Free Essay

The Sun Our Star

In: Other Topics

Submitted By janelatobi
Words 1628
Pages 7
CHAPTER 8—THE SUN-OUR STAR

Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.

____ 1. Granulation is caused by
|a. |sunspots. |
|b. |rising gas below the photosphere. |
|c. |shock waves in the corona. |
|d. |the solar wind flowing away from the corona. |
|e. |the heating in the chromosphere. |

____ 2. In some regions of the corona, the magnetic field does not loop back to the sun, and the gas escapes unimpeded. These regions are called _______________ and are believed to be the source of the solar wind.
|a. |prominences |
|b. |flares |
|c. |granules |
|d. |auroras |
|e. |coronal holes |

____ 3. Most of the light we see coming from the sun originates in the
|a. |chromosphere. |
|b. |photosphere. |
|c. |corona. |
|d. |sunspots. |
|e. |magnetic field. |

____ 4. A filtergram is a photograph of the sun's surface made
|a. |in a band of wavelengths in the infrared. |
|b. |in a band of wavelengths in the ultraviolet. |
|c. |using the Zeeman effect. |
|d. |with only those photons emitted in a specific spectral line. |
|e. |none of the above |

____ 5. Modern astronomers suspect the corona is heated by
|a. |shock waves rising from below the photosphere. |
|b. |the solar wind. |
|c. |the solar magnetic field. |
|d. |all of these |
|e. |none of these |

____ 6. Sunspots are known to be magnetic phenomena because
|a. |Doppler shifts in spectral lines are observed. |
|b. |the Zeeman effect is observed in sunspots. |
|c. |collisional broadening is observed in spectral lines. |
|d. |infrared observations indicate that the sunspots are cooler than their surroundings. |
|e. |observations during eclipses reveal a very extensive photosphere. |

____ 7. The solar constant is a measure of
|a. |the amount of solar energy reaching the earth. |
|b. |the length of the sunspot cycle. |
|c. |the period of rotation of the sun's equator. |
|d. |the average number of sunspots seen during the Maunder minimum. |
|e. |the sun's mass. |

____ 8. The sunspot cycle affects

|I. |the latitude at which sunspots are visible at a given time. |
|II. |the number of sunspots that are visible at a given time. |
|III. |the rotation rate of the sun's equator at a given time. |
|IV. |the magnetic polarity of the sunspots at a given time. |

|a. |I & II |
|b. |I & IV |
|c. |II & III |
|d. |I, II & III |
|e. |I, II, & IV |

____ 9. The sun's magnetic field is evident in the looped shapes of
|a. |solar flares. |
|b. |sunspots. |
|c. |the corona. |
|d. |granules. |
|e. |solar prominences. |

____ 10. Sunspots are dark because
|a. |regions of the photosphere are obscured by material in the chromosphere. |
|b. |shock waves move through the photosphere. |
|c. |the sun rotates differentially. |
|d. |the strong magnetic field inhibits the currents of hot gas rising from below. |
|e. |they radiate their energy into space faster than the rest of the photosphere. |

____ 11. The photosphere is very thin because
|a. |the temperature of the photosphere increases rapidly from its base to its outer edge. |
|b. |the gas bubbles that form the granulation pattern cannot travel very far. |
|c. |the magnetic field compresses the photosphere. |
|d. |the H- ion is a very good absorber of photons and causes the gas of the photosphere to be opaque. |
|e. |the sun rotates differentially. |

____ 12. The diagram below shows a plot of the temperature of the sun as a function of distance above the bottom of the photosphere. At what distance above the bottom of the photosphere does the temperature of the sun change the most rapidly with distance?

