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Astronomy 1101 W/ Dr. Thompson - OSU

Terms in this set (264)

You are Standing on Earth, at rest. An object passes you at nearly the speed of light. Special Relativity says that you will see:
Time pass more slowly on that object than on Earth
Collisions between galaxies are common because:
Galaxy separations are only about 20x their diameters
If the density parameter omega_0 was much larger than 1, and if there was no Cosmological Constant (dark energy), the universe would be expected to:
Eventually collapse in a big crunch
Just before the epoch of Recombination, the Universe was hotter than 300k, and as a result:
Neutral hydrogen could not exist
Two cepheid stars A and B have the same apparent brightness, but A has a pulsation period 5 times longer than B . From this information you can conclude that:
Star A is further away than Star B
The apparent recession velocities we measure for the majority of galaxies in the universe are due to the:
Expansion of spacetime between galaxies
An early success of General Relativity was that it explained
The anomalous precession of the perihelion of Mercury
Population III stars are a hypothesized class of stars formed from
metal-free primordial gas
A primary piece of evidence for the existence of dark energy comes from the observed
non-linearity in the hubble diagram at high redshift
In newton's formulation of physics, space and time are viewed as
separate and absolute
Einstein's principle of Isotropy means that, when viewed on the universe's largest scales, the
universe looks statistically the same to all observers
when we compare the true total mass of a galaxy cluster with the mass measured by adding up all the stars in all the galaxies of the cluster, we find that the true cluster mass
is much larger than its stars would suggest
one major success of the big band model for the formation of the universe is that it predicts the
cosmic microwave background radiation
if two spiral galaxies collide with each other, they are likely to
merge and form an elliptical galaxy
our galaxy, the milky way, is a
spiral galaxy
a galaxy is
a large number of stars held together by gravity
in the past, the universe was
hotter, denser, smaller, younger
as a group , population II stars are ______ compared to population I stars
older, more metal-poor, and have less ordered orbits
the cosmic microwave background we see today is the redshifted relic of the
blackbody radiation from the hot early universe
the hubble constant measures
the current expansion rate of the universe
a galaxy consisting primarily of old stars, and very little (if any) cool gas and dust, is probably a
elliptical galaxy
shapeless observations of RR Lyrae stars in globular clusters neglected absorption of starlight by interstellar dust. this made the globular clusters appear
more distant than they really were
Einstein's principle of homogeneity means that, when viewed on the universe largest scales, the
average density of the universe is the same everywhere
what is a supercluster?
a cluster of clusters of galaxies
during the time before the epoch of big bang Nucleosynthesis the universe was
too hot for nuclei like helium and lithium to exist
Galaxy A has a redshift of 0.1. Galaxy B has a redshift of 0.2. From this information and the existence of the Hubble law, you can conclude that
Galaxy B is two times further away than Galaxy B
A surprising and counter-intuitive requirement of Special Relativity is that
the speed of light is the same for all observers
imagine we knew the true luminosities of each of the objects below. which would be the most generally useful for measuring the distances to far away galaxies?
type-Ia supernova explosions
One of the central postulates of special relativity is that
uniformly moving observers agree on the laws of physics
the speed of light is the same for all observers
the iron nuclei in your blood were produced in...
white dwarf supernovae
which of the following is an experimental verification of general relativity?
the bending of light around massive bodies
the hubble law is an empirical correlation between... (aka what is the observation that we call the Hubble Law?)
the recession velocity and distance of galaxies; The more distant a galaxy is the faster it appears to recede away from us.
spiral arms are usually sites of ______ in spiral galaxies
recent star formation
taken together, our current estimates of the hubble constant (H_0) and the density parameter (Omega_0) tell us that the age of the universe is
about 14 billion years old
the effect of a massive dark matter halo on a spiral galaxy is that _____ compared to what you would predict from the starlight alone
the outer parts of the galaxy rotate faster
the oxygen nuclei in the water you drink were produced in...
massive star supernovae
if new observations showed conclusively that the hubble constant is *smaller* than previously thought, then this fact by itself would imply that the universe is
older than we thought
the "big bang" is the name for the
beginning of our universe
a spiral galaxy's spheroid is a two-part structure consisting of a ______ and a _______.
