astronomy chapter 1-3 review midterm
What is the flux ratio of two stars whose difference in magnitude is 2.6?
10.8
Calculate the angular diameter of the Moon with these known facts: Moon's linear diameter = 3480 km Moon's average distance from Earth = 384,000 km number of arc seconds in 1 radian = 2.06 × 105
1870 arc seconds
If star A is 14.5 times brighter than star B, then what is their magnitude difference?
2.9
Uranus is approximately 3 × 109 km away from the Sun. What is the distance in astronomical units?
20 AU
You need to drive to a research site to collect some samples. The site is 250 miles away. What is the approximate distance in kilometers?
400 km
Which best represents 5,362,000,000 kilometers in scientific notation?
5.362 × 109 km
You discover a new star that is 352,800 AU away. What is the distance in light years?
5.6 ly
If the Moon crosses Earth's shadow at the center of the umbra, how long will the entire eclipse last from start to finish?
6 hours
The star Wolf 359 is 7.7 light years away. What is that distance in kilometers?
7.28 × 1013 km
Jupiter is located approximately 5.2 AU away from the Sun. What is the distance in kilometers?
7.8 × 108 km
In 1928, the International Astronomical Union (IAU) established _______________ official constellations with carefully defined boundaries that together include every part of the sky.
88
Approximately how long does it take light to reach the Earth from the Sun?
8min
From which language did the majority of star names originate?
Arabic
Which is an example of an asterism?
Big Dipper
The discovery that whether peas are smooth or wrinkled is an inherited trait was made by
Mendel
Which of these planets is just 0.39 AU from the Sun?
Mercury
spherical, rocky, or gaseous bodies that orbit a star
Planet
The star Vega has a magnitude of 0.03. Using the accompanying figure which object is brighter than Vega?
Polaris
What happens during a penumbral lunar eclipse?
The Moon partially enters the penumbra.
Why can't the Moon always pass through the center of the umbra?
The Moon's orbit is inclined by 5 degrees to the plane of Earth's orbit.
What does a waning crescent moon mean?
The changing Moon between third quarter and new moon
What is a new moon?
The lunar phase in which sunlight illuminates only the far side of the Moon
Why are extrasolar planets difficult to detect?
They are generally small. They are faint. They are too close to the glare of their respective parent star. all of these
Why is the term "arc" used to describe units of measure for angular distance?
To avoid confusion with the minutes and seconds of time
Due to the cycle of precession, in 12,000 years, which star will replace Polaris as the guiding North Star?
Vega
Which of these planets is approximately the same size as Earth?
Venus
Which planet is often called our most brilliant "morning star"?
Venus
the angular distance across an object, from one edge to another
angular diameter
In the above image, what is the observer measuring?
angular distance
The angle between two lines extending from your eye to two objects in the sky
angular distance
The farthest point in the Moon's orbit
apogee
a less formally defined grouping of stars
asterism
Review the accompanying figure. Where does the celestial equator always meet the horizon?
at the east and west points
Even though modern astronomers know that stars are scattered through space at different distances, they still use what scientific model to describe celestial locations in the sky?
celestial sphere
a scientific model of the sky
celestial sphere
Which part of the Sun is observable during a total solar eclipse?
chromosphere
When can Sirius, a famous star of the Northern Hemisphere, be observed?
during winter
a small object that orbits the Sun beyond Neptune
dwarf planet
What is the apparent path of the Sun against the background of stars?
ecliptic
planets orbiting stars beyond our own solar system
extrasolar planet
In a given constellation, the star designated with the Greek letter α is always brighter than the star designated with the Greek letter β.
false
In ancient times, constellation boundaries were well defined.
false
Jupiter, Saturn, Uranus, and Neptune are only located at a distance of 1 AU or less from the Sun.
false
Most individual star names come from Latin and have been altered through passing centuries.
false
Our Solar System formed 14 billion years ago with the Big Bang.
false
The Moon has a dark side that is never lit by the Sun.
false
The geometry of a solar eclipse is the same as that of a lunar eclipse.
false
The sky appears to rotate eastward around Earth each day, but that is a consequence of the westward rotation of Earth.
false
To see a solar eclipse, you have to be in Earth's shadow.