[pic]

|a. |1,000 km |
|b. |2,300 km |
|c. |2,500 km to 4,000 km |
|d. |500 km |
|e. |a and c |

____ 13. The centers of granules
|a. |are hot material rising to the photosphere from below. |
|b. |are cool material falling from the photosphere to the regions below. |
|c. |are fainter and hotter than their surroundings. |
|d. |are brighter and cooler than their surroundings. |
|e. |show strong Zeeman effects. |

____ 14. What evidence supports the contention that other sun-like stars also show a spot cycle much like our sun's sunspot cycle?
|a. |the variation in the rotation rates of sun-like stars |
|b. |the variation in the nuclear reaction rates in sun-like stars |
|c. |the variation in the strength of the H and K emissions in the spectra of sun-like stars |
|d. |the variation in the parallax of sun-like stars |
|e. |the variation in the color of sun-like stars |

____ 15. Spicules
|a. |are found in the photosphere. |
|b. |are magnetic disturbances that push large loops of material off the solar surface. |
|c. |are responsible for twisting the solar magnetic field and causing the sunspot cycle. |
|d. |appear in the corona near the north and south poles of the sun during a total solar eclipse. |
|e. |are visible in filtergrams of the solar chromosphere. |

____ 16. The most recent sunspot maximum occurred in 2001, when is the next sunspot maximum expected if the solar cycle continues?
|a. |1990 |
|b. |2006 |
|c. |2012 |
|d. |2023 |
|e. |The last cycle started a Maunder minimum, and the next maximum can not be predicted. |

____ 17. The variation in the strength of the calcium H and K emission from sun-like stars implies that these stars
|a. |probably have very extended coronae. |
|b. |probably have a magnetic cycle similar to the sun's. |
|c. |do not rotate differentially. |
|d. |may have planets that orbit them. |
|e. |probably have supergranules and spicules |

____ 18. A _______________ is believed to occur when energy, stored in a twist in the solar magnetic field above a sunspot, is suddenly released.
|a. |solar flare |
|b. |supergranule |
|c. |spicule |
|d. |coronal hole |
|e. |none of the above |

____ 19. Sunspots
|a. |are hotter than their surroundings. |
|b. |are regions where material is rising from below the photosphere. |
|c. |show the Zeeman effect indicating the presence of strong magnetic fields. |
|d. |produce spicules. |
|e. |are generally found near the poles of the sun during sunspot maximum. |

____ 20. The _______________ is (are) the hot gases that are the moving extension of the sun's corona.
|a. |spicules |
|b. |prominences |
|c. |flares |
|d. |supergranules |
|e. |solar wind |

____ 21. The corona of the sun can be observed
|a. |during a lunar eclipse. |
|b. |with a coronagraph. |
|c. |using filtergrams. |
|d. |a and b above |
|e. |with none of the above |

____ 22. _______________ occurs because photons we receive from the edge of the solar disk are emitted further from the base of the photosphere than the photons we receive from the center of the solar disk.
|a. |The Zeeman effect |
|b. |Sunspots |
|c. |Solar flares |
|d. |Solar prominences |
|e. |Limb darkening |

____ 23. The United States consumes 2.5[pic]1019 J of energy each year. A typical solar flare releases 5.0[pic]1024 J of energy. How many years could we run the United States on the energy released by this solar flare if all of the released energy could be used?
|a. |5[pic]10-6 years |
|b. |200,000 years |
|c. |1.25[pic]1044 years |
|d. |about 12 years |
|e. |500 years |

____ 24. If a sunspot has a temperature of 4,500 K and the surrounding solar surface has a temperature of 5,800 K, how many times brighter is the surface compared to the sunspot?
|a. |0.28 |
|b. |0.36 |
|c. |2.8 |
|d. |3.6 |
|e. |36 |

____ 25. The intensity of a sunspot is found to be 3 times smaller than the intensity emitted by the solar surface. What is the approximate temperature of this sunspot if the temperature of the solar surface is 5,800 K?
|a. |4,400 K |
|b. |470,000 K |
|c. |1,900 K |
|d. |7,600 K |
|e. |1,400 K |

True/False
Indicate whether the sentence or statement is true or false.

