Astronomy Exam Review Name ________________________________ Block __

1. Eratosthenes calculated the circumference of the Earth.

a. What is the equation for finding the circumference of the Earth using Eratosthenes’ method?

b. Locations A and B are 1700 kilometers apart on the equator of a planet’s spherical moon. When the sun is directly overhead at point B, a shadow is cast by the pole at Point A at 15 degrees. According to Eratosthenes method, what would the circumference of the moon for this planet be? Show your work!

2. Motions of the solar system. a. How did the geocentric and heliocentric model of the solar system differ?b. The diagram below represents a simple heliocentric model. Which object is represented by letter X?

a) Earth

b) Sun

c) Moon

d) Polaris

c. What is the difference between retrograde and pro-grade motion?

d. According to the diagram below, during which dates is the planet in retrograde motion?

1700km

3. Kepler’s Laws

1. Define Keplers 1st Law

a. What is the equation that you use to find the eccentricity of an ellipse?

E = --------------------------------------

b. An eccentricity of 1 means the shape is a ____________________________. c. An eccentricity of 0 means the shape is a ____________________________.

The diagram below is a constructed ellipse. F1 and F2 are the foci of the ellipse.

e. Please show your work and calculate the eccentricity of the ellipse above.

Kepler’s Second Law of Equal Areasa. Define Kepler’s 2nd Law:

Use the diagram below to answer the questions. The diagram shows a satellite in four different positions as it revolves around a planet. It takes equal time for the satellite to travel between each of the Letters.

1. At which position is the satellite moving the fastest? How do you know?

2. At which position is the satellite moving the slowest? How do you know?

3. At which position is the force of gravity between the planet and the satellite the greatest?

Kepler’s Third Law (p2=a3)a. Define Kepler’s 3rd Law:

b. p2=a3 ;a=p=

c. A comet orbits around the sun at an average distance of 10 A.U.’s. Use Kepler’s 3 rd law (p2=a3) to determine the orbital period of the comet in earth years. SHOW YOUR WORK FOR CREDIT!

4. Angular Size

When two objects look like they are the same size, the size:distance ratio of the two objects must be the same. What is the equation for angular size?

------------------ = ------------------

If the ratio from Ms. McDonnell’s and Ms. Mikesell’s eye to their finger is 1/50, answer the following problems:

1. Ms. Mikesell sees her house in the distance. She knows that her house is 5 meters tall and that from where she is standing it LOOKS as tall as her little finger. How far away is Ms. Mikesell from her house?

2. Ms. McDonnell is on a geologic field trip and needs to figure out how tall a certain rock formation is. She knows that she is 250 meters from the formation when it appears the same size as her little finger. How tall is this rock formation?

5. Newton’s Three Laws of Motion First Law states:

Second Law states:

Third Law states:

What is Inertia?

For each of the examples below, describe which of Newton’s three laws it represents and why.

EXAMPLE EXPLANATION

1. A person’s body is thrown outward as a car rounds a curve on a highway.

Rockets are launched into space using jet propulsion where exhaust accelerates out from the rocket and the rocket accelerates in an opposite direction.

A picture is hanging on a wall and does not move.

Pushing a child on a swing is easier than pushing an adult on the same swing, because the adult has more inertia.

2. A soccer ball accelerates more than a bowling ball when thrown with the same force.

A soccer player kicks a ball with their foot and their toes are left stinging.

A student leaves a pencil on a desk and the pencil stays in the same spot until another student picks it up.

Two students are in a baseball game. The first student hits a ball very hard and it has a greater acceleration than the second student who bunts the ball lightly.

6. Newton’s Universal Law of GravitationKnow the relationship between mass and distance and how it affects gravity. What is the equation for the force of gravity?

Fg= ( )( ) ( )2

For the image below explain how the force of gravity changes in each of the examples.

A.

B.

C.

1. If the mass of object one is doubled, what happens to force of gravity?

2. If the distance between object 1 and object 2 is tripled, what happens to force of gravity?

3. If the mass of object one is doubled and the distance increases 4 times, what happens to the force of gravity?

7. Mass v. WeightMass:________________________________________________________________________Weight:_______________________________________________________________________

How does your weight change based on gravity?

8. Light Year Calculations1. If light travels 9,460,000,000,000 km (9.46 trillion km) in a year, how far will it have traveled in 9.5

lightyears?

