ASTRONOMY FINAL EXAM REVIEW

Intro Unit

  1. How many stars are in our solar system? How many stars are in the Milky Way Galaxy?

Oneabout 200 billion

  1. If a star is 8.5 light years away, what does that mean about the light I see tonight?

The light left the star 8.5 years ago

  1. The speed of light is approximately 300,000 km/s
  2. The average distance from the Earth to the sun. One Astronomical Unit, 150 million km
  3. The spiral galaxy that contains the Earth and sun. Milky Way
  4. The sun, planets, moons, asteroids, and comets are the major parts of this.Solar System
  5. A unit of distance determined by how far light travels in a set period of time. Light Year
  6. A luminous globe of gas held together by its own gravity and supported by the internal pressure generated by nuclear fusion. Star

History of Astronomy

9. From the “History of Astronomy” unit, name the early astronomers that supported a geocentric model of

the universe, and those that accepted a heliocentric model of the universe:

Geocentric- Aristotle, Ptolemy,

Heliocentric- Copernicus, Kepler, Galileo, Newton

10. What is the difference between mass and weight?

Mass- how much matter; Weight- force of gravity pulling on that matter

Our Solar System

  1. Where are most of the moons in our solar system located? Outer Planets
  1. Planets, asteroids, and comets all orbit the Sun
  2. What is the main difference between planets and dwarf planets?

Planets have cleared their orbital paths, Dwarf planets have “neighbors”

Earth’s Motions and Seasons

  1. What causes day and night?Earth’s rotation
  1. The closest point of a planet’s orbit around the sun is called Perihelion
  1. What happens to the length of days in the Northern Hemisphere between June 21 and September 21?

June 21 is summer solstice (longest day) so as we head into fall, days get shorter

  1. Which direction does the earth rotate on its axis?Counter-clockwise
  1. The two forces that keep celestial bodies in orbit are inertiaand gravity

For # 19-21, identify if the observation is caused by Earth’s ROTATION or REVOLUTION:

  1. The sun rises in the morning. Rotation
  2. The constellations visible in the southern sky in February are different than those visible in August.Revolution
  3. The constellation Auriga is right overhead at 8 pm and sets below the horizon near dawn. Rotation

The Moon

  1. How does the rotational period of the moon compare to the time it takes to orbit the Earth?

They are the same (tidally locked moon)

  1. During which phase of the moon can a total lunar eclipse occur? Full
  1. What is the difference between the “far side” of the moon and the “dark side” of the moon?There is no far side because the moon rotates and every part gets day and night, so no dark side. but because time of rotation = revolution time, we always see the same side of the moon and never see the “far side”

  1. What causes the appearance of the moon’s phases as seen from Earth? As the moon orbits Earth, the angle formed between the moon, earth, and sun changes and we can see different amounts of the lit half of the moon.
  1. Which of these factors does nothave an impact on crater size? Circle one:

phase of the moon upon impact

  1. Describe or draw the locations of the Earth, Sun, and Moon during a lunar eclipse:

Sun  Earth  Moon

  1. Describe or draw the locations of the Earth, Sun, and Moon during a solar eclipse:

Sun  Moon Earth

The Night Sky and the Celestial Sphere

  1. Star A has an apparent visual magnitude of 3.3 and star B has an apparent magnitude of 5.3. Which star appears brighter? How do you know?

Star A, because smaller numbers = brighter appearance

  1. The Zenithis the point on the celestial sphere directly above the observer.
  1. What is the difference between the apparent visual magnitude and the luminosityof a star?

Apparent visual magnitude is how bright it LOOKS from Earth, while luminosity is how bright it

actually IS (how much light it is giving off)

  1. If you watched the night sky for several hours, what would you observe about the movement of stars in the south near the celestial equator? What would you observe about the movement of Polaris? Why?

Southern stars would appear to move from east to west due to earth’s rotation, but Polaris

would stay still because it is aligned with Earth’s axis of rotation.

  1. What is the declination of the celestial equator? 0o
  1. What is the modern definition of constellations?

88 pieces of sky with well-defined borders

  1. The brightness of a star as seen by human eyes on Earth. Apparent visual magnitude
  2. A constellation so close to one of the celestial poles that it never sets or rises. Circumpolar Constellations
  3. The circular visual boundary between the sky and Earth. Horizon
  4. An imaginary sphere surrounding the Earth to which the celestial objects seem to be attached:

Celestial sphere

  1. One of the ancient stellar patterns identified by name, usually originating from Greek mythology, or one of the 88 regions of the sky as defined by the IAU. Constellation
  1. The path the sun follows along the sky over the course of the year, also marks the Earth’s orbit : ecliptic
  2. A recognizable pattern of stars such as the Big Dipper or the Winter Triangle, may cross the borders of a

constellation. Asterism

Telescopes and The Electromagnetic Spectrum

  1. The DOPPLEReffect indicates if an object is moving toward or away from an observer.
  1. Name the different types of light on the electromagnetic spectrum, from least energetic to most energetic:

Radio, Microwave, Infrared, Visible (ROYGBIV), Ultraviolet, X-rays, Gamma Rays

  1. Hot objects will emit light at Shorterwavelengths, while cool objects will emit light at longerwavelengths.
  2. Light can behave as both a particleand as a wave.
  1. A photonis a quantum (particle) of electromagnetic radiation that carries energy.
  1. Light is a form of energy.
  1. Can we see all wavelengths of light? NOPE
  1. The amount of energy a photon carries depends on its wavelengthand frequency
  1. Which wavelengths are shorter than visible light? Ultraviolet, X-rays and Gamma rays
  1. Which type of electromagnetic radiation has the lowest energy? Radio waves
  1. Waves with higher energy tend to haveShorterwavelengths and higherfrequencies
  1. Which of the properties of a telescope is LEAST important? Magnification
  1. The diagram on the right shows a Cassegrain Reflectingtelescope.

The Sun and Other Stars

  1. Where were atoms of elements such as helium and carbon formed? Cores of stars
  1. What types of stars end their lives as supernovae? High mass stars
  1. The sun is composedof mostly which two elements? Hydrogen and helium
  1. Stars produce light through nuclear fusion. Fusion converts massinto energy
  1. What information is plotted on an H-R Diagram? Temperature and luminosity
  1. Astronomers can learn about the temperatureof a star by studying its color and spectrum.