar corona, known as coronal _______________,
    plasma may leave the gravitational field of the sun to be swept outward along with the solar
    magnetic field. This plasma flow is known as the ____________________. Coronal holes
    appear to be regions where an open magnetic field exists, allowing gases to flow outward along     the field lines. This lowers the pressure in the hole regions and therefore _______________ the     temperature. Where normal regions of the corona occur, magnetic fields loop back into the
    corona bottling up this plasma, and preventing its escape. Temperatures and pressures must be

57. _______________ are the most energetic events which occur on the sun. They are associated     with common features in the photosphere known as _______________. They may possibly be     created by magnetic field lines which become disconnected and spray energetic plasma into

58. If this plasma is directed towards earth, radio disruptions and spectacular _______________
    displays can be the result.