____ 26. Most of the visible light from the sun originates in the photosphere.

____ 27. Granulation is caused by rising currents of hot gas below the photosphere.

____ 28. The flash spectrum shows that temperature falls with increasing height in the chromosphere.

____ 29. A filtergram is used to study layers below the photosphere.

____ 30. The corona is heated by the solar magnetic field.

____ 31. The Zeeman effect shows that sunspots contain magnetic fields.

____ 32. Sunspots are hotter than the photosphere.

____ 33. An older theory suggested that the corona was heated by shock waves from the convection zone.

____ 34. Solar flares have no known effect on the Earth.

____ 35. Solar prominences have twisted and looped shapes because of the solar magnetic field.
CHAPTER 8
Answer Section

MULTIPLE CHOICE

1. ANS: B

2. ANS: E

3. ANS: B

4. ANS: D

5. ANS: C

6. ANS: B

7. ANS: A

8. ANS: E

9. ANS: E

10. ANS: D

11. ANS: D

12. ANS: B

13. ANS: A

14. ANS: C

15. ANS: E

16. ANS: C

17. ANS: B

18. ANS: A

19. ANS: C

20. ANS: E

21. ANS: B

22. ANS: E

23. ANS: B
Note to the Instructor: This question requires the use of mathematics and is similar to the problems at the end of the chapter.

24. ANS: C
Note to the Instructor: This question requires the use of mathematics and is similar to the problems at the end of the chapter.

25. ANS: A
Note to the Instructor: This question requires the use of mathematics and is similar to the problems at the end of the chapter.

TRUE/FALSE

26. ANS: T

27. ANS: T

28. ANS: F

29. ANS: F

30. ANS: T

31. ANS: T

32. ANS: F

33. ANS: T

34. ANS: F

35. ANS: T

Similar Documents

Free Essay

Stars

...Famous Stars in our Galaxy There are about 300 billion different stars in our galaxy. All of which contain different history, characteristics and general information. They each contain their own story of how they came about. Many of these stars are a part of a certain constellation and have been around for billions of years. Polaris is one the best known stars. (“How Do Stars Form,” n.d.) This star is known by many names like the North or Pole Star. Polaris has not always been the North Star and will not always remain the North Star. As centuries change the North Star will also do so. “A famous star called Thuban, in the constellation Draco the Dragon, was the North Star when the Egyptians built the pyramids.” (earthsky) Polaris will remain as the North Star for many more centuries to come. There was a time where people depended on their lives on this star to guide them. Fortunately, they used the North Star and the Big Dipper without getting lost. “. When slavery existed in the United States, slaves counted on the Big Dipper (which they called the Drinking Gourd) to show them the North Star, lighting their way to the free states and Canada.” (earthsky) Polaris is not hard to miss in the sky; it is the 50th brightest star and does not disappear. The reason this star will not disappear is due to the fact that the Earth’s axis is aligned pointing towards Polaris in the same direction North faces but will eventually shift over time. In comparison to the sun, this star is 10,000...

Words: 2479 - Pages: 10

Premium Essay

What Makes A Low Mass Star

...low mass stars have huge influences on our universe, but do you know what influence they have. Stars emit energy at 10 million degrees celsius by the process of nuclear fusion. nuclear fusion can releases a lot of energy. Low mass stars are formed in a nebula of swirling gases. Low mass star’s life cycle forms from a cloud of hydrogen gas to a dense ball if heated carbon which will burn out over a long period of time which can leave elements behind that can be used to form planets.After this process a white dwarf can form after millions of years which will eventually cool after another few million years and become a black dwarf. The sun is also a low mass star. But what keeps our sun going as a low mass star and will it ever explode....

