AST 115 Exam 1
How far from Earth is the Moon?
1 light second
Approximately, what is the age of the Universe?
14 billion years
How long does it take our solar system to complete one orbit around the Milky Way Galaxy?
230 million years
How many arcseconds are in one degree?
3,600
How far from Earth is the nearest star besides the Sun?
4.2 light years
Approximately, what is the age of the Earth?
4.5 billion years
How many arcminutes are in one degree?
60
How many arcseconds are in one arcminute?
60
If your mass is 60 kg on Earth, what would your mass be on the Moon?
60 kg
If traveling at the speed of light, approximately how far could you travel in one second?
7 times around the earth
How far from Earth is the Sun?
8.3 light minutes
On the scale of the cosmic calendar, in which the history of the universe is compressed to 1 year, how long has human civilization (i.e., since ancient Egypt) existed?
A few seconds
Which of the following statements about scientific models is true?
A model can be used to explain and predict real phenomena
Kepler's second law, which states that as a planet moves around its orbit it sweeps out equal areas in equal times, means that
A planet travels faster when it is nearer to the Sun and slower when it is farther from the Sun
On a scale where the Sun is about the size of a grapefruit and the Earth is about 10 meters away, how far away are the nearest stars besides the Sun?
About the distance across the United States
What causes the apparent retrograde motion of the planets?
As Earth passes another planet, the other planet appears to move backward with respect to the background stars, but the planet's motion does not really change
How did Eratosthenes estimate the size of Earth in 240 B.C.?
By comparing the maximum altitude of the Sun in two cities at different latitudes
Gasoline is useful in cars because it has
Chemical potential energy
The controversial book of this famous person, published in 1543 (the year of his death), suggested that Earth and other planets orbit the Sun.
Copernicus
If the sun is a grapefruit (10cm), what is the size and distance of Earth?
Earth is a poppy seed about 10 meters away.
In which direction does a quarter moon rise?
East
A solar eclipse occurs only when the Moon is new.
False
Columbus was the first person to discover that Earth is round.
False
Earth is always precisely 1 AU from the Sun.
False
Kepler deduced his laws of planetary motion once Newton had published his universal law of gravitation.
False
The Moon and Sun are approximately the same physical size.
False
The Ptolemaic model of the solar system was useless for predicting planetary positions.
False
The solar system contains about 250 billion stars.
False
There is no gravity in space.
False
When energy is converted from one form to another, a tiny amount is inevitably lost.
False
If the Moon is setting at 6 A.M., the phase of the Moon must be
Full
When we see Venus in its full phase, what phase would Earth be in as seen by a hypothetical Venetian?
Full
Galileo observed which of the following phases of Venus?
Full, crescent, new, gibbous
He discovered that Jupiter has moons.
Galileo
One of the "nails in the coffin" for the Earth-centered universe was
Galileo's observations of the moons of Jupiter
Which of the following is not a phase of the Moon?
Half moon
How does the Space Shuttle take off?
Hot gas shoots out from the rocket and, by conservation of momentum, the shuttle moves in the opposite direction
The principle of Occam's Razor states that
In explaining natural phenomena, the simplest explanation consistent with the observations is to be preferred
On a cosmic calendar, in which the history of the universe is compressed into 1 year, when did the dinosaurs become extinct?
In late December
What makes the North Star, Polaris, special?
It appears very near the north celestial pole.
He discovered that the orbits of planets are ellipses.
Kepler
The ultimate source of energy that powers the Sun is
Mass energy of hydrogen fusing into helium
The mass of Jupiter can be calculated by
Measuring the orbital period and distance from Jupiter of one of Jupiter's moons
At approximately what time would a full moon be on your meridian?
Midnight
In the Ptolemaic model of the solar system, Venus should exhibit which of the following phases?
New and crescent
The fact that Voyager 10 continues to speed out of the solar system, even though its rockets have no fuel, is an example of
Newton's First Law of Motion
Has Polaris always been the "North Star"?
No, because the Earth's axis slowly changes the direction it points
You are standing on Earth's equator. Which way is Polaris, the North star?
On the Northern horizon
Which of the following statements about the Milky Way Galaxy is not true? Our solar system is located very close to the center of the Milky Way Galaxy. One rotation of the galaxy takes about 200 million years. The galaxy is about 100,000 light-years in diameter. It contains between 100 billion and 1 trillion stars.
Our solar system is located very close to the center of the Milky Way Galaxy.
He developed a system for predicting planetary positions that remained in use for some 1,500 years.
Ptolemy
How many galaxies are there in the observable universe?
Roughly (within a factor of 10) the same as the number of stars in our galaxy)
Which of the following is largest? size of Pluto's orbit size of a typical galaxy 1 light-year distance to the nearest star (other than our Sun)
Size of a typical galaxy
Which of the following is smallest? 1 AU 1 light-second size of a typical star size of a typical planet
Size of a typical planet
If you see Polaris directly overhead at midnight, you must be at
The North Pole
Why is it summer in the Northern Hemisphere when it is winter in the Southern Hemisphere?
The Northern Hemisphere is tilted toward the Sun and receives more direct sunlight
The tides on Earth are an example of
The Universal Law of Gravitation
An astronomical unit (AU) is
The average distance between Earth and the Sun
Which of the following is the reason for the solar day being longer than a sidereal day?
The combined effect of the rotation of Earth and its orbit about the Sun
The Earth is instantly replaced in its orbit by a speck of dust. Which statement best describes the subsequent orbital motion of that piece of dust?
The dust particle will continue in the same orbit as the Earth did, orbiting the Sun in 1 year
You are standing on a scale in an elevator. Suddenly you notice your weight decreases. What do you conclude?
The elevator is accelerating downwards
Where does the energy come from that your body uses to keep you alive?
The foods you eat
Orion is visible on winter evenings but not summer evenings because of
The location of Earth in its orbit
In addition to the conditions required for any solar eclipse, what must also be true in order for you to observe a total solar eclipse?
The moon's umbra must touch the area where you are located
What conditions are required for a lunar eclipse?
The phase of the Moon must be full, and the nodes of the Moon's orbit must be nearly aligned with Earth and the Sun
What conditions are required for a solar eclipse?
The phase of the Moon must be new, and the nodes of the Moon's orbit must be nearly aligned with Earth and the Sun
What is the ecliptic plane?
The plane of Earth's orbit around the Sun
What happens during the apparent retrograde motion of a planet?
The planet appears to move eastward with respect to the stars over a period of many nights
0 degrees Kelvin is
The temperature at which all random particle motion stops
If the Moon is rising at midnight, the phase of the Moon must be
Third-quarter
Why did Ptolemy have the planets orbiting Earth on "circles upon circles" in his model of the universe?
To explain the fact that planets sometimes appear to move westward, rather than eastward, relative to the stars in our sky
A lunar eclipse occurs only when the Moon is new.
True
One light-year is about 10 trillion kilometers.
True
The Moon and the Sun are approximately the same angular size.
True
The Moon is constantly falling toward Earth.
True
The solar system is a member of a galaxy containing approximately 250 billion stars.
True
Which of the following critical features of the heliocentric model leads to Venus exhibiting a full range of phases?
Venus passes on the far-side of the sun from the Earth's perspective
The total number of stars in the observable universe is about
the same as the number of grains of sand on all the beaches on Earth