2. How fast is the speed of light in km/year?

3. In meters/year?

4. In meters/second?

9. Stellar Parallax1. What is “parallax”?

2. As distance to the star increases, what happens to parallax?________________________

3. As our baseline increases, what happens to parallax? ________________________

4. Explain how parallax helps us determine the distance to the star.

5. Use the formula on the right to solve the following Q’s:

a. Distance = 0.5 parsecsParallax Angle = ?

b. If the distance to the star is 15 parsecs, what parallax angle will we see?

c. If a star has a parallax angle of 0.25 arcseconds, how far away is it?

10. Life Cycle of StarsChoose your answer from the word bank on the right.

1. Which one will have a short lifespan from start to finish? ________________

2. Which one will burn their fuel the most slowly? ________________

3. Which one is most like our sun? ________________

4. Which one has a lot of mass? ________________

5. Which one has the least amount of mass? ________________

6. Which one is the coolest? ________________

7. Which one is the hottest? ________________

8. Describe or draw how the sun produces energy.

9. What will happen to the sun once it runs out of fuel and dies?

10. Clouds of gas and dust where stars are formed are called:

a. Nebula c. Pulsarsb. Red Giants d. Supernovas

11. Newly formed stars are called:a. Protostars c. Red Giantsb. White Dwarfs d. Pulsars

12. Older stars whose core has shrunk and atmosphere has expanded and cooled are called:a. Protostars c. Red Giantsb. White Dwarfs d. Pulsars

13. When a star breaks apart in a tremendous explosion, it is called a/an:a. Protostar c. Pulsarb. White Dwarf d. Supernova

14. What is formed when the core of a dying star is so massive that its gravity doesn’t let anything escape, even light?

a. Black Hole c. Pulsarb. White Dwarf d. Red Giant

Word BankRed Main Sequence StarYellow Main Sequence StarBlue Main Sequence Star

11. Apparent and Absolute magnitudeApparent Magnitude is _____________________________________________________Absolute Magnitude is _____________________________________________________

1. Which of the stars appears brighter from Earth? Which is actually brighter (emitting more energy)?

2. Star A has an apparent magnitude of 1.0 and an absolute magnitude of 1.0. How would the apparent and absolute magnitudes of this star change if the distance between the Earth and this star were decreased?

3. How far away is Star A from earth? ___________________

12. H-R Diagram

What type are most of the stars on this diagram?a. White Dwarfs c. Red giantsb. Supernovas d. Main Sequence

Which star is the brightest?a. Rigel b. Betelguese c. The Sun d. Vega

What property of a star can be determined by its color?a. apparent magnitude b. absolute magnitude c. temperature d. age

Which star is considered a Red Giant?a. Rigel b. Betelguese c. The Sun d. Vega

Apparent magnitude

Absolute magnitude

Star X 5.0 -1.0

Star Y 2.0 3.0

Star A 1.0 1.0

13.Doppler Effecta. Red-Shift means the star is _______________________________________________________________

i. The spectral lines move toward the ______________________part of the EM spectrum.

b. Blue-Shift means the star is________________________________________________________________

i. The spectral lines move toward the ______________________part of the EM spectrum.

c. Draw waves on the diagram below demonstrating what you would hear as the car holds down its horn and drives to the right.

14. Hubble’s Law1. The _______________________ away the galaxy, the _______________________ it is moving away from us.

2. The rate that the galaxies move away from us is ____________________________to their distance from Earth.

3. All galaxies exhibit a _______ ________ which tells us the universe is _______________________.

Study the graphic to the right. Look at the spectral lines of the Laboratory Reference first. Compare the spectral lines of the other objects to these.

1. As the objects get farther away, what happens to the broad line that is at 400nm in the laboratory reference?

2. Which object has spectral lines that are the MOST redshifted?

3. What do we know about the Very Distant Galaxy’s motion? a) Moving toward us quicklyb) Moving towards us slowlyc) Standing still compared to usd) Moving away from us slowlye) Moving away from us quickly

15.Electromagnetic Spectrum1. All Electromagnetic waves are ___________ waves.

2. All electromagnetic waves travel at_______________________________.

3. Wave vocabulary a. Frequency

b. Wavelength

c. Amplitude

4. How are frequency and wavelength related?

5. How do scientists use EM waves to study the composition of stars?

6. What is an emission spectrum? What can scientists learn from looking at a star’s Emission Spectrum?

1. What type of waves have the highest frequency? ______________________

2. What type of waves have the shortest wavelength? ______________________

3. What type of waves are harmful (more than 1)? ______________________

4. What type of waves have the most energy? ______________________

5. What type of waves, if any, travel the fastest? ______________________

6. Which COLOR would be produced by the hottest main sequence stars? ______________________