ASTR 1101 Exam 1 Quiz Answers
winter solstice
The day with the smallest number of daylight hours over the course of the year for a person living in the northern hemisphere is the
zenith
The direction directly overhead of an observer defines his or her
The Atlantic Ocean is getting smaller with time
The figure shows the continental plates of Earth and the locations of volcanoes and earthquakes. Which statement is false?
directly proportional
The force of gravity that an object has is ? to its mass.
rotational period of the Moon; orbital period of the Moon around Earth
The moon keeps the same hemisphere facing Earth because the ? is equal to the?
false
The observed phase of the Moon changes over the course of one night. True or False?
the reason that a large baked potato takes longer to cool than a small baked potato
The reason that small planets tend to lose interior heat faster than larger planets is essentially the same as?
a spiral galaxy with a disk about 100,000 light-years in diameter and containing between 100 billion and 1 trillion stars
Which of the following best describes the Milky Way?
a region of the celestial sphere
Which of the following best describes the modern definition of a constellation?
magnetism
Which of the following does not have a major effect in shaping planetary surfaces?
the composition of the solar nebula varied between its inner and outer regions
Which of the following is a characteristic of the early Solar System, based on current observations?
a comet in the Oort belt
Which of the following is farthest from the Sun?
higher density interior
Which of the following is not a factor that helps explain Earth's lack of craters compared to the Moon?
Valles Marineris on Mars is a huge canyon, many times deeper than the Grand Canyon here on Earth, which spans one-fourth the circumference of the planet
Which of the following is not considered evidence of cataclysmic impacts in the history of our Solar System?
The comet's speed is greatest when it is nearest the Sun.
Which of the following is true about a comet that is on an elliptical orbit around the Sun?
weight
Which of the following properties of an astronaut changes when he or she is standing on the Moon, relative to when the astronaut is standing on Earth?
most planets orbit at the same speed
Which of the following statements is not an observed pattern of motion in our solar system?
Venus
Which of the following worlds has the greatest difference in temperature between its "no atmosphere temperature and its actual temperature?
Venus
Which of the following worlds has the most substantial atmosphere?
Earth and Venus
Which of the following worlds have the thinnest lithospheres?
plate tectonics and liquid water oceans
Which two factors are critical to the existence of the carbon dioxide (CO2) cycle on Earth?
true
While, night after night, the stars seem not to move relative to each other, they are actually moving in random directions relative to each other with typical velocities of about 70,000 km/hr. True or False?
only dense materials could condense in the inner solar nebula
Why are terrestrial planets denser than Jovian planets?
It is the only one that has both a partially molten metallic core and reasonably rapid rotation
Why does Earth have the strongest magnetic field among the terrestrial worlds?
Mars
looks almost Earth-like, with giant volcanoes, a huge canyon, polar caps
crust
lowest density of Earth's interior; granite, basalt, etc.
troposphere
lowest layer of Earth's atmosphere
Moon, Mercury, Mars, Venus, Earth
Rank the five terrestrial worlds in order of size from smallest to largest.
false
The celestial sphere is just another name for our universe. True or False?
Mercury
made of metal and rock; large iron core; desolate, cratered; very hot in the daytime and very cold in the night
trilobite
A crablike invertebrate that was the dominant organism that got wiped out in the Great Dying
high internal temperature
A planet is most likely to have tectonic activity if it has?
Kuiper belt
A region of the solar system that is just beyond the orbit of Neptune and that contains small bodies made mostly of ice
orbital revolution
A rotation about an external point, the earth around the sun
false
A scientific theory is undisputed fact. True or False?
annular solar eclipse
A solar eclipse during which the Moon is directly in front of the Sun but its angular size is not large enough to fully block the Sun; thus, a ring (or annulus) of sunlight is still visible around the Moon's disk
Oort cloud
A spherical region of comets that surrounds the solar system
Permian-Triassic Extinction
About 250 million years ago. The biggest. Probably a comet or asteroid impact, but could have been caused by a large release of methane gas from the ocean bottom. Around 95% of all marine species went extinct. So did about 70% of known plants, insects, and other land species
4 billion years
Approximately how long after the Solar System formed did it take for oxygen to get to within 80 percent of its present abundance in Earth's atmosphere?
in constant free fall around Earth
Astronauts orbiting Earth in the space shuttle experience so-called weightlessness in space because?
False
At midnight it is sometimes possible to observe the crescent Moon on the meridian.
new and full moons
At which lunar phases are tides most pronounced?
the cosmological principle
Because of ?, we can conclude that gravity works the same way on Mars as it does on Earth.
magnetosphere
Earth's magnetic field
true
Excessive volcanism results in an overall cooling of planet. True or False?
phases of Venus
Galileo's observations that provided that it orbits Sun and not Earth
it operates too slowly
Given the rate at which human activity is increasing CO2 levels, why can we not depend on the natural CO2 cycle to prevent global warming?
false
Historically, there is no link between increased CO2 levels and higher average temperatures. True or False?
true
Homosapiens have existed on Earth for about 150,000 years. This is about 0.1% of the time the dinosaurs roamed the Earth. This means that in about ~1,500,000 years from now we will have lived about ~1% as long as the dinosaurs. True or False?
230 million years
How long does it take our solar system to complete one orbit around the Milky Way Galaxy?
winters would be colder
If Earth's axis were tilted by 35° instead of its actual tilt, how would the seasons be different than they are currently?
8 minutes
If an event were to take place on the Sun, how long would it take for the light it generates to reach us?
Its acceleration is zero.
If an object is moving in circular orbit at a constant speed, which of the following is false?
first quarter
If the Moon is setting at midnight, the phase of the Moon must be?
true
If the distance between Earth and the Sun were smaller, the gravitational force between these two objects would be larger. True or False?
2 weeks
If there is a first quarter Moon out tonight, approximately how long from now will it be in the third quarter phase?
the revolution of Earth around the Sun
If you go out at exactly 9 P.M. each evening over the course of one month, the position of a given star will move westward by tens of degrees. What causes this motion?
4 weeks
If you see a full Moon tonight, approximately how long would you have to wait to see the next full Moon?
illuminated area increasing
In regard to the phase of the Moon, the term "waxing" means
not a scientific idea
In science an idea that cannot be tested is
they would freeze over
In the absence of a greenhouse effect, what would happen to Earth's oceans?
east
In what direction on the horizon does a crescent moon rise?
all the above is true
In what ways is Earth different from the other terrestrial planets?
new moon
Moon between Earth and Sun
waxing
Moon getting more illuminated (right side)
full moon
Moon on opposite side of Earth from Sun
tidal locking
Moon's rotation and orbital period are the same (which is why we only see one side of the moon)
Kepler's third law
More distant planets orbit the sun at slower average speeds, obeying a precise mathematical relationship.
summer solstice
On which day of the year does the Sun reach its northernmost point in the sky?
false
Orbits are always circular. True or False?
billion
Our universe is approximately 13.7 ? years old.
true
Over 99% of all species are extinct. True or False?
epicycles
Ptolemy's theory of what causes retrograde (hypothesis)
Mars's interior has cooled so much its molten core layer no longer undergoes convection.
Recent evidence suggests that Mars once had a global magnetic field. Assuming this is true, which of the following could explain why Mars today lacks a global magnetic field like that of Earth?
stationary, except spinning in-place once per day
Relative to the center of the Earth, a person on the North Pole is ?
Neptune
Similar to Uranus (except for axis tilt); Many moons (including Triton)
Occam's razor
Simpler explanations are more likely to be true than complex ones.
planetesimals
Small planetary objects that form through the action of gravity during the birth of a solar system
Uranus
Smaller than Jupiter/Saturn; much larger than Earth; Made of H/He gas and hydrogen compounds (H2O, NH3, CH4); Extreme axis tilt; Moons and rings
false
Speed and velocity are the same thing. True or False?
part of the planet's interior is liquid
Suppose an earthquake occurs on an imaginary planet. Scientists on the other side of the planet detect primary waves but not secondary waves after the quake. This suggests that:
We would no longer always see nearly the same face of the Moon.
Suppose the Moon's orbit were unchanged, but it rotated faster (meaning it did not have synchronous rotation). Which of the following would be true?
high tides would occur more frequently than they do now
Suppose the Moon's orbit were unchanged, but it rotated faster (meaning it did not have synchronous rotation). Which of the following would be true?
we are seeing Galaxy 1 as it looked at an earlier time in the history of the universe than Galaxy 2
Suppose we look at two distant galaxies: Galaxy 1 is twice as far away as Galaxy 2. In that case?
true
The Moon is constantly falling towards Earth. True or False?
true
The Moon's distance from Earth varies during its orbit. True or False?
the location of Earth in its orbit
The Orion Constellation is visible on winter evenings but not summer evenings because of?
+90 degrees
The altitude of the north star (Polaris) is equal to your latitude on Earth. At what latitude on Earth would the north celestial pole by at your zenith?
Kepler
This astronomer stated that the orbits of planets around the sun were elliptical, the planets do not orbit at a constant speed, and that an orbit is related to its distance from the sun.
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 lunar eclipse?
motions of charged particles
What creates magnetic fields?
the growth of planetesimals from smaller solid particles that collided and stuck together
What do we mean by accretion in the context of planet formation?
the planet appears to move westward with respect to the stars over a period of many nights
What happens during the apparent retrograde motion of a planet?
vulnerability
What is science's greatest strength?
It regulates the carbon dioxide concentration of our atmosphere, keeping temperatures moderate.
What is the importance of the carbon dioxide (CO2) cycle?
the temperatures at which various materials will condense from gaseous form to solid form
What is the primary basis upon which we divide the ingredients of the solar nebula into four categories (hydrogen/helium; hydrogen compound; rock; metal)?
It appears very near the north celestial pole.
What makes the North Star, Polaris, special?
oxygen would disappear from the atmosphere
What would happen if photosynthesis were to disappear on Earth?
6 PM
When does the full moon rise?
spring
When the northern hemisphere experiences fall, the southern hemisphere experiences?
the surface in the region is younger than the surface in more heavily cratered regions
When we see a region of a planet that is not as heavily cratered as other regions, we conclude that?
between the orbits of Mars and Jupiter
Where are most of the known asteroids found?
the planet's distance from the Sun
Whether a planet will be rocky or gaseous depends on what important factor?
radioactivity
Which internal energy source is the most important in continuing to heat the terrestrial planets today?
the remaining meteorite has been identified on the bottom of the Gulf of Mexico
Which is not a reason that we suspect that the extinction of the dinosaurs was caused by an explosive impact by an explosive object?
phases of Venus
Which of Galileo's observations offered direct proof of a planet orbiting the Sun?
Warming would increase the evaporation of the oceans, leading to more water in the atmosphere and more frequent and severe storms.
Why would the weather become more severe as the greenhouse effect increased?
on the northern horizon
You are standing on Earth's equator. Which way is Polaris, the North star?
dwarf planet
a celestial body orbiting a star that is massive enough to be rounded by its own gravity but has not cleared its neighboring regions of planetesimals and is not a satellite
planet
a celestial body that is in orbit around the Sun, has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (shape)
tides
a consequence of Moon's gravity and Earth's rotation
galaxy
a great island of stars in space, all held together by gravity and orbiting a common center
protostar
a large ball or gas not yet hot enough at its core to be a star
protoplanetary disk
a large disk-shaped cloud of dust and gas that the planets and other object in the solar system will form from; flattened disk is a result of angular momentum conservation
star
a large, glowing ball of gas that generates head and light through nuclear fusion
celestial equator
a projection into space of earth's equator onto the celestial sphere
comet
a relatively small and icy object that orbits a star
asteroid
a relatively small and rocky object that orbits a star
solar system
a star and all the material that orbits it, including its planets and moons
Tycho
made the most accurate naked eye measurements ever made of planetary positions, still had the earth as center of universe
horizon
all points 90 degrees away from zenith
gravity
an attractive force between any two objects with mass, acting along the line between them
mass extinction
an episode in evolutionary history where more than 50 percent of all known species living at the time went extinct in a short period of time (less than 2 million years or so)
nebula
an interstellar cloud of gas and/or dust
Newton's first law of motion
an object moves at constant velocity or object stays at rest unless a net force acts to change its speed or direction
moon/satellite
an object that orbits a planet
acceleration
any change in velocity
Kepler's Second Law
as planet moves around its orbit, it sweeps out equal areas in equal times
partial solar eclipse
the Moon only blocks part of the Sun's light
visible light
light you can see
tidal forces
caused by the difference between the strength of the gravitational pull of the Moon and Sun on either side of Earth
scattering
change in photon's direction
lithosphere
crust and part of mantle that "floats"
dissociation
destruction of a molecule
tectonics
disruption of a planet's surface by internal stresses
meridian
line passing through zenith and connecting north and south points on horizon
galactic recycling
elements that formed planets were made in stars and then recycled through interstellar space
erosional debris
erosion can create new features such as deltas by depositing debris
volcanism
eruption of molten rock onto surface
Copernicus
first person to propose a Heliocentric model
Galileo
first scientist to observe the sky with a telescope; overcame major objections to the Copernican view with empirical evidence
Newton's third law of motion
for every force, there is always an equal and opposite reaction force
greenhouse effect
greenhouse gases transmit visible light, allowing it to heat the surface, but then absorb infrared ight from Earth, trapping the heat near the surface
core
highest density of Earth's interior; nickel and iron
exosphere
highest layer in which atmosphere gradually fades into space
reproducibility
if you do an experiment you will be able to do it again
mesosphere
layer above stratosphere, coldest
stratosphere
layer above the troposphere; Earth's natural sunscreen
thermosphere
layer at about 100 kilometers altitude
radio and microwaves
light for communication
gamma rays, x-rays, and ultraviolet rays
light that can hurt you
infrared
light that is thermal
momentum
mass times velocity
mantle
moderate density of Earth's interior; silicon, oxygen, etc.
quarter moon
moon at right angles with Earth and Sun
waning
moon getting less illuminated (left side is lit)
crescent
moon is less than half lit as seen from Earth
gibbous
moon more than half lit as seen from earth
Saturn
most famous for its rings, which are not solid (made of countless small chunks of ice and rock, each orbiting like a tiny moon)
Jupiter
mostly H/He; no solid surface; many moons and rings
Venus
nearly idenitical in size to Earth; surface hidden by cloud; hellish conditions due to an extreme greehouse effect
Hubble-Lamaitre law
objects moving away from each other with velocity proportional to their distance
spring tides
occur during the full moon and new moon, tides are very high and very low
neap tides
occur when the lunar and solar tides partially cancel out, resulting in below average tides
the Sun
over 99.9 percent of solar system's mass; made mostly of hydrogen/helium gas; converts 4 million tons of mass into energy each second
penumbra
part of the Moon's shadow you see in a partial solar eclipse
umbra
part of the Moon's shadow you see in a total or annular solar eclipse
absorption
photon's energy is absorbed
perihelion
point in orbit when object is closest to Sun
aphelion
point in orbit when object is farthest from Sun
celestial sphere
projection of Earth's axes and equator onto space
P waves
push matter back and forth
ionization
removal of an electron
angular momentum
rotational momentum of a spinning or orbiting object
S waves
shake matter side to side
radioactive decay
some isotopes are unstable and decay into other nuclei
nebular theory
states that our solar system formed from the gravitational collapse of a giant interstellar gas cloud—the solar nebula
erosion
surface changes made by wind, water, or ice
conservation of energy
tells us that the gravitational energy of infalling material must be converted into another form of energy
total solar eclipse
the Moon completely blocks the Sun's light
4.6 billion years
the age of our solar system
climate
the average state of an atmosphere
K/T Extinction Boundary
the boundary between the Cretaceous and Tertiary geological periods when the earth experienced a global mass extinction event
light year
the distance light travels in one year
9.5 x 10^12 km
the exact distance in one lightyear
comets
the icy planetesimals that remain in the solar system today
Kepler's first law
the orbit of each planet around the Sun is an ellipse with the Sun at one focus
sidereal period
the orbital period of one object about another measured with respect to the stars
synodic period
the period of rotation or revolution of a celestial body with respect to the sun
Tropic of Cancer and Tropic of Capricorn
the places you can see the Sun directly overhead
nater
the point directly below
zenith
the point directly overhead
convection
the process in which warm material expands and rises while cool material contracts and falls
universe
the sum total of all matter and energy, that is, everything within and between all galaxies
ecliptic
the sun's apparent path through the celestial sphere, inclined 23.5 degrees to celestial equator
cosmological principle
the theory that there is nothing special about our place in the universe
half-life
the time for half the nuclei in a substance to decay
Newton's second law of motion
unbalanced forces cause changes in motion; force=mass x acceleration
seismic waves
vibrations that travel through Earth's interior tells us what Earth is like on the inside
Greenhouse effect
visible light passes through the atmoshere and warms a planet's surface, the atmosphere absorbs infrared light from the surface, trapping heat
