AST 111 EXAM CH. 1 3 UPDATED ACTUAL QUESTIONS AND CORRECT ANSWERS

AST 111 EXAM CH. 1 3 UPDATED ACTUAL QUESTIONS AND
CORRECT ANSWERS

Question:
Put the following into perspective: the size of our solar system; the distance to nearby stars; the size of the
Milky Way Galaxy; the size of the observable universe. Rank from largest to smallest. To rank items as
equivalent, overlap them.
Answer:
The observable universe, The Milky Way Galaxy, Distances to nearby stars, and The Solar system

Question:
Light-year:
Answer:
The distance that light travels in 1 year, which is about 9.46 trillion kilometers.

Question:
Astronomical Unit:
Answer:
The average distance between Earth and Sun, which is about 150 million kilometers.

Question:
The Andromeda Galaxy is faintly visible to the naked eye. When you look at the Andromeda Galaxy, the retina
of your eye is absorbing light that has traveled through space for ______ to reach you.
Answer:
about 2 ½ million years

Question:
Suppose that someone in the Andromeda galaxy had a super-telescope through which they were looking at
Earth right now. They would see Earth ______.
Answer:
as it was about 2 ½ million years ago

Question:
Which of the following correctly lists our "cosmic address" from small to large?
Answer:
Earth, solar system, Milky Way Galaxy, Local Group, Local Supercluster, universe;

Question:
An astronomical unit is
Answer:
Earth's average distance from the Sun.

Question:
The star Betelgeuse is about 600 light-years away. If it explodes tonight,
Answer:
we won't know about it until 600 years from now.

, Question:
The total number of stars in the observable universe is roughly equivalent to:
Answer:
the number of grains of sand on all the beaches on Earth.

Question:
Earth rotates once each ______ on its axis and orbits the Sun once each _______. The ecliptic plane is the
plane defined by _______'s orbit around the ________. Axis tilt of a planet is the amount that its ________ is
tipped relative to a line perpendicular to the ecliptic plane.
Answer:
Day, Year, Earth, Sun, and Axis

Question:
■ In the demonstration, 360 of rotation (one full rotation) represents a sidereal day. You can actually measure
the length of the sidereal day by measuring the time from when __________ crosses your meridian on one day
(or night) until it crosses the meridian on the next day (or night). Check all that apply.
Answer:
the star Sirius the star Vega

Question:
As shown in the figure, a solar day requires about an extra 1° of rotation, or a total of about 361° of rotation for
Earth. Therefore, a solar day is longer than a sidereal day by about __________.
Answer:
1/360 of 24 hours

Question:
Which of the following changes would cause the solar day to be shorter (rather than longer) than the sidereal
day?
Answer:
Reversing the direction of Earth's rotation

Question:
Suppose that Earth orbited the Sun 10 times as fast as it actually does but kept the same rotation period it has
now. Which of the following would be true?
Answer:
The sidereal day would still be 23 hours, 56 minutes, but the solar day would be a little over 24 1/2 hours.

Question:
The Moon takes about 1 month to orbit Earth (more precisely, about 27 1/3 days), and it travels in the same
direction that Earth orbits the Sun. Therefore, during the time it takes the Moon to complete one orbit around
Earth, Earth moves __________ around its orbit of the Sun.
Answer:
About 1/12th of the way.

Question:
Based on your answer to Part E, the time from one new moon to the next must be _________.
Answer:
longer than the Moon's actual orbital period by about 1/12 of the 27-day orbital period