compact bulge, diffuse halo
one major success of the big bang model for the formation of the universe is that it predicts the
abundance of helium in metal poor stars
what is the name of the sequence of nuclear reactions that generates the energy in the cores of main sequence stars that are 10 times the mass of the sun
the CNO cycle
stars with masses larger than 8 times the mass of the sun will most likely end their lives as...
neutron stars
after formation, the main stages of evolution for a six solar mass star are...
main sequence, red supergiant, blue supergiant, red supergiant, O-Ne-Mg white dwarf
the hertzsprung-russell diagram shows the relation between ______ of the stars
luminosity and temperature
what is a pulsar?
a rapidly rotating neutron star
T/F A star is in thermal equilibrium when the amount of energy generated in the core is balanced by the transport of that energy to the surface to be radiated away as starlight.
true
hydrogen gas emits at 656 nm in your lab. you observe the same hydrogen spectral feature in a distant star's spectrum at 650 nm. from this, you can conclude that...
the star is moving toward earth at high velocity
stars with masses between 4 and 8 times the mass of the sun will most likely end their lives as
oxygen-neon-magnesium white dwarfs
during the evolution of a low mass star up the red giant branch on the HR diagram, the star burns
hydrogen in a shell and has an inert helium core
the event separating the red giants phase from the horizontal branch phase of stellar evolution for low mass stars is the...
helium flash
the apparent brightness or flux of an object depends on...
the inverse square of the distance
if two stars have the same apparent brightness, the star closer to the sun will generally have...
lower luminosity
a main sequence star that is about 3 times more massive than the sun is about 81 times more luminous. its main sequence lifetime is therefore approximately
27 times shorter than the sun's
the sun will spend about 10 Gyr on the main sequence, but only 100 Myr on the horizontal branch (aka red clump). why?
helium fusion is less efficient than hydrogen fusion
if the sun suddenly collapsed and became a black hole, without changing its mass, the earth would
continue to orbit just as it does now
gamma rays have higher energies than radio waves. both are emitted by a nearby star at the same time. which arrives first?
they arrive at the same time
what information is necessary and sufficient to measure the luminosity of a nearby star?
apparent brightness and distance (from parallax)
a star cluster is a useful natural 'laboratory' for studying stellar evolution because the stars in a cluster all
have similar age and similar distance
the sun is a ...
main sequence star
all else being equal, if you ____ the density or ____ the temperature of a gas the pressure increases
inc, inc, inc
if you gently heat the air inside of a toy balloon, the balloon will
grow in size as the pressure increases
three stars are of the A spectral type. list them in order of increasing radius
aka
Three stars have surface temperatures of 10,000K. List them in order of INCREASING radius.
white dwarf, main sequence star, giant star, supergiant
why do we expect neutrino emission from the sun?
neutrinos are a by product of hydrogen fusion
which of the following is not a property of main sequence stars?
they undergo Helium fusion in their cores
in the horizontal branch (or red clump) phase of low mass stellar evolution, which element undergoes nuclear fusion in the stellar core?
helium
suppose all of the following have a mass of 1 solar mass. list them all in order of DECREASING size
white dwarf, neutron star, black hole
what is the name of the sequence of nuclear reactions that generates the energy in the cores of main sequence stars that are half the mass of the sun?
the proton-proton (PP CHAIN)
a planetary nebula represents the transition between what two stages in the life of a star?
asymptotic red giant and white dwarf
luminosity is proportional to mass to the 4th power for main sequence stars. IF luminosity was instead proportional to M^2, how would the lifetime of stars relate to mass, M?
the lifetime would be proportional to 1/M
a white dwarf that accretes from a binary companion can exceed _____ and become a type of _______
the chandrasekhar mass, supernova
all main sequence stars...
convert hydrogen to helium in their cores
in following the main sequence on the H-R diagram in the direction of increasing temperature, one is also following a sequence of
increasing mass
two stars are at the same distance and have the same temperature, but they have different radii. the larger stars will be
brighter
parallax can be used to find a star's ___ and is a result of ____
distance, the earth's orbital motion
jill watches as jack falls toward a black hole. jack fires a yellow laser beam that flashes every second by his watch as he falls. as jack gets closer to the black hole, jill sees the flashes getting....
redder and fainter, and less frequent
the mass of a black hole is
located at singularity
during the evolution of a low-mass star up the asymptotic red giant branch on the HR diagram, the star burns ____ as well as ___ in shells, and it has an inert ____ core.
hydrogen, helium, carbon oxygen
after formation, the main stages of evolution for a sun-like star are....
