astro 5 final
Choose the latitude on Earth this star trail picture was most likely taken at:
+5 degrees (near the equator)
a theory is
- a hypothesis that has withstood many attempts to falsify it - tied to know physical laws - able to make testable predictions
The eccentricity of the majority of the planetary orbits in our Solar System is close to
0
If Mercury has an orbital period of about 88 days, what is its average distance from the Sun?
0.4 AU
at what latitude is the north celestial pole at your horizon?
0°
Which object, masses listed, will experience the greatest acceleration if the same force is applied to all of them?
1 kg
If there is a full Moon out tonight, approximately how long from now will it be in the third quarter phase?
1 week
the number 123,000 written in scientfic notation
1.23 x 10^5
what time does a third quarter moon rise?
12 midnight
Most planets currently found around other stars are
2 to 10 MEarth, which is smaller than Neptune.
At which of the possible times below could the waxing gibbous moon be seen rising?
3 pm
Kepler's third law says that a comet with a period of 160 years will have a semimajor axis of
30 AU
If you see a full Moon tonight, approximately how long would you have to wait to see the next full Moon?
4 weeks
One of the nearest stars is Alpha Centauri, whose distance is 4.4 light-years. The time it takes light to travel from Alpha Centauri to us is
4.4 years
If Jupiter has an orbital period of 12 years, what value is closest to its average distance from the Sun?
5 AU
At a latitude of +50°, how far above the horizon is the north celestial pole located?
50°
The dwarf planet named Eris orbits the Sun with a semimajor axis of 68 AU. Using Kepler's third law, Eris's orbital period is
560 years
at approximately what time does a full moon rise?
6 P.M.
If an event were to take place on the Sun, how long would it take for the light it generates to reach us?
8 minutes
Suppose an asteroid had an orbit with a semimajor axis of 4 AU. How long would it take for it to orbit once around the Sun?
8 years
Approximately how much mass was there in the protoplanetary disk out of which the planets formed, compared to the mass of the Sun?
< 1%
In the figure, a planet orbits the Sun. During which of the three sections (A, B, or C) will the planet have the lowest average velocity?
A
In the figure, a planet orbits the Sun. The line connecting the planet and Sun sweeps out three areas labeled A, B, and C, during three different time intervals. If the duration of the time intervals are the same (meaning t2 - t1 = t4 - t3 = t6 - t5), how are the sizes of these areas related?
A, B, and C have the same size
where is the asteroid belt located
Between Mars and Jupiter
If you were to specify your address in the universe, listing your membership from the smallest to largest physical structures, it would be
Earth, Solar System, Milky Way, Local Group, Laniakea Supercluster, the universe.
_________ hypothesized that planetary motions could be explained by a force arising from the attraction between the mass of the planet and the Sun that decreased with the square of the distance between them.
Isaac Newton
gas giants
Jupiter, Saturn, Uranus, Neptune
Which lists the terrestrial planets in the correct order?
Mercury, Venus, Earth, Mars
_________ was the first person to introduce a mathematical heliocentric model of the Solar System from which accurate predictions could be made of planets' positions.
Nicholas Copernicus
If you have a stuffy nose, a fever, chills, and body aches and a doctor treats you for the flu rather than four separate diseases that account for each of your symptoms, this is an application of
Occam's razor
Why do the terrestrial planets have a much higher fraction of their mass in heavy chemical elements (as opposed to lighter chemical elements) than the giant planets?
Terrestrial planets are low in mass and high in temperature, thus their lighter chemical elements eventually escaped to the outer reaches of the Solar System.
Which of the following is not a characteristic of the early Solar System, based on current observations?
The initial composition of the solar nebula varied between its inner and outer regions.
Why do the outer giant planets have massive gaseous atmospheres of hydrogen and helium whereas the inner planets do not?
The outer planets grew massive quickly enough to gravitationally hold on to these gases before the solar wind dispersed the accretion disk.
When astronomers began searching for extrasolar planets, they were surprised to discover Jupiter-sized planets much closer than 1 AU from their parent stars. Why is this surprising?
These planets must have formed at larger radii where temperatures were cooler and then migrated inward.
Which of the following is not considered evidence of cataclysmic impacts in the history of our Solar System?
Valles Marineris on Mars is a huge scar, many times deeper than the Grand Canyon, which spans one-fourth the circumference of the planet.
Which of the following best describes why the Moon goes through phases?
We see only part of the lit-up half of the Moon depending on its position relative to Earth and the Sun.
Have astronomers detected any Earth-sized planets around normal stars yet?
Yes, the Kepler spacecraft is just starting to find them.
On December 1, at noon, you are looking toward the south and see the Sun among the stars as shown in the Figure bellow. Two students are discussing where the Sun would appear among the stars at 3 PM that afternoon. Which one is correct?