Words: 505 - Pages: 3

Free Essay

My Life

...Milky Way B) you, Earth, solar system, Milky Way, Local Supercluster, Local Group C) you, Earth, solar system, Local Group, Milky Way, Local Supercluster D) you, Earth, Local Group, Local Supercluster, solar system, Milky Way E) you, Earth, solar system, Milky Way, Local Group, Local Supercluster Answer: E 3) About where is our solar system located within the Milky Way Galaxy? A) at the center of the galaxy B) about 10 percent of the way from the center of the galaxy to the outskirts of the galactic disk C) about two-thirds of the way from the center of the galaxy to the outskirts of the galactic disk D) near the far outskirts of the galactic disk E) in the halo of the galaxy above the galactic disk Answer: C 4) Roughly how many stars are in the Milky Way Galaxy? A) 1 billion B) 100 billion C) 10 billion D) 100 million E) 100 trillion Answer: B 5) Modern telescopes are capable of seeing bright galaxies up to about A) 1 million light-years away. B) 10 million light-years away. C) 1 billion light-years away. D) 10 billion light-years away. E) 1 trillion light-years away. Answer: D 6) Suppose we imagine the Sun to be about the size of a grapefruit. How big an area would the orbits of the eight planets of the solar system cover? A) the size of a typical dorm room B) the size of a typical campus building...

Words: 6866 - Pages: 28

Premium Essay

Week 1 Sci 151

... 1. Our place in the universe a. The modern view of the universe 1) What is our Sun and what is its role in the solar system? a. The Sun is a fairly ordinary but large star. b. The Sun is the focal point of our solar system, because all of the planets orbit the Sun. 2) What is our Milky Way galaxy and the sun’s position in it? a. The Milky Way galaxy is where our solar system is located in the universe. b. The Milky Way galaxy is home to over 100 billion stars and the Sun is one of those stars. 3) What is the Big Bang and what does it say about the age of the universe? a. The Big Bang is when the universe began. b. The Big Bang is thought to have happened about 14 billion years ago. 4) What is meant by the phase “looking out in the universe is looking back in time?” a. When viewing the universe we see a vast amount of stars. b. The light from stars must travel great distances to reach us, and these distances take years. c. So when we see a star we are seeing the star as it was when the light first started traveling. b. Where are we in the universe? 1) What is Earth’s place in the solar system? a. The Earth is our home. b. The Earth is the only planet known to sustain human life. 2) How close are the nearest stars to the Sun as compared to the distance between the Sun and the Earth? 3) How large is our Milky Way galaxy? a. The Milky Way galaxy is home to our solar system. b. The Milky Way galaxy has a 100,000 light-year diameter. 4) How many stars are estimated...

Words: 1262 - Pages: 6

Premium Essay

Weather Astronomy In Yann Martel's Life Of Pi

...While reading Yann Martels «life of Pi» book Pi always talked about stars and moon he always described them. Sky is very mystery and interesting, it is always helped to people know the way, know the weather and many other things. Stars. We always see them at night. They draw our attention to the special, mesmerizing glow. Our ancestors believed that they can influence our destiny and our future. I think they can’t say about our fate but they can say us about weather  and they can help us to find our way if we are lost.  For a long time one of the main purposes of astronomy has navigation - star guided the captains of ships in the high seas and the conductors of caravans in the desert, for many centuries helped the stars do not go astray travelers. Navigation with the stars: The most common way to navigate by stars...

Words: 1429 - Pages: 6

Premium Essay

Basics of Astronomy Outline

... Our place in the universe A. The modern view of the universe 1. The Sun is a star in our solar system that generates heat and light to our planet, Earth through nuclear fusion. 2. Our Milky Way galaxy is an island of stars in space with hundreds of billions of stars like our Sun. 3. The Big Bang is a theory of when the universe started expanding about 14 billion years ago. 4. The phase “looking out in the universe is looking back in time,” refers to the light from other stars we see at night happened in 1913 because light takes time to travel through space. B. Where are we in the universe? 1. Earth’s place in the solar system is the third planet nearest to the Sun, a star. It is very small but the only dense planet with life forms. 2. The nearest stars to the Sun and compare the distance between the Sun and Earth a. The nearest star system is Alpha Centauri that is 4.4 light-years away. b. The distance between the Earth, and the Sun is 92,600,000 miles; it takes eight minutes for light from the Sun to reach Earth. 3. The Milky Way galaxy is about one hundred thousand light-years in diameter. 4. It is estimated that one hundred billion stars are in our galaxy. 5. The Earth is only four and one-half billion years of age in comparison to the universe is 14 billion. C. Motion in the universe 1. Earth orbits the Sun at 66,000 miles per hour that is equal to 107,000 kilometers per hour, which is one hundred times faster than a speeding bullet. 2. Our Sun is moving...