Main sequence, red giant, horizontal branch/red clump, asymptotic red giant (asymptotic giant branch), CO white dwarf
hydrostatic equilibrium is a balance between pressure and gravity T/F
TRUE
The energy radiated by solitary white dwarfs comes from
residual heat (thermal energy)
two primary discoveries by galileo were
the sun's spots and jupiter's moons
in the copernican system, why is venus only at most 46 degrees away from the sun on the sky? because venus...
orbits the sun on a circle with radius less than 1 AU
in ancient Egypt, Eratosthenes used the length of ____ at noon on the summer solstice to estimate the ______
a shadow cast by a stick, circumference of earth
In measuring the angle of the Sun relative to a vertical stick in Alexandria at noon on the day of the summer solstice, Eratosthenes found 7 degrees and 12 arcminutes. Imagine that everything about that experiment was the same, except that the angle measured was smaller (for example: 3 or 5 degrees). What would that smaller angle imply?
A larger value for the Earth's circumference.
in Newtonian physics, a planet in a perfectly circular orbit at constant orbital speed experiences no force T/F
FALSE
Newton's generalization of kepler 3rd law implies that if the earth's mass were increased to nearly that of these, but the semi-major axis of its orbit was held constant....
the orbital period would decrease
in a binary star system, star A has 5 times the mass of star B. The center of mass of the system lies
closer to star A than to star B
Copernicus explained day and night as resulting from
the earth spinning on its axis
the failure to detect parallaxes of stars during copernicus's time and before, was used as evidence that
the earth does not move
on the day of a full moon, the moon rises
at sunset
the Copernican heliocentric system violated which ancient greek idea?
that the earth is fixed and unmoving
from the law of gravitation, newton deduced that the shape of orbit is always _____ with the ______ at one focus.
conic section, center of mass
newton's 3rd law would require that the strength of the gravitational force of the earth pulling on the moon is
equal to that of the moon pulling on the earth
you are facing due south in columbus at 10 pm. scorpius is front of you, near the horizon. you are instantly transported due south 1,000 miles. scorpius now appears....
higher in the sky relative to the horizon
what is an AU
the average distance between the earth and the sun
one method of finding planets around other stars is to look for transits. this method is biased towards finding
large planets at small semi major axes
how many arcseconds are there in one degree?
60 x 60
aristarchus used the duration of the _____ relative to the duration of the _____ to determine the distance to the moon in terms of earth radii
lunar eclipse, lunar month
over a night, as seen from the surface of earth, the stars appear to move in what way?
appear to rise in the east, set in the west
if the force of the sun's gravity were suddenly turned off
the earth would continue to move, but in a straight line
newton's law of gravitation states that the attractive force between any two masses is in proportion to the product of ____, and in inverse proportion to ______
the two masses, square of the distance between them
two objects separated by a distance d are pulled apart to distance of 8d. how has their gravitational force changed?
decreased by a factor of 64
kepler's third law states that the square of the orbital period of a planet is proportional to
its orbital semi major axis cubed
object A has a mass of 1 kg. object B has a mass of 20 kg. if the same force is applied to both,
B will have 1/20th the acceleration of A
In Aristarchus's measurement of the earth-sun distance, why is the angle between the moon-earth-sun so close to 90 degrees?
the sun is far away compared to earth-moon distance
one method of finding planets around other stars is by direct detection. this method is biased towards finding
large planets at large semi-major axis
keeper's 2nd law of orbits states that the line between the sun and a planet sweep out equal areas in equal times. newton showed this behavior is a consequence of...
angular momentum conservation and gravity
galileo's discovery of the moons of jupiter was significant support for the heliocentric system because it showed
there were other centers of motion besides earth
does the moon always appear to be the same size? does the moon rotate?
