AST 101 Exam #3 Questions And Accurate Answers
Recall that 1 foot = 12 inches. Thus, 1 square foot = - ANSWER 144 square inches
Recall that 1 centimeter = 10 millimeters. Thus, 1 cubic centimeter = - ANSWER 1000
cubic millimeters
The surface area of a small moon is 50,000 square kilometers. This is equal to -
ANSWER 50,000 x 1000^2 square meters
A large boulder has a volume of 1000 cubic meters and a mass of 3,200,000 kilograms.
What is the density of the boulder in grams per cubic centimeter? - ANSWER 3.2 g/cm^3
Intro to Parallax animation In this Introduction to Parallax animation notice that the
parallax is greater (the apparent motion of the object is larger) for the person than for
the trees and that the mountains do not appear to shift at all. Why? - ANSWER The
amount of parallax depends on an object's distance, with greater parallax for nearer
objects.
Which of the following statements best summarizes why stellar parallax occurs?
ANSWER We see nearby stars from different vantage positions in Earth's orbit at
different times of year.
If the ancient Greeks had been able to measure stellar parallax, they would have
discovered that their hypothesis of an Earth-centered universe was incorrect. Why
didn't the ancient Greeks measure stellar parallax? - ANSWER Even for the closest stars
to the Sun, parallax angles are too small to be measurable with the unaided eye.
From their failure in observing stellar parallax, Greeks interpreted that - ANSWER Either
Earth is the centre of universe or stars are much too distant
, Furthermore, as the Parallax Angle animation shows, such measurements can be used
to compute distances to these relatively nearby stars. If we hope to use parallax to
measure distances to even more-distant stars, which of the following telescopes would
be most useful? - ANSWER A telescope that orbits the Sun in the outer solar system
Before we can use parallax to measure the distance to a nearby star we first have to
know: - ANSWER The Earth-Sun distance
Which of the following is a valid way of demonstrating parallax for yourself? - ANSWER
Hold up your hand in front of your face, and alternately close your left and right eyes.
What is the cause of stellar parallax? - ANSWER Earth's orbit around the Sun.
The more distant a star, the: - ANSWER Smaller its parallax angle
About how large is the parallax angle of a star that is 20 light-years away? - ANSWER
0.16 arcsecond
Suppose a star had a parallax angle of just 1 arcsecond. How far away would it be, in
light-years? - ANSWER 3.3 light-years
If star A is closer to us than star B, then Star A's parallax angle is: - ANSWER Larger
than that of Star B
If the star Alpha Centauri were moved to a distance 10 times farther than it is now, its
parallax angle would - ANSWER Get smaller.
Rank (furthest distance from the sun): - ANSWER Pluto, Saturn, Jupiter, Mars, Earth,
Mercury
Rank by mass largest mass: ANSWER Sun, Jupiter, Earth, Mars, Mercury, Pluto
Recall that 1 foot = 12 inches. Thus, 1 square foot = - ANSWER 144 square inches
Recall that 1 centimeter = 10 millimeters. Thus, 1 cubic centimeter = - ANSWER 1000
cubic millimeters
The surface area of a small moon is 50,000 square kilometers. This is equal to -
ANSWER 50,000 x 1000^2 square meters
A large boulder has a volume of 1000 cubic meters and a mass of 3,200,000 kilograms.
What is the density of the boulder in grams per cubic centimeter? - ANSWER 3.2 g/cm^3
Intro to Parallax animation In this Introduction to Parallax animation notice that the
parallax is greater (the apparent motion of the object is larger) for the person than for
the trees and that the mountains do not appear to shift at all. Why? - ANSWER The
amount of parallax depends on an object's distance, with greater parallax for nearer
objects.
Which of the following statements best summarizes why stellar parallax occurs?
ANSWER We see nearby stars from different vantage positions in Earth's orbit at
different times of year.
If the ancient Greeks had been able to measure stellar parallax, they would have
discovered that their hypothesis of an Earth-centered universe was incorrect. Why
didn't the ancient Greeks measure stellar parallax? - ANSWER Even for the closest stars
to the Sun, parallax angles are too small to be measurable with the unaided eye.
From their failure in observing stellar parallax, Greeks interpreted that - ANSWER Either
Earth is the centre of universe or stars are much too distant
, Furthermore, as the Parallax Angle animation shows, such measurements can be used
to compute distances to these relatively nearby stars. If we hope to use parallax to
measure distances to even more-distant stars, which of the following telescopes would
be most useful? - ANSWER A telescope that orbits the Sun in the outer solar system
Before we can use parallax to measure the distance to a nearby star we first have to
know: - ANSWER The Earth-Sun distance
Which of the following is a valid way of demonstrating parallax for yourself? - ANSWER
Hold up your hand in front of your face, and alternately close your left and right eyes.
What is the cause of stellar parallax? - ANSWER Earth's orbit around the Sun.
The more distant a star, the: - ANSWER Smaller its parallax angle
About how large is the parallax angle of a star that is 20 light-years away? - ANSWER
0.16 arcsecond
Suppose a star had a parallax angle of just 1 arcsecond. How far away would it be, in
light-years? - ANSWER 3.3 light-years
If star A is closer to us than star B, then Star A's parallax angle is: - ANSWER Larger
than that of Star B
If the star Alpha Centauri were moved to a distance 10 times farther than it is now, its
parallax angle would - ANSWER Get smaller.
Rank (furthest distance from the sun): - ANSWER Pluto, Saturn, Jupiter, Mars, Earth,
Mercury
Rank by mass largest mass: ANSWER Sun, Jupiter, Earth, Mars, Mercury, Pluto