Words: 978 - Pages: 4

Free Essay

The Paper

...completed outline: 1. Our place in the universe a. The modern view of the universe 1) What is our Sun and what is its role in the solar system? a) Our sun is a hot ball of glowing gases that is at the heart of our solar system. b) Our suns role is to give out energy and heat. This energy and heat allows for there to be life on earth. However, even though our sun is unique and life giving there are billions of stars that are just like it in the Milky Way galaxy. (Solar System Exploration, 2012) 2) What is our Milky Way galaxy and the sun’s position in it? a) The Milky Way galaxy is a spiral galaxy that has arms that extend out from the center like a pinwheel. Our galaxy is one of about 100 billion visible universes. (Solar System Exploration, 2012) b) The sun’s posistion in the galaxy is in the Orions arm of the Mily Way. However, because of how our planets are set up in our system there is life on Earth. The Sun has an almost circular orbit. The sun is just the right distance from the center of our galaxy to promote life. The planets and our sun are just the right distance apart for one of our planets, Earth, to have higher intelegance life on it. 3) What is the Big Bang and what does it say about the age of the universe? a) Scientist says that the Big Bang is what created our universe. Edwin Hubble was the first, in 1929, to discover that the Universe was expanding an great speeds. Now Hubble discovered that planets and galaxies that were outside our own are moving away...

Words: 3291 - Pages: 14

Premium Essay

Te Earth an Space

...The earth and space Did you ever wonder what was outside our atmosphere? Well I’m going to tell you the many things that are in our solar system and maybe beyond it. We will start with our moon, its shape resembles an egg, and has been around for 4.5 billion years. Neil Armstrong was the first person to set foot on the moon. The year was 1969 and the mission was called Apollo 11. After all the excitement from their landing Armstrong made a statement when he stepped out of his aircraft. “That’s one small step for man, one giant leap for mankind.” The moon has little to no atmosphere, and has a weak gravitation. The surface of the moon has not changed in 3 billion years, so a foot print on the moon from a million years ago would still be there today. Because the moon has little to no atmosphere there isn’t any water to create erosion and there is no wind. The temperatures of the moon vary from day to night. During the day the temperature is approximately +300°F and night time is -270°F. The temperature is this way due to the fact there is no atmosphere to protect against the sun and keep it warm at night (MoonPhases.Info, 2010-2011). The coolest cosmic entity in the sky is the moon. At night when the moon is out, it’s the first thing that lights up the night sky. It takes 27.3 days for the moon to turn on its axis and to orbit the earth. Due to this it makes the moons phases and orbit a mystery (Charles Q. Choi, 2013). Below is a photo of the moon. Some...