false
Uranus is one of a group of dwarf planets and other small objects that have been discovered circling the Sun beyond Neptune.
false
Any location on the Moon is sunlit for three weeks and is in darkness for one week as the Moon rotates.
false
As the illuminated part of the Moon grows larger from new to full, it is said to "wane".
false
Astronomers describe the brightness of stars using the brilliance scale.
false
Earth spins completely upright like a giant top.
false
The Moon moves slowly against the background of the constellations.
false
The Universe consists of the Sun, its family of planets, and some smaller bodies such as moons, asteroids, and comets.
false
The nadir marks the point of the celestial sphere directly above your head.
false
The scale of apparent visual magnitudes extends into negative numbers to represent the faintest objects in the sky.
false
The scientific method is a simple, mechanical way of grinding facts into understanding.
false
The seasons are caused by Earth's orbit moving closer to or farther from the Sun.
false
When the Moon is totally eclipsed, the Moon is illuminated by some sunlight reflected by Earth's atmosphere.
false
Which is a unit used to measure angular distance?
feet
A lunar eclipse can only occur when the Moon is ____
full
What does this image resepent?
galaxy
a great cloud of stars, gas, and dust held together by the combined gravity of all of its matter
galaxy
Astronomers use the _______________ alphabet to identify the bright stars in a constellation in approximate order of brightness.
greek
What is the Sun made up of?
hot gas
provides a measurement range for the brightness of stars
magnitude scale
You are analyzing driveway lengths within your neighborhood and surrounding neighborhoods, and your data is to be presented to the city council. Which would be the most appropriate unit of measurement?
meters
Review the accompanying figure and identify point C.
nadir
The point of the celestial sphere directly under your feet
nadir
Solar eclipses must occur at __________ moon.
new
A solar eclipse can only occur when the Moon is ____
new
The two points at which the Moon's orbit crosses the ecliptic
nodes
Eclipses can occur only when, viewed from Earth, the Sun is near one of the ____ of the Moon's orbit.
nodes
Review the accompanying figure and identify point B.
north celestial pole
The region of partial shadow where sunlight is dimmed
penumbra
The closest point in the Moon's orb
perigee
When the Earth is at ________, it is at its closest point to the Sun in its orbit.
perihelion
Due to the high temperatures of the gas, what color do prominences appear as during a solar eclipse?
pink
Which list is in order of increasing size?
planet, star, solar system, galaxy, Universe
An plasma loop emerging from the solar surface is called a ___________.
prominence
If Earth rotated about its axis completely upright, what would we fail to experience?
seasons
The orbital period with respect to the stars of about 27 days
sidereal period
In Figure 1, what is the pointer indicating?
spiral arm
Within the Northern Hemisphere, the vernal equinox marks the start of ____.
spring
a self-luminous ball of hot gas
star
A complete cycle of lunar phases of 29.53 days
synodic period
How many Saros cycles does it take for the same eclipse to occur at about the same location on Earth?
three cycles
What is the safest way or method to observe a solar eclipse?
through a pinhole projection
A completely eclipsed Moon
totality
A "larger" Moon on the horizon is an optical illusion.
true
A convenient method for writing very large numbers is to use scientific notation.
true
A planet is massive enough to be rounded by its own gravity.
true
Because Earth's axis of rotation is inclined 23.4 degrees from vertical, the Sun moves into the northern sky in the spring and into the southern sky in the fall.
true
Flux is a measure of the light energy from a star that hits a collecting area of one square meter in one second.
true
The constellations are an ancient heritage handed down for thousands of years as ways to tell stories of mythical heroes and monsters.
true
The most widely accepted system of measurement is the metric system.
true
There is one side of the Moon that can never be seen directly by observers on Earth.
true
We are living in one of Earth's ice ages.
true
Earth is approximately 13,000 km in diameter.
true
Humanity is very new to the Universe.
true
In most months, there are no eclipses.
true
Our calendar divides the year into 30-day periods in recognition of the synodic cycle of the Moon.
true
Predicting an eclipse is easy because all you have to do is keep track of where the Moon crosses the ecliptic.
true
Scientists try to form hypotheses that explain how nature works.
true
The International Astronomical Union established 88 constellations that represent a defined area of the sky.
true
The angular diameters of the Moon and Sun vary slightly because the orbits of the Moon and Earth are slightly elliptical.
true
When the full Moon passes through Earth's shadow, the eclipse is visible from anywhere on Earth's dark side.
true
How many times does the Moon cross the ecliptic each month?
twice
What is the length of time half of the Moon stays in sunlight per full rotation?
two weeks
The region of total shadow
umbra
The illuminated portion of the Moon decreases
wanes
The illuminated portion of the Moon increases
waxes
Review the accompanying figure (Figure 2-4) and identify point A.
zenith
the point of the celestial sphere directly above your head
zenith
Examine the accompanying figure. Which term would be the correct scientific designation for Polaris in Ursa Minoris?
α Ursae Minoris
What is Earth's distance from the Sun?
1.0 AU
If two stars have a magnitude difference of 5, what is their flux ratio?
100.0
Since Mars is 1.5 AU from the Sun, how long would it take for sunlight to reach the surface of Mars?
12 min
Since the Moon is about 0.5 degrees in angular diameter, about how far does it move in 24 hours across the background of the constellations?
13 degrees
Between now and 2024, in which year will there be no opportunities for a solar eclipse?
2018
When did life first appear on Earth?
3.4 billion years ago
Why do prominences appear pink during a solar eclipse?
Because of the high temperature of the gases
What is the very first step of the scientific method?
Form a hypothesis
Which is an asterism of Pegasus?
Great Square
What is an asterism?
Less formally defined group of stars outside the official 88 constellations
Which is the correct order of the planets, moving from closest to the Sun to farthest from the Sun?
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
Betelgeuse is the brightest star of which constellation?
Orion
Which ancient astronomer recorded the magnitude of stars in his star catalog and was used successfully by astronomers for generations?
Ptolemy
What astronomical period takes 18 years 11 1/3 days to complete?
Saros cycle
What gives the Moon a coppery glow during a total eclipse?
Sunlight refracted through Earth's atmosphere
What did the IAU establish in 1928?
The IAU recorded 88 constellations with defined boundaries.
What happens during a partial lunar eclipse?
The Moon only partially enters the umbra.
What creates a total lunar eclipse?
The Moon passes completely through Earth's umbra.
What happens every 29.5 days?
The Moon's synodic cycle
What does a waxing gibbous moon mean?
The changing Moon between first quarter and full moon
What produces the lunar phases?
The changing direction of sunlight
What process do scientists use to determine how nature works?
The scientific method
What was the purpose of the IAU establishing 88 official constellations?
To define boundaries for constellations including every part of the sky
The ____ of the Moon and Sun vary slightly because the orbits of the Moon and Earth are slightly elliptical.
angular diameter
At what point is the Moon farthest away from Earth?
apogee
The Big Bang is a theory describing the
beginning of the Universe
Earth's rotation is connected with a very slow celestial motion that can be detected only over
centuries
What is the name of constellations that appear to never rise or set?
circumpolar constellations
Solar System
consists of a star with orbiting planet
named group of stars with finite boundaries in the sky
constellation
What did the International Astronomical Union classify Pluto as in 2006?
dwarf planet
The apparent path of the Sun against the background of stars
ecliptic
The measure of light energy striking one square meter per second
flux
What unit would best describe the linear diameter of a planetary body?
kilometers
What unit of measurement is used to describe extraordinary large distances, such as the distance of other stars from our own?
ly
At what point is the Moon closest to Earth? apogee
perigee
Earth's rapid rotation makes its axis sweep out the shape of a cone, like a heavy top slowing down. This motion is known as ____.
precession
What is the cause for the slow movement of reference marks, such as the celestial poles and equator, to move across the sky?
precession
The chromosphere is often marked by eruptions on the solar surface called ____.
prominences
Day and night cycles are caused by the ____ of Earth.
rotation
The diamond ring effect is a characteristic of which phenomena?
solar eclipse
If the Moon is too far from Earth during a solar eclipse, the _____ does not reach Earth's surface.
umbra
What are the two parts of a shadow during an eclipse?
umbra and penumbra