You're forgetting that stars and constellations will rise in the east, move through the southern sky and then set in the west just like the Sun. So the Sun will still be in Scorpius at 3 PM.
A small body in the solar system that is made of rock, ice and dust and has a tail when it gets close to the sun is ________________.
a comet
Why have astronomers using the radial velocity method found more Jupiter-sized planets at a distance of 1 AU around other stars than Earth-sized planets?
a jupiter-sized planet exerts a larger gravitational force on the star than an earth-sized planet, and the Doppler shift of the star is larger
what is a protostar?
a large ball of gas not yet hot enough at its core to be a star
The time it takes light to cross Neptune's orbit is closest to which of the following?
a night's sleep
Most asteroids are closest in shape to
a potato
what is a meteorite?
a rock that fell to earth from space
As a car drives around a corner at constant speed, the car is
accelerating because the direction is changing
A type of eclipse in which the Sun appears as a bright ring is called a
annular solar eclipse
which is the best depiction of a moon?
any natural satellite of a planet or asteroid
one of the central assumptions in astronomy is that the physical laws of nature
are the same everywhere in the universe
Consider a star that is more massive and hotter than the Sun. For such a star, the habitable zone would
be located outside 1AU
Our universe is approximately 13.7 _________ years old.
billion
What is a planetesimal?
bodies of ice and rock 100 meters or more in diameter
gravity is
both B and C
Two rocks (call them S and T) are released at the same time from the same height and start from rest. Rock S has 20 times the mass of rock T. Which rock will fall faster if the only forces involved are each rock's mutual gravitational attraction with Earth?
both rocks will fall at the same rate
Declination is a measure of a star's location relative to
celestial equator
Kepler's second law says that if a planet is in an elliptical orbit around a star, then the planet moves fastest when the planet is
closest to the star
Whether or not a planet is composed mostly of rock or gas is set by
combination of A, B, and C
Light-hour is a measure of __________
distance
At the center of the geocentric model of the Solar System is the
earth
what position must the earth and moon be located in order for a lunar eclipse to occur
earth in middle, moon behind
The apparent path of the Sun across the celestial sphere over the course of a year is called the
ecliptic
The smallest grains of dust stick together in an accretion disk by which force?
electricity
When Earth catches up to a slower moving outer planet and passes it like a faster runner overtaking a slower runner in an outside lane, the planet
exhibits retrograde motion
Which is not a scientific goal of NASA's Kepler mission?
finding intelligent life on other planets
If tonight the Moon is in the waxing gibbous phase, in 3 days what is the most likely phase of the Moon?
full phase
How did Ptolemy "fix" the geocentric system?
he introduced epicycles
In the ________ model of the Solar System, ________ motion is only an apparent, not a real, motion.
heliocentric; retrograde
the solid form of a volatile material is generally referred to as a(n)
ice
In regard to the phase of the Moon, the term waxing means
illuminated area increasing
If the distance between Earth and the Sun were cut in half, the gravitational force between these two objects would
increase by 4
If it is wintertime right now and it is just after the winter solstice, how does the height of the Sun at noon change over the next several months?
increases
In 1994, dozens of fragments of Comet Shoemaker-Levy 9 collided with
jupiter
An observer located outside our Solar System, who monitors the velocity of our Sun over time, will find that the Sun's velocity varies by ± 12 m/s over a period of 12 years, due to
jupiter's gravitational pull
the mass of all known asteroids combined is approximately equal to
less than one-third the mass of the moon
During a lunar eclipse the Moon can appear red. This is caused by
light traveling through earth's atmosphere
Right ascension is a measure of a star's location on the celestial sphere that is most closely similar to which measurement of location on Earth?
longitude
the force of gravity that an object has is directly proportional to its
mass
comets and asteroids are
material left over from the formation of the planets
What have astronomers and geologists studied to arrive at the same conclusion about the Earth's origins?
meteorites
what position must the earth and moon be located in order for a solar eclipse to occur
moon in middle, earth behind
If you are observing a partial solar eclipse, you must be standing in the
moon's penumbra
If you are lucky enough to see a total solar eclipse, you must be standing in the
moon's umbra
Galileo's telescopic observations of the _________ led him to conclude that the heliocentric model of the Solar System was correct
moons of jupiter and phases of venus
For a person who lives at a latitude of +40°, when is the Sun directly overhead at noon?
never
During which lunar phase do solar eclipses occur?
new
You and a friend go outside to view the stars at midnight tonight. Six months later, you go outside to find the stars in exactly the same position in the sky as when you and your friend viewed them. What time is it? Assume you can see the stars at any time, day or night.
noon
If the Sun is located at one focus of Earth's elliptical orbit, what is at the other focus?
nothing
Which of the following is not true about orbits?