no, yes
two bodies (a and b) have the same physical size but b is twice as far away as a. which appears smaller and by how much?
object b appears two times smaller than object a
ptolemy's ____ model used epicycles to explain ______
geocentric, retrograde motion of planets
retrograde motion is the apparent ______ on the sky with respect to background stars over the course of ______
backward motion of planets, earth's year
galileo showed that massive bodies in a gravitational field fall with
constant acceleration, independent of mass
aristarchus measured the distance to the sun relative to the moon by measuring the ____ between the ____ when the moon was _____
angle, moon-earth-sun, half illuminated
galileo's observations of the sun strongly indicated that
it roates
the astronomer tyco brahe was known for his
accurate observations of planet positions
what was copernicus's revolutionary idea concerning the solar system?
the sun is at its center, the planets orbit the sun
do you ever see a crescent moon at midnight? do you ever see a full moon during the day?
no,, yes
the largest blow galileo dealt to the Ptolemaic (geocentric) system was to show that Venus appears
nearly full when farthest away
Two bodies (A and B) have the same angular size from your position, but B is twice as far away as A. Which is physically larger?
Object B
Two stars A, B have the same mass, but A has smaller radius than B. Which has the HIGHER escape velocity? Two planets C, D orbit the same star, but C has a smaller semi-major axis than D. Which has the SMALLER orbital circular velocity?
A, D
What common behavior is shared by all main sequence stars (like the Sun)?
Fusion of hydrogen into helium in the core.
A star that starts out equal in mass to the Sun will end its life as a _______. A star that starts out with 15 times the mass of the Sun will end its life as a ________. (Neither star is in a binary star system. Pick the best answer.)
Carbon-Oxygen white dwarf; neutron star or black hole
A white dwarf star is closest in size to
the Earth
What sits at the very center of the Milky Way Galaxy and other large galaxies? How do we know?
A supermassive black hole; We observe stars orbiting a massive invisible object.
What causes light to shine from some black holes?
Gas heats up due to as it accretes onto the black hole, producing radiation.
What is a black hole?
Any object dense enough that light cannot escape from it.
A planetary nebula is
the ejected envelope of an aging star similar in mass to the Sun.
Compared to low mass stars, high mass stars are
less common, hotter, and shorter lived.
What causes a white dwarf star to explode as a supernovae?
The white dwarf collides with another star or "accretes" matter from a companion star.
General Relativity is a theory of
gravity
One major success of the Big Bang model for the formation of the Universe is that it predicts the
abundance of helium in metal-poor stars
Big Bang nucleosynthesis took place when the universe was approximately
1 minute old.
If the density parameter Ω0 was SMALLER than 1, and if there was no Cosmological Constant (dark energy), the universe would be expected to
expand forever, but at an ever-decreasing rate.
Shapley's observations of RR Lyrae stars in globular clusters neglected absorption of starlight by interstellar dust. This made the globular clusters appear
more distant than they really are.
The 'spiral nebula' Andromeda is
the most nearby massive spiral galaxy, like the Milky Way.
The Great Debate contrasted which hypotheses about the universe?
The Nebular and Island Universe hypotheses.
You are standing on Earth, at rest in your rest frame. Jane passes you at nearly the speed of light with a photon clock. Special Relativity says that you will see
time pass more slowly on Jane's rocket than on Earth.
Andrea Ghez and Reinhard Genzel won the Nobel Prize for their work to
establish the nature and mass of the Milky Way's central supermassive black hole.
Immediately after it finishes life on the main sequence, the Sun will ...
ascend the red giant branch.
What is the ultimate fate of a star like the Sun that is about 1 solar mass and not in a binary star system?
It will end up as a ...
Carbon-Oxygen white dwarf
What happens when a white dwarf exceeds the "Chandrasekhar mass limit" due to either collision/merger with another white dwarf, or via accretion from a stellar companion?
it may explode in a white dwarf supernova.
Which will have a longer main sequence life time, Proxima Centauri (0.2 solar masses) or Sirius (2 solar masses)?
Proxima Centauri
What supports a white dwarf star against gravitational collapse?
Electron degeneracy pressure.
Massive stars end their lives as ...
neutron stars or black holes.
Does fusing Helium release energy? Is Helium fusion more or less efficient than Hydrogen fusion?
Yes. Less.
A neutron star has about 1.5 times Sun's mass and is about the size of ...
a city like Columbus, OH.
What basic obstacle has to be overcome to fuse two atomic nuclei?
The repulsion of the positive charges of the nuclei.
How do we measure the luminosity of a star?
Pick the most direct answer.
From the apparent brightness and distance (from parallax).
What is the Sun made of mostly?
hydrogen and helium
A star whose spectrum peaks in the infrared range of the electromagnetic spectrum is
cooler than the sun
What is the HR diagram?
A plot of temperature or color index versus luminosity for stars.
What is the Milky Way?
A band of light in the sky at night that is our home galaxy viewed from within its disk.
Consider two main sequence stars, star CAT and star DOG.
Star CAT has a luminosity 100 times higher than that of star DOG.
Star CAT has a mass 2 times larger than that of star DOG.
How does the lifetime of star CAT compare to that of star DOG?
Star CAT lives 50 times LESS than star DOG.
The stars Proxima Centauri and Betelgeuse have the same surface temperature.
However, the luminosity of Betelgeuse is 1,000,000 times the luminosity of Proxima Centauri.
What can you say about the relative size of Betelgeuse and Proxima Centauri?
The radius of Betelgeuse is 1,000 times the radius of Proxima Centauri.
An RR Lyrae is an example of a __________. RR Lyraes in globular clusters were used by Shapley to investigate the size and shape of __________.
Standard candle; The Milky Way.
Betelgeuse is 100,000 times more luminous than the Sun. Its surface glows a red color.
Which of these statements is true?
Pick ALL that apply.
Betelgeuse has a lower surface temperature than the Sun.
Betelgeuse has a much, much bigger size than the Sun.
What is the main property of a star that determines where that star sits on the "main sequence"?
mass
The Sun is located in what part of the Milky Way?
the disk
What is a "standard candle"? Why are they useful?
An astrophysical object whose luminosity is known. We can use this information and the observed brightness to derive the distance to objects.
How do we infer the existence of dark matter?
Pick the simplest, most direct answer.
Galaxies spin too quickly to be explained just by the matter than we can see.
The Hubble constant (given the symbol H0) can be found by
dividing a galaxy's radial velocity by its distance
What is our preferred explanation for the Hubble Law?
Each unit of empty space expands over time. The empty space in the universe is expanding.
Before any stars or galaxies formed, but after Big Bang nucleosynthesis, the normal matter in the Universe consisted of ...
mostly hydrogen and helium and not many heavier elements.
We measure the rotation speed of a galaxy at a radius, R. What can we infer from this information?
The mass of the galaxy inside the radius R.
What is most abundant form of the matter in the universe?
Dark matter.
How does the Hubble law tell us about the age of the Universe?
By "reversing" the observed expansion we can tell when all galaxies were next to each other.
The Fermi paradox may imply that...
Interstellar space travel is practically impossible.
Advanced civilizations are short-lived.
We are alone in the Milky Way.
The accelerated expansion of the universe as a result of Dark Energy causes very distant galaxies to have
Recession velocities smaller than the linear Hubble Law would predict.
One piece of evidence supporting the idea that our Universe went through "Inflation" at a very early epoch in its history is that the...
Cosmic Microwave Background is highly smooth & uniform.
How would the Hubble Law look different for someone living in the distant galaxy "Arp 220," which is on the other side of the Virgo Cluster from us?
An observer in Arp 220 would see the same Hubble Law that we do.
What is the cosmic microwave background? What are we looking at when we observe it?
Light emitted when the universe was full of hot opaque gas, that has been traveling through space since then.
The Fermi paradox stems from the fact that...
spacefaring and colonizing civilizations should cover the entire Milky Way rapidly compared to the age of the universe.
The Drake Equation expresses
the number of intelligent civilizations in the Milky Way
The value of the Hubble constant is about H0 = 20 km/sec/million light years.
The Perseus Cluster of galaxies is at a distance d = 200 million light years.
How fast is the Perseus Cluster moving away from us?
4,000 km/sec
If Dark Energy is a Cosmological Constant, what is the current best idea for the future history of our universe?
The Big Chill.
For what fraction of the history of the Universe has the Sun existed? Roughly ...
1/3
Constellations are ...
regions of the sky where we associate stars with one another.
What is the main cause of the seasons on Earth?
The tilt of the Earth's axis relative to its orbit about the Sun.
Which of these statements describes the position of the planets in the sky compared to the background stars?
Planets move in a complex way relative to the background stars, showing loops and back-and-forth motion.
The normal monthly phases of the Moon depend on ...
the Moon's position relative to the Sun as the Moon orbits the Earth.
About when was the telescope invented?
1600
Match the "players" in the Copernican revolution to one of their major contributions.
Copernicus - Proposed that the Earth goes around the Sun

Tycho Brahe - Obtained pre-telescopic observations that could distinguish between the Earth- and Sun- centered models.

Kepler - Constructed a mathematical model and a set of orbital laws that explain planetary motions around the Sun.

Galileo - First deployed the telescope for astronomy.
What causes stars to rise and set in the sky over the course of a night?
The rotation of the Earth on its axis.
Kepler's 2nd law of orbital motion ("equal areas in equal times") means that
Planets orbiting the Sun speed up in their orbits when they are closest to the Sun and slow down when they are furthest away.
The apparent change in the Sun's position in the sky relative to the background stars over the course of the year depends mainly on ...
The location of the Earth in its orbit around the Sun.
Which of these best describes the Earth's motion in space?
Every day the Earth spins once on its axis. Every year the Earth orbits the Sun once.
An ice skater (or figure skater) spins with their arms extended. Then they bring their arms in towards their body. What happens to their rate of spin (in revolutions per minute)?
The skater spins faster.
Compared to the gravitational force exerted by the Earth on the Sun, the gravitational force exerted by the Sun on the Earth is:
exactly equal.
Venus, the Earth and Jupiter are all on approximately circular orbits around the Sun. Rank their circular orbital velocities around the Sun from largest to smallest.
Venus, Earth, Jupiter
The Voyager satellite is moving at roughly 60,000 km/h away from the Sun. It ran out of fuel long ago.
It is far enough away from the Sun and other stars that the effect of gravity is small and we can say that Voyager is not being acted on by any gravitational force or any other force.
If you check back in on Voyager in 100,000 years what would you expect its speed to be?
About the same, 60,000 km/h.
Parallax is the apparent angular motion of relatively nearby stars compared to background stars over the course of a year on Earth, as our perspective on those nearby stars changes. Which of these statements is true about the parallax of nearby stars?
Stars that show a smaller parallax angle are farther away.
Which of these is the best description of parallax?
An observer shifts position and nearby objects appear to move relative to the background.
Consider two identical new planets found in the outskirts of our Solar System: planet "Brutus" and planet "Buckeye". Both planets have the same physical diameter in kilometers.
But, Planet Buckeye is two times farther from Earth than Planet Brutus. Planet Brutus has a smaller orbital semi-major axis than Planet Buckeye.
Which of the following statements is true about apparent angular size (diameter measured in degrees) of the two planets?
Planet Brutus appears two times larger than Planet Buckeye.
Planet Brutus appears two times larger than Planet Buckeye.
circle, center of mass
If the Earth vanished suddenly, and the force of gravity acting between the Earth and the Moon were shut off, what would happen to the Moon?
It would fly off in a straight line along its current direction of motion.
You are standing on the Oval at Ohio State facing due south, at the moment of sunset. The Moon rises just as the Sun sets. What phase is the Moon? What direction does it rise from?
Full Moon. East.
Of the eight planets in the Solar System, which has the fastest orbital velocity around the Sun? Which has the slowest?
Mercury. Neptune.
In the case of a planet-star system, which of these is always true?
Both the star and the planet orbit the common center of mass.
The rocky, terrestrial planets of the Solar System consist of
Mercury, Venus, Earth, Mars
Think about two space shuttles, OHIO and CLEVELAND. Both orbit the Earth in an approximately circular orbit. Space shuttle OHIO orbits at four times larger distance compared to space shuttle CLEVELAND (i.e., CLEVELAND is much closer to the Earth).
What can you say about their relative orbital speeds?
Hint: Look at the formula for orbital velocity in a circular orbit.
CLEVELAND has an orbital speed two times faster than OHIO.
A comet, say Halley's Comet, is on a very long, very elliptical and elongated orbit.
What can you say about the speed of the comet at various points in its orbit?
The speed is higher when the comet is close to the Sun.
In general, what is the shape of the orbits of planets or comets around the Sun?
Ellipses.
Earth has just gained a new moon!
This moon (named Brutus by popular vote) has exactly the same physical size as our current Moon.
Brutus is three times farther away from us than our current Moon.
What can you say about the apparent (or angular) size of Brutus compared to our current Moon?
The apparent size of Brutus is 1/3 that of the Moon.
Potassium-40 is a radioactive isotope that decays to Argon-40 with a half-life of about 1.25 billion years. If a sample of rock forms in the early solar system without any Argon-40, but with some Potassium-40, what happens?
The amount of Potassium-40 decreases, and the amount of Argon-40 increases, with about half of the Potassium converted into Argon in 1.25 billion years.
Evidence that our Solar System formed from a thin rotating disk of gas and dust comes from the fact that
all of the planets have orbital planes around the Sun that are very close to the ecliptic plane.
the spin of the Sun and the orbits of most of the Solar System bodies are in the same direction.
we observe disks of gas and dust around other stars.
About how old is the solar system? How do we know?
About 4.5 billion years. Radiometric dating of rocks.
From the reading, one set of ideas and theories for how the Solar System formed is called
the Nebular Hypothesis.
Which of these best describes the orbits of the planets and smaller Solar System bodies?
Most orbits lie the same plane and proceed in the same direction.
The planets in the Solar System orbit _____. This reflects that we think that they formed _____.
in roughly the same plane and direction; from a thin, spinning disk of gas and dust
Compared to the inner planets, the outer planets in the Solar System are _____ and _____.
more massive; made of more icy, gaseous material
We think that the differences in composition between the inner "terrestrial" and outer "jovian" planets reflects that ...
The outer planets formed where cold temperatures made ices available to help build planets.
T or F: The difference in the semi-major axis between Mercury's and Earth's orbit is about the same as the difference between Mars's and Neptune's.
False
What type of light does my dog glow in/does a human glow in? (i.e., what type of light does my dog give off)?
infrared light
On the FM dial, the frequencies run from 88 - 107 MHz (million cycles per second). On the AM dial, the range is 570 - 1600 kHz (thousand cycles per second). Which statements are true?
FM photons travel at the same speed as AM.
FM photons have shorter wavelengths than AM.
FM photons have higher energies than AM.
Gamma rays have higher energies than radio waves. Both are emitted by a nearby star at the same time. Which arrives first?
They arrive at the same time.
Through a telescope, Venus appears __________ when _________ and appears as a _________ when _________.
fullest, furthest away; crescent, closest to Earth
Ultra-violet photons have higher energies than microwave photons. Both types of photons are emitted by a nearby star at precisely the same time. Which arrives first?
They arrive at the same time.
Two planets, NEARPLANET and FARPLANET, orbit the same star on near-circular orbits. The orbit of FARPLANET has an orbital semi-major axis three times larger than that of NEARPLANET. What can you say about the orbits of the two planets?
FARPLANET has a slower orbital speed, and a longer orbital period than NEARPLANET.
You observe some infrared light and some visible light.
The visible light has a 10 times higher frequency than the infrared light.
How do the wavelengths of the infrared and visible light that you observed compare?
The wavelength of the infrared light is 10 times larger than that of the visible light.
How can light from stars most directly tell us about their composition?
Sharp features (dark or light bands) in the spectrum reflect the unique quantum mechanical structure of the atoms that makes up the object.
If you measure the orbital period of a binary star system (two stars in an orbit around each other) and the semi-major axis of the orbit, what property of the system can you calculate from Newton's generalization of Kepler's 3rd Law?
The total mass of the whole system (both stars).
If you know the distance to an object and you measure its apparent brightness you can figure out:
the luminosity of the object.
Oxygen-Neon-Magnesium white dwarfs are the remnants of intermediate mass (4-8 times the Sun's mass) stellar evolution
True
Stars on the main sequence are in thermal equilibrium.
True
Carbon-Oxygen white dwarfs are the remnants of low mass (stars less than 4 times the mass of the Sun) stellar evolution.
True
The Sun is a star!
True
Stars on the main sequence are powered by the fusion of Hydrogen into Helium.
True
White dwarf stars and neutron stars shine only by residual heat.
True
Neutron stars and black holes are the product of high mass (>8 times the mass of the Sun) stellar evolution.
True
Helium fusion is less efficient than Hydrogen fusion. This is why the duration of the red clump/horizontal branch phase of stellar evolution is shorter than the main sequence phase.
True
Low mass stars (< 4 times the mass of the Sun) do not undergo fusion of Carbon and Oxygen.
True
Stars on the main sequence are in hydrostatic equilibrium.
True
We know the age of the Solar System and Earth quite precisely. How?
Radioactive dating of rocks provides very precise estimates.
A Main Sequence star that is about 10 times more massive than the Sun is about 10,000 times more luminous. Its Main Sequence lifetime is therefore approximately
1,000 times shorter than the Sun's.
Saturn is about 10 times the size of Venus (i.e., it has 10 times the diameter of Venus). When both planets are at closest approach to the Earth, Saturn is about 30 times farther away from the Earth than Venus. How does the angular size or apparent size (i.e., the angular diameter) of Saturn at closest approach compare to that of Venus at closest approach?
Venus has an apparent size 3 times bigger than Saturn.
Saturn's semi-major axis is about 10 astronomical units from the Sun. Compare the apparent brightness of the Sun from Earth to the apparent brightness of the Sun from Saturn.
The Sun appears 100 times fainter at Saturn than at Earth.
Near-infrared light has a wavelength 3 times longer than that of red light. How do the frequency of near-infrared light and red light compare?
Red light has a frequency 3 times larger than that of near-infrared light.
On the HR diagram, three stars all have the same temperature (color index), but different luminosities. Order the three stars in order of INCREASING size, from physically smallest to physically largest.
white dwarf, main sequence blue star, blue supergiant.
Object A has a mass of 10 kg. Object B has a mass of 1000 kg. If the same force is applied to both...
A will accelerate 100 times more than B.
You measure the parallax of two stars (i.e., you measure their angular shift between June and December as the Earth goes around its orbit). Star SCARLET shows a parallax angle that is two times bigger than Star GRAY. What can you say about the two
Star GRAY is two time farther away than star SCARLET.
The speed of light is 300,000 km/s . The distance from the Earth to Mars at closest approach is about 50,000,000 km. How much time does it in seconds take a radio signal sent from a rover on Mars to reach Earth?
About 200 seconds
There are about 200 billion stars in the Milky Way Galaxy. It is estimated that roughly 1 out of every 100 stars formed will explode (as a supernova) shortly after it forms. How many total stars have exploded in the Milky Way over the course of its history?
2x10^9
Galileo's observations of the Sun strongly indicated that
It rotates
Venus is in a very nearly circular orbit about the Sun. We measure the size of its orbit (about 0.7 AU) and its orbital speed (about 35 km/s). What other piece of information could we figure out from these quantities? (Hint: Think about your Galileo moons of Jupiter lab.)
The mass of the Sun
Mars is in a nearly circular orbit about the Sun. We measure the semi-major axis of its orbit (about 1.5 AU) and its orbital speed (about 25 km/s). What other piece of information could we figure out from these quantities? (Hint: Think about your Galileo moons of Jupiter lab.)
The mass of the sun.
About how high is University Hall?
100 feet
Two objects separated by a distance d are pulled apart to a distance of 10d. How has their gravitational force changed?
Decreased by a factor of 100.
Two stars, A and B, have the same intrinsic luminosity, but star B is two times further away than star A. Which star is brighter and by how much?
Star A is 4 times brighter than star B.
Two stars are at the same distance and have the same temperature, but they have different radii. The larger star will be...
Brighter.
Rank the frequencies of the following types of light from 1 (lowest) to 4 (highest):
red, green, blue, x-rays.
What part of the electrogmagnetic spