Astronomy VCU fall final part 2
A star is found to have absolute magnitude 9 and apparent magnitude 24. How far away is it?
10,000 parsecs.
Suppose that the color and behavior of a star identify it as a type that we know has absolute magnitude 4.8. If the star's apparent magnitude is found to be 9.8, how far away is it?
100 parsecs.
The diameter of the Milky Way Galaxy is close to
100,000 light years.
We can use the pointer stars in the Big Dipper to locate a point in the sky near the
North Celestial Pole.
The Celestial Sphere is
a map of the stars.
Type Ia supernovas have the following properties:
a spectrum with no hydrogen lines and a standard maximum brightness.
The number of moons of Jupiter is
at least 62.
According to the current model of the early history of the Solar System, the formation of the Oort Cloud happened
at the same time as the the rain of comets that supplied water to the Earth and other planets.
The motion of tectonic plates is driven by
convection currents in the Earth's mantle.
The red subgiant stage of a star is best described by
dropping temperature and constant brightness.
The statement that lunar material is much "dryer" than Earth material refers to the absence of
hydrated minerals.
The density of rock is about 3000kg/m³. The densities of the Jovian planets are
less than 3000kg/m³ because they are mostly gas.
When the helium fuel runs out at the center of a low-mass star like our Sun,
moves off of the horizontal branch.
Suppose that a comet is spotted while it is still far from the Sun (beyond the orbit of Mars). The tail of this comet is most likely
not yet formed.
Satellites such as the International Space Station orbit above most of the Earth's atmosphere because
there is no air friction to slow the satellite down.
The ancient Greeks were able to estimate the distance from the Earth to the Sun by using
the quarter phases of the Moon.
The first indication that Cygnus X-1 might be a black hole was
the rapid fluctuations in its X-rays.
The diffraction limit of a telescope refers to the effect of
the wavelength of light.
Once a space probe has gotten far enough from the Earth, it can reach the inner planets by
using its rocket motor and the gravity of various planets to change its speed and direction.
The surface of Pluto can best be described as
varied with ice mountains and almost no craters at all.
A planet whose atmospheric pressure is exactly at the triple point of water and whose surface temperature has a range that includes the triple point will have
water as ice or vapor, depending on the temperature.
Which of the following statements is falsifiable?
Nobody owns a green cell phone.
The thickest part of the visible Milky Way is near the constellation
Sagittarius.
Which of the following temperatures is closest to what you might expect on the planet Uranus?
-350°F
A solar sail is a large sheet of light-reflecting plastic spread on an extremely low-mass framework and attached to a spacecraft. Sunlight exerts a force on the sail and moves the spacecraft. Suppose the spacecraft has a total mass of 500kg (including the sail) and sunlight exerts a total force of 5N on the sail. What will be the acceleration of the spacecraft?
0.01m/s².
In the Earth's atmosphere, the percentage that is Carbon Dioxide is roughly
0.04%.
The mass of a carbon atom is 12.00amu while the mass of a deuterium atom is 2.014amu. If a gamma ray photon splits a carbon atom into six deuterium atoms, how much energy is converted into mass?
0.084amu
As of 2018, how many space probes had flown past Uranus closely enough to take detailed pictures?
1.
The average radius of the Earth's orbit is
1.0 au.
What total force will cause an object with a mass of 1kg to gain 10 meters per second every second?
10 Newtons.
Suppose that a flash of lightning from a cloud 2000 meters away is followed by a clap of thunder two seconds later. Assume that the light arrived in a negligible time and calculate the speed of the sound waves.
1000m/s
A star at a distance of 10,000pc should have an apparent brightness equal to its absolute brightness multiplied by
10⁻⁶.
A star whose apparent brightness is 10⁻⁴ times that of a first magnitude star would have magnitude
11.
Suppose that you lift an object by exerting an upward force of 22 Newtons on it. If gravity exerts a force of 10 Newtons downward on the object, what is the total force on the object?
12 Newtons.
The Earth's distance from the Sun is defined to be 1 astronomical unit. Neptune is about 30 astronomical units from the Sun. An object in the Inner Oort Cloud might be at a distance from the Sun of
15,000 astronomical units.
The first human landing on the Moon was Apollo 11 in
1969.
Barnard's Star shows a heliocentric stellar parallax of almost exactly 1/2 seconds of arc. The distance from our Sun to Barnard's Star is
2 parsecs.
Compared to the frequency of photons absorbed during a transition from a -6ev state to a -4ev state, transitions from the -6ev state to a -2ev state would correspond to absorbing photons whose frequency is
2 times as high.
It now (2016) appears that, except for the universe itself, the largest structure in nature has a size of approximately
300 million light years.
Our own Sun has an absolute visual magnitude of 4.8. A starship that travels 10 parsecs from our Sun and looks back at the Sun will see it as having apparent visual magnitude
4.8.
Assume that the Hubble constant is 72 km/s/Mpc. If a galaxy is 10Mpc away, how fast is it moving away from us?
720km/s
Just before sunrise, you might find
A waning crescent Moon rising in the east.
The closest star to Earth (other than the Sun) is part of a multiple star system called
Alpha Centauri.
The brightest star in the constellation Orion might be named
Alpha Orionis.
In the Hertzsprung-Russelll Diagram shown, which point represents a star of type B with absolute magnitude +10?
D
In current Earth life, the self-copying molecule that contains the information needed to construct and operate a life-form is
DNA.
The velocities with which stars and gas clouds orbit the center of our galaxy is measured by observing their
Doppler shifts.
A galaxy that is a featureless flattened ball of stars would be called a type
E7.
Although most records from that time were lost in the burning of the Great Library at Alexandria, most historians say that the first actual measurement of the Earth's circumference was made in the 3^{rd} century BCE by
Eratosthenes of Cyrene.
Which of these moons has patterns of cracks in the ice on its surface. indicating a subsurface ocean?
Europa.
Which of the following spectral types corresponds to the star with the lowest surface temperature?
G5
The statement that the orbit of each planet is an ellipse with the Sun at one focus is due to
Kepler.
The cluster of galaxies that our own galaxy belongs to is called the
Local Group.
Which of the following planets has just two moons?
Mars
Which of these sequences places the inner planets in the correct order from the Sun, from the closest to the farthest?
Mercury, Venus, Earth, Mars (farthest)
The angle between the rotation axis of a planet and the perpendicular to the plane of its orbit is called its "axial tilt." Which of these planets has an axial tilt that is less than one degree?
Mercury.
The temperature on Jupiter is
Much colder than anywhere on Earth.
Galileo was the original discoverer of
Newton's First Law of Motion.
Fred reports that a special arrangement of wire coils can draw electrical power from the air. He really built the device and was very surprised when it really did produce electrical power. The most likely outcome of his report is that:
Other people build the proposed device. It generates power just as he said and he becomes famous as the discoverer of a source of endless electrical power.
Within our own Milky Way Galaxy, our sun is a typical member of
Population I.
Which of the following features in the light reflected from a planet would indicate the presence of Earth-type plants (rather than just colored rocks) on its surface?
Red light is not reflected, but infra-red light is strongly reflected.
You are looking down on the Earth from a spacecraft hovering far above. After watching for a while, you notice that, from your perspective, it is rotating clockwise. The part of the Earth that is directly below you must be the Earth's
South Pole.
The path of the Sun on the Celestial Sphere is called
The Ecliptic.
Compare the magnitude of the acceleration of Earth's Moon relative to the Earth to the acceleration of falling objects on the surface of the Earth.
The Moon's acceleration is smaller.
From his observations of the phases of Venus, Galileo concluded that
The Ptolemaic Model is wrong.
The Ptolemaic model of the Solar system accounted for the daily rising and setting of the Sun by assuming that
The Sun moves around the Earth once a day.
Jupiter failed to become a star because
The proto-Sun's final collapse blew all the gas away.
One model for the formation of the Solar System is that the planets formed from a cloud of material extracted from the Sun by a chance encounter with a passing star.
This model incorrectly predicts planets orbiting out of the plane of the Sun's equator.
Which of the following astronomers is regarded as an early example of government-supported Big Science.
Tycho Brahe.
Of the following methods for eliminating an asteroid threat, which one would be affected least by the unknown composition and condition of the asteroid?
Use the gravitational attraction of a massive spacecraft to pull the asteroid off course.
The star Wemadeit shows a stellar parallax angle of 0.4 seconds of arc while the star Waytoofar shows a stellar parallax angle of 0.3 seconds of arc. From this, you can conclude that
Wemadeit is closer to our Sun than Waytoofar.
The Cassini-Huygens spacecraft
Went into orbit around the planet Saturn.
The Earth's core consists of
a central core of solid iron and an outer core of liquid iron.
A nova occurs when
a white dwarf steals fuel from a neighbor.
So far (as of 2018), the planet Venus has been visited by
about 28 successful space probes.
Titan has
an atmosphere whose temperature and pressure permit liquid methane.
The theory that dark matter is not real and is just a a problem with our theory of gravity has been falsified by
an observation of what happens when clusters of galaxies collide.
One difficulty with the microfossils that were found in the martian meteorite ALH84001 is that they
are too small.
Our Sun sends out intense streams of charged particle radiation. Most of these charged particles
are trapped by the Earth's magnetic field for a while and then strike the atmosphere over the poles.
On the present surface of Mars, water has been confirmed to exist
as ice at the poles and water vapor in the atmosphere.
On a world with liquid water but no life, carbon dioxide in the atmosphere would
decrease as the water dissolves it to form an acid that combines with surface rocks.
The intense magnetic field of the Crab pulsar causes its rate of spin to
decrease.
Far from the Sun, a comet is basically a
dirty lump of frozen gas and ice.
Nuclei such as protons do not fuse at low temperatures because their speeds are not enough to overcome their
electrical repulsion.
A brown dwarf shines primarily with
energy left over from its formation.
The magnetic field of Earth's Moon is
essentially zero.
Here is the Drake Equation. In this equation, L stands for the
expected lifetime of a communication-capable civilization.
The Oort Cloud is located
far beyond the orbit of Pluto.
The absorption and re-radiation of infrared light by gases such as carbon dioxide is the key process in the
greenhouse Effect.
The range of distances of a planet from its primary star that will permit the existence of liquid water on the planet's surface is called the
habitable zone.
If we detect that a star is sometimes moving toward us and sometimes moving away and also find that this pattern repeats at regular intervals, we know for sure that the star
has at least one object of unknown type orbiting around it.
The troposphere is where one finds
hurricanes.
One indication that there is a lot of invisible matter in the outer halo of our galaxy is that stars in that region orbit with velocities that
increase with increasing distance from the center.
If the acceleration of an object is zero, its speed
is not changing.
The gravitational attraction of the Earth for other objects,
is smaller for objects farther from the Earth but never vanishes entirely.
The planet Neptune was located because
its gravity disturbed the orbit of Uranus.
The debris of long-dead comets causes
meteor showers.
Near the center of the Milky Way there is an intense radio source whose mass is approximately three
million solar masses within several light days of the center.
In comparison to RR Lyra variables, Cepheid variable stars are
more luminous and less common.
The arms of a spiral galaxy such as ours stand out because they contain
most of the brightest stars.
At the center of our Milky Way galaxy, neighboring stars are typically
much closer together than neighbors of our sun..
The Earth's Moon is about 1/4 the size of the Earth. When compared to other planets and their moons, the Earth's Moon is
much larger than we would expect.
As seen from North America, the constellation Ursa Major
never sets.
Galileo said that once an object is set in motion, it will keep moving at the same speed so long as
no force is acting on it.
A converging lens will send all of the light that it receives from a distant star through a point
on the focal plane of the lens.
In a Hertzsprung-Russell diagram, the hottest stars are found
on the left side.
Black holes are often discovered by observing the shifting of spectral lines in an ordinary star that they are orbiting. Careful measurements of the shifting spectral lines can provide
only a minimum mass for the black hole.
Which of the following particles would be repelled by a positron?
proton.
Planets move mostly eastward relative to the distant stars but, once during each trip around the Celestial Sphere, they loop back westward for a while. This motion is called
retrograde motion.
Aristotle said that the amount of force on a moving earthly object determines its
speed.
Spectroscopic parallax uses
stellar spectra to locate stars in the HR diagram.
Galaxies are organized into clusters and other large non-uniform structures that
stop with voids and filaments (made of superclusters), which are themselves uniformly distributed.
The time when the noon sun is highest in the sky is called
the Summer Solstice.
A hydrogen bond is the result of
the electrical attraction between a hydrogen atom on one molecule and an oppositely charged part of another molecule.
The changing phases of the Moon are caused by
the motion of the Moon around the Earth.
One way to change the course of an asteroid is to place a `mass driver' on it. The mass driver is really just a catapult that throws things (like rocks for example) away from the asteroid. The force that acts on the combined object (mass driver plus asteroid) is actually exerted by
the rocks that the catapult throws.
The position of a protostar on an HR diagram changes because
the size and temperature of the protostar change.
The ancient Greeks argued that the Earth cannot be moving because such a motion would cause apparent shifts in the positions of stars. This argument was wrong because
the stars are so far away that the shifts due to the Earth's motion are extremely small.
Venus retains a dense carbon dioxide atmosphere because
there is no liquid water there.
Pathfinder was the first
to use airbags to land on Mars.