orbits are always circular
If the star Polaris has an altitude of 35°, then we know that
our latitude is +35°
the moon probably formed
out of a collision between earth and a mars-sized object
The time it takes a planet to complete one full orbital revolution is commonly known as its
period
Kepler's third law is a relationship between an orbiting object's
period and semimajor axis
Detecting a planet around another star using the transit method is difficult because the
planet must pass directly in front of the star
Retrograde motion is seen when ____________ due to Earth's motion
planets change the direction in which they move across the night sky
Which property of an extrasolar planet cannot be determined using the Doppler effect?
radius
The fact that Kepler's heliocentric model of the Solar System predicted _________ more easily and accurately than the geocentric model is an illustration of how scientific theories evolve by the scientific method.
retrograde motion of planets
asteroids are primarily composed of
rock
Two rocks (call them S and T) are a distance of 50 km from one another. Rock S has 20 times the mass of rock T. Considering only their mutual gravitational force, which rock will accelerate faster in response to gravity?
rock T
all the inner planets are
rocky
The Moon undergoes synchronous rotation, and as a consequence the
rotational period of the moon equals the orbital period of the moon around earth
A scientific theory can be shown to be wrong if
scientists gather new data that contradict its predictions
The average distance between a planet and the Sun is given by the _________ of its elliptical orbit.
semimajor axis
When the northern hemisphere experiences fall, the southern hemisphere experiences
spring
Newton's first law states that objects in motion
stay in motion unless acted upon by an unbalanced force
solar and lunar eclipses are rare because
the Moon's orbital plane is tipped by 5.2° relative to Earth's orbital plane
The ecliptic is defined by the motion of _________ in the sky.
the Sun
In the absence of air friction, a 0.001-kg piece of paper and a 0.1-kg notebook are dropped from the same height and allowed to fall to the ground. How do their accelerations compare?
the accelerations are the same
Which of the following is true about a comet that is on an elliptical orbit around the Sun?
the comet's speed is greatest when it is nearest to the sun
Because of _____________, we can conclude that gravity works the same way on Earth as it does on Mars.
the cosmological principle
The distance used in Newton's law of gravitation is
the distance between the centers of the objects
what is the habitable zone?
the distance from a star where liquid water can exist
A partial lunar eclipse occurs when
the moon passes through part of the earth's shadow
Galileo observed what the geocentric astronomers viewed as imperfections. These observations helped Galileo to show that the heliocentric model was the more accurate model. Which was not an observation of Galileo?
the moons of saturn
Astronomers argued that the heliocentric model of the Solar System was simpler than the geocentric model, based on
the observed retrograde motions of the planets
What is the most important factor in determining whether or not a planet will be rocky like terrestrial planets or gaseous like giant planets?
the planet's distance from the sun
If you go out at exactly 9 P.M. each evening over the course of 1 month, the position of a given star will move westward by tens of degrees. What causes this motion?
the revolution of Earth around the Sun
If you measured the orbital period of the Moon and the distance between Earth and the Moon, then you could calculate if you used Newton's full version of Kepler's 3rd Law?
the sum of the masses of earth and the moon
the cosmological principle states that
the universe looks the same everywhere as long as you look on large enough scales
Astronauts orbiting Earth in the space shuttle experience so-called weightlessness in space because
they are in constant free fall around earth
where are asteroids found?
throughout the solar system
The Kepler mission is designed to search for extrasolar planets using the _________ method.
transit
Which method can be used to determine the radius of an extrasolar planet?
transit
Earth-sized planets have been found using the _________ method(s).
transit and Doppler shift
inner planets are rocky, relatively closely spaced and dense (T or F)
true
A solar-powered spacecraft is traveling through the Moon's shadow. Which part(s), if any, of the Moon's shadow will cause the spacecraft to completely lose power?
umbra
the darkest part of the moon's shadow is the
umbra
earth's twin (size and mass)
venus
How would the number of hours of sunlight and the height of the Sun in the sky at noon change (if at all) over the course of the year for locations on the equator?
very little - because the amount that these locations are tilted toward or away from the Sun changes very little throughout the year
If the Sun set below your Western horizon about 2 hours ago, and the Moon is barely visible on the Eastern horizon, what phase would the Moon be in at this time and location?
waning gibbous
You are in the library studying for an exam, and at 3pm you notice out your window that the Moon is directly due south. Which phase do you see the Moon displaying?
waxing crescent
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?
weight
A solar eclipse occurs: (choose the most correct answer)
whenever there is a NEW moon AND the moon is on the ecliptic
Earth is closest to the Sun when the Northern Hemisphere experiences
winter
If Earth's axis were tilted by 5° instead of its actual tilt, how would the seasons be different than they are currently?
winters would be warmer
scientific notation is used in astronomy primarily because it allows us to
write very large and very small number in a convenient way
The direction directly overhead of an observer defines his or her
zenith
The meridian is defined as an imaginary circle on the sky on which lie the
zenith and the north and south celestial poles
