1. The Solar System Lessons 1 Sample Questions
Midterm Review
The Solar System
Lessons 1
Sample Questions

2. On the summer solstice the Earth’s southern hemisphere is tilted toward the Sun.
The seasons are caused by the Earth’s tilt and its orbital motion.
During summer solstice the northern
hemisphere is tilted toward the Sun.
At this time it is summer in the northern hemisphere where the light is more intense and winter in the southern hemisphere where the light is less intense.
Earth's Motion

3. On the summer solstice the Sun is farthest north of the celestial equator halting its northward movement.
The seasons are caused by the Earths
tilt and its orbital motion.
On the summer solstice the noon time
Sun in the northern hemisphere will reach it’s highest (most northern) point in the sky. It will be north of the celestial equator by 23.5 degrees. This is the longest day of the year.
On the winter solstice the noontime Sun in the northern hemisphere will reach its lowest (most southern) point in the sky. This is the shortest day of the year.
Earth's Motion

4. In which direction does the Sun move along the ecliptic?
Eastward
If you could see the stars during the day, the Sun would appear to move eastward along the zodiac through out the year.
Earth's Motion

5. Precession of the rotation axis of Earth is caused by the Earth’s magnetic field.
The Earth’s rotation axis is processing or moving in a circle. It takes 26,000 years for the axis to make one complete trip.
This is caused by the force of the Sun and Moon’s gravity on Earth’s equatorial bulge.
Earth's Motion

6. You live in Killeen, TX at a latitude of 31° N
You live in Killeen, TX at a latitude of 31° N. What is the angle between the northern horizon and the North Celestial Pole?
31°
The Earth’s rotation axis points toward the North Celestial Pole (very near Polaris) . For this reason an observer in the northern hemisphere will see Polaris above the northern horizon at an angle equal to their latitude.
Latitude Calculations

7. You live at a latitude of 20° S
You live at a latitude of 20° S. What is the angle between the southern horizon and the South Celestial Pole?
20°
In the southern hemisphere, observers can not see Polaris.
The South Celestial
Pole is above the southern horizon by an angle equal to the observer’s latitude.
Latitude Calculations

8. You live at a latitude of 54° N
You live at a latitude of 54° N. What is the angle between the southern horizon and the Sun at noon on the vernal equinox?
36°
At equinox the Sun will rise to the Celestial Equator. In the northern hemisphere, the celestial equator is above the southern horizon at an angle complementary to the observer’s latitude.
In this situation, the Sun will be 90° - 54°= 36°above the southern horizon.
Latitude Calculations

9. You live at a latitude of 54° N
You live at a latitude of 54° N. What is the angle between the southern horizon and the Sun at noon on the summer solstice?
59.5°
On the summer solstice the Sun will be 23.5° above the equator. This means that it will be 23.5°above the Celestial Equator. So first locate the Celestial Equator and then add 23.5°
90° - 54°= 36°
36° °= 59.5°
Latitude Calculations

10. You live at a latitude of 54° N
You live at a latitude of 54° N. What is the angle between the southern horizon and the Sun at noon on the winter solstice?
12.5°
On the winter solstice the Sun will be 23.5° below the equator. This means that it will be 23.5°below the Celestial Equator. So first locate the Celestial Equator and then subtract 23.5°
90° - 54°= 36°
36° °= 12.5°
Latitude Calculations

11. A lunar eclipse occurs when the Earth passes between the Earth’s moon and the Sun.
Lunar eclipses only occur during full moon and when the moon is on or near the ecliptic. (Earth’s orbital plane)
Finally, lunar eclipses only occur when the Earth passes between the Moon and the Sun, so that Earth’s shadow falls on the Moon.
Eclipses

12. A total lunar eclipse will occur when the Moon is inside the Earth’s penumbra.
Total lunar eclipses occur:
During full moon
When the moon is on or near the ecliptic. (Earth’s orbital plane)
When the Moon is in Earth’s umbra
Lunar eclipses are visible by all observers on Earth who can see the Moon at that time.
During totality the Moon will glow a coppery red since bluer light is scattered by the Earth’s atmosphere.
Eclipses

13. A solar or lunar eclipse will occur when the Sun is near the line of nodes, and the moon is new or full.
Eclipse seasons occur when the Sun crosses the Moon’s line of nodes. If the Moon is new at that time a solar eclipse may occur. If the Moon is full a lunar eclipse may occur.
The line of nodes is a line drawn between the two points where the Moon’s orbit intersect the Earth’s orbital plane. Each of these points is called a node of the moon’s orbit.
Eclipses

14. A solar eclipse occurs when the Sun passes between the Earth and its moon.
A solar eclipse occurs when the Earth’s moon passes between the Earth and the Sun.
During a total solar eclipse the Moon’s umbra blocks out the Sun’s photosphere allowing observers to study the corona.
Partial solar eclipses result from observers being in the Moon’s penumbra.
Annular solar eclipses result when the Moon’s umbra does not reach Earth.
Eclipses

15. The path of totality can be seen by all observers on Earth who can see the Sun at that time.
The path of totality refers to solar not lunar eclipses since all observers on Earth can see lunar eclipses, if they can see the moon at the time of the eclipse.
Total solar eclipses however are only visible along a well defined “path of totality” which is the result of the Moon’s umbra sweeping across the Earth’s surface.
Eclipses

16. The phases of the moon are caused by its spherical shape and orbital motion around the Sun.
The phases of the moon are caused by its spherical shape and orbital motion around the Earth not the Sun.
A new moon occurs when the moon is between the Earth and the Sun. Therefore the Moon and the Sun will rise and set together and the brightness of the Sun will obscure the Moon during the day.
Moon Phases

17. The first quarter moon rise at noon.
Phase
Rises
Sets
New
Sunrise
Sunset
Waxing Crescent
Just After Sunrise
Just After Sunset
First Quarter
Noon
Midnight
Waxing Gibbous
Just After Noon
Just After Midnight
Full
Waning Gibbous
Third Quarter
Waning Crescent
Just after Noon
Moon Phases

18. The waxing crescent moon is visible near the western horizon just before sunrise.
The waxing crescent moon is visible near the western horizon just after sunset.
The waxing crescent moon is east of the Sun. It rises and sets a little later than the sun.
Notice that the Sun is setting in the picture.
Moon Phases

19. The waning gibbous moon is visible above the western horizon a few hours before and after sunrise.
The waning gibbous phase follows the full moon, which sets at sunrise. Therefore the waning gibbous moon will set a little after sunrise and will be visible above the western horizon around that time.
Moon Phases

20. The sidereal period or sidereal month is the time it takes the Moon to go through its cycle of phases.
The sidereal month for the Moon is days and is the time it takes for the Moon to orbit the Earth once.
The synodic period or lunar month is the time it takes for the Moon to go through its phases. In other words, the time between two new moons. On average this is about 29.5 days.
Moon Phases

21. The moon moves about 13° westward each night.
Since the Moon orbits the Earth in about days it changes position in the sky from night to night.
In one day the moon will travel 360°/27.32 = 13.1°EASTward.
These two illustrations where created at the same time of day but the illustration on the right was taken a day later
Moon Phases

22. The full moon is highest above the southern horizon for an observer in the Northern Hemisphere at midnight near the summer solstice.
The moon stays close to the ecliptic or path of the Sun, which is at a 23.5° angle to Earth’s equator.
At full moon, the Moon and Sun are on opposite sides of Earth. So when the Sun is high in the sky on one side of Earth the Moon is low in the sky on the other side, and vice versa.
The top illustration is on June 21 ( the summer solstice) and the bottom illustration is on Dec 21 (the winter solstice)
Moon Phases

23. 6.5 thousand or Six thousand five hundred
Write 6.5 x 103 in words
6.5 thousand or Six thousand five hundred
Scientific Notation

24. 6.5 million or Six million five hundred thousand
Write 6.5 x 106 in words
6.5 million or Six million five hundred thousand
Scientific Notation

25. Write 6,600,000 in scientific notation’
6.6 x 106
Scientific Notation

26. Write 0.00085 in scientific notation’
8.5 x 10-4
Scientific Notation

27. Find the product: (8.200 x 10-3)(9.600 x 108)
(8.20 x 9.60) x (10-3 x 108)
78.72 x 108-3
78.72 x 105
7.872 x 106
Scientific Notation

28. Find the quotient: (8.20 x 10-3)/(6.56 x 108)
Scientific Notation

29. How many significant figures does 0.00570 have.
Three
In a decimal fraction, all zeros to the left of the first nonzero digit are not significant but the trailing zeros are.
Significant Figures

30. How many significant figures does 7.00570 have.
Six
For numbers with non-zero digits to the left of the decimal point, all zeros to the right of the decimal point are significant.
Significant Figures

31. Write 0.08900372 to three significant digits.
In a decimal fraction, all zeros to the left of the first nonzero digit are not significant but the trailing zeros are.
Significant Figures

32. Write 6.0000000 using three significant figures.
all zeros to the left of the first nonzero digit are not significant but the trailing zeros are.
Significant Figures

33. Find the quotient and write your answer using the correct number of significant figures: 8.20/6.4
1.3
(8.20 /6.4) =
1.3
When multiplying or dividing, the final
answer will contain the same number of
significant figures as the number with the
fewest significant figures in the problem.
Significant Figures

34. Match the items with the correct values.
Diameter of the Milky Way Galaxy
1 AU
1 parsec
63,240 AU
1 ly
100,000 ly
Distance to nearest star
3.26 ly
Distance from Earth to the Sun
4.24 ly
Size

35. Which arrangement is in order of increasing size, right to left?
galaxy cluster, galaxy, star, solar system
galaxy cluster, star, galaxy, solar system
star, solar system, galaxy, galaxy cluster
solar system, galaxy, star, galaxy cluster 
galaxy, star, star cluster, galaxy cluster
Size

36. The light year is a unit of distance not time.
The light year is the distance light travels in one year. The nearest star, Proxima Centauri, is about 4.2 ly from Earth. The Milky Way galaxy is about 100,000 ly in diameter. And the average distance between Earth and the Sun is 1 AU or about 8 light minutes.
Size

37. Data requires 3 significant figures.
How long in minutes will it take light to travel between two objects 108 million km apart. (Light travels at x 105 km/s)
6.00 minutes
Time = Distance/Speed
Time = (108 x 106 km)/( x 105 km/s)
Time = … s
Time = ( …s)/(60 s/min)
Time = … min
Time = 6.00 min
Data requires 3 significant figures.
Time and Distance

38. Which of the following statements about Galileo's discoveries is INCORRECT?
His observations of the Sun and Moon proved that they where not perfect spheres but had imperfections like mountains and spots.
His observations of the phases of Venus proved Ptolemy incorrect
His observations of sunspots proved the Sun was rotating like Earth.
His observations of the gibbous phases of Venus proved that Venus orbited the sun not Earth.
His observations of Jupiter proved that it was much more massive than Earth.
His observations of the moons of Jupiter proved that the Earth’s moon could travel with Earth in its orbit without being left behind.
Galileo

39. Which of the following statements about Kepler's discoveries is INCORRECT?
Kepler found that the orbits of most planets are ellipses not circles
Kepler found that all circular orbits have and eccentricity of 0.5
Kepler found that the orbits of most of the planets are close to circles so have eccentricities close to zero.
Kepler used the observations of Tyco Brahe to arrive at his conclusions.
Kepler used the method of triangulation using data taken throughout the year.
Kepler

40. Match the concept to the correct definition
Kepler’s 1st Law
Closest point in orbit
Kepler’s 2nd Law
P2=a3
Kepler’s 3rd Law
The planets move in elliptical orbits with the sun at one focus
Apogee
The planets move at different speed depending on their distance from the Sun
Perigee
Farthest point in orbit
Kepler

41. Which of the following statements is true
The apogee of an open orbit, such as a parabolic orbit , does not exist
Mercury , with a higher eccentricity orbit, should change its speed less than Earth or Venus.
A planet will slow down as it approaches the Sun
The transit of Venus, was not useful in early determinations of the astronomical unit.
All orbits have both a perigee and apogee.
Kepler

42. If the mass of a body where doubled, the gravitational force on the body would be
As the mass of a body is doubled the gravitational force is also doubled. However, if the distance is doubled the force is reduced to ¼ the original force. In this slide the force should also include a negative sign.
Newton

43. Which of the following is FALSE
The law of gravitation is universal since it applies to all material object.
Newton’s modification of Kepler’s third law enables us to measure the mass of the Sun
Newton’s gravity explains why Saturn moves so slowly across the sky.
Newton’s second law, F=ma, says that if the force is double on a mass then the acceleration will also double.
Newton’s Laws completely replaced the laws of Kepler
Newton

44. Match the concept with the definition
Newton’s 1st Law
The force of gravity on an object
Newton’s 2nd Law
If one object pushes on another then the second object pushes back on the first
Newton’s 3rd Law
A body will not change its state of motion until a net force acts on it.
Mass
a = F/m
Weight
A measure of an object’s resistance to acceleration
Newton

45. r= the distance from Earth’s center to the object
The circular velocity of an object in orbit around Earth follows the equation vc = What do the variables M and r represent?
M = the mass of Earth
r= the distance from Earth’s center to the object
Do not confuse circular velocity and escape velocity. The escape velocity of an object will always be greater than the velocity needed to keep it in circular orbit.
Newton