Words: 1817 - Pages: 8

Free Essay

Title

...) Our subscribers' grade-level estimate for this page: 4th - 5th | Table of Contents | Enchanted Learning All About Astronomy | Site Index | Our Solar System | Stars | Glossary | Printables, Worksheets, and Activities | The Sun | The Planets | The Moon | Asteroids | Kuiper Belt | Comets | Meteors | | Astronomers | | The Stars | Lifecycle | Nuclear Fusion | Brightest Stars | Galaxies | Other Solar Systems | Constellations | Why Stars Twinkle | Birth | Death | Star Types | Closest Stars | Nebulae | Major Stars | The Zodiac | Activities, Links | STARS Each star in the sky is an enormous glowing ball of gas. Our sun is a medium-sized star.  Stars can live for billions of years. A star is born when an enormous cloud of hydrogen gas collapses until it is hot enough to burn nuclear fuel (producing tremendous amounts heat and radiation). As the nuclear fuel runs out (in about 5 billion years), the star expands and the core contracts, becoming a giant star which eventually explodes and turns into a dim, cool object (a black dwarf, neutron star, or black hole, depending on its initial mass). The largest stars have the shortest life span (still billions of years); more massive stars burn hotter and faster than their smaller counterparts (like the Sun). The composition of stars is studied using spectroscopy in which their visible light (the spectrum) is studied.  GROUPS OF STARS  In the universe, most stars occur in groups of at least two stars. Two...

Words: 970 - Pages: 4

Premium Essay

Half Life Research Paper

...Section One, Part One Molecular clouds(Very large clouds of gas and dust tens of times larger than our solar system) run amuck in space. Inside, larger particles of dust attract smaller ones, because they have a stronger gravitational pull. These larger particles continued to gain mass. As one solid mass, now known as a protostar, is around 10 to 20 Kelvins. To become a star, the protostar must reach 15,000,000°. Until the mass reaches 15,000,000°, it will remain a protostar. Section One, Part Two Most of the stars life is controlled by nuclear fusion. When a star reaches the perfect temperature of 15,000,000° Kelvin, it forms hydrogen. The star continues to heat up. Hydrogen molecules bash and form together to create helium with an atomic...

Words: 2088 - Pages: 9

Premium Essay

Lecture Notes

...If nuclear fusion of hydrogen in the core of the Sun were to stop now, what would we see on the surface of the Sun tomorrow? Why? Will we be able to tell that hydrogen burning in the core has stopped? How? (20pt) (Hint: What particles that are generated by the fusion of hydrogen can escape from the interior of the Sun immediately?) You won’t be able to see any changes on the surface of the Sun…probably you won’t see anything from helioseismology data either. This is because photons generated in the core of the Sun takes about one million years to get to the surface. This means that the thermal energy generated in the last minute of the fusion will last for about a million years, and the Sun will just very slowly contract. So, we will not see changes on the surface until a million years later. However, we should be able to tell that the hydrogen fusion in the core has stopped by observing the solar neutrinos. The neutrinos do not interact with the solar plasma, and can escape the Sun and reach Earth in about 8 minutes. So, we would find that the neutrino flux is decreased. 2. Chapter 11, Review Question 7. What is the defining characteristic of a main-sequence star? How is surface temperature related to luminosity for main-sequence stars? (20pt) 3. Is this statement sensible? Why, or why not? (20pt) If the Sun had been born as a high-mass star some 4.6 billion years ago, rather than as a low mass star, the planet Jupiter would probably have Earth-like...

Words: 699 - Pages: 3

Premium Essay

The Sun

...“SUN” The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields. The Sun is a G-type main-sequence star comprising about 99.86% of the total mass of the Solar System. The Sun consists of plasma and is not solid. It rotates faster at its equator than at its poles. This behavior is known as differential rotation, and is caused by convection in the Sun and the movement of mass. The Sun is a Population I or heavy element-rich star.  The formation of the Sun may have been triggered by shockwaves from one or more supernovas. The Sun does not have a definite boundary as rocky planets do. Through most of the Sun's life, energy is produced by nuclear fusion through a series of steps called the proton–proton chain. This process converts hydrogen into helium. The Sun is a magnetically active star that supports a strong, changing magnetic field that varies year to year and reverses direction about every eleven years around solar maximum. The Sun's magnetic field leads to many effects that are called solar activity which carries material through the Solar System. Solar activity changes the structure of Earth's outer atmosphere. All matter in the Sun is in the form of gas and plasma because of its high temperatures. This makes it possible for the Sun to rotate faster at its equator than it does at higher latitudes. The Sun was formed about 4.57 billion years ago from the collapse...

Words: 894 - Pages: 4

Free Essay

The Science of Stars

...The Science of Stars Rochell Clark August 13, 2012 SCI 151 Robert Austin Stars are the majority and most widely acknowledged astronomical components that symbolize the most essential development of blocks of galaxies. The age, disbursement, and framework of the night sky in a galaxy maintain a record of the heritage, characteristics, and evolvement of the galaxy. More important, stars are integral to the fabrication and allocation of heavy elements. Notably corresponding to carbon, nitrogen, and oxygen, their functionality is intimately associated with the capabilities of the planetary models, which in turn associate about them. Subsequently, the analysis of the conception, longevity, and perishing of stars is dominant to the subject of astronomy. Astronomers depend on electromagnetic emissions observed by unique variations of telescopes to calculate the position, structure, conditions, activity, and magnetism of celestial objects. The conduct of the majority of stars indicates they generate a certain measure of energy at each wavelength however additionally carry a pinnacle wavelength and range in which they discharge a significant amount of their remaining stamina. Electromagnetic radiation is transmitted by means of waves at the speed of light (299 792 km/sec) through space. Electromagnetic waves consist of marginal frequency radio waves with the aid of infrared energy and observable luminosity to ultraviolet radiation x-rays as well as high frequency gamma radiation...

Words: 1314 - Pages: 6

Free Essay

Physics

...Chapter 10 : The Sun THE SUNS ATMOSPHERE * the sun is so hot that it neither has a liquid or solid matter anywhere inside of it * moving down into the sun there is denser and hotter masses Photosphere (“sphere of light”) * The photosphere is the innermost of layer of the three layers that comprise the suns atmosphere * A gas layer of the sun that has the most visible light * It is about 400 km thick * Density of the photosphere is low by the earth standards about 0.01% as the air we breathe * Photosphere has a blackbody spectrum that corresponds to an average temp of 5800K * The photosphere appears darkest toward the edge or limb of the solar disk , a phenomenon called limb darkening, * This occurs b/c we see regions of different temp at different depths of the photosphere Granules * lightly colored convection features about 100 km in diameter seen constantly in the solar photosphere * time lapse photography shows that granules form, disappear then reform in cylces that last several minutes Chromosphere (“sphere of color”) * is a dim layer of less dense stellar gas that is above the photosphere * It is the layer we normally see * Astronomers can also study the chromosphere through filters that pass light with specific wavelengths strongly emitted by it – but not by the photosphere – or through telescope sensitive to nonvisble wavelengths that the chromosphere emits intensely Spicules - Are...

Words: 7381 - Pages: 30

Premium Essay

Structure of the Universe

...Chapter 1: Our Place in the Universe 1.1 Our Modern View of the Universe * Geocentric universe: Earth-centered * Solar system: the Sun and all the objects that orbits it * Our solar system formed 4.5 billion years ago * Galaxy: great island of stars in space, having from a few hundred million to a trillion or more stars * Milky Way Galaxy contains more than 100 billion stars; our Milky Way is in the Local Group * Galaxy cluster: collection of galaxies bound together by gravity. Small collections (up to a few dozen) are generally called groups, while larger collections are called clusters * Supercluster: gigantic region of space where many individual galaxies and many groups and clusters of galaxies are packed more closely together than elsewhere in the universe * Universe (cosmos): the sum total of all mater and energy * Observable Universe: the portion of the entire universe that can be seen from Earth * Universe is expanding, Big Bang occurred 14 billion years ago * Planet: moderately sized object that orbits a star and shines primarily by reflecting light from its star; an object is a planet if it (1) orbits a star, (2) is large enough for its own gravity to make it round, and (3) has cleared most other objects from its orbital path * Dwarf planet: object that meets the first two criteria but not the third, like Pluto * Moon (or satellite): an object that orbits a planet * Asteroid: a relatively small and rocky...

Words: 6164 - Pages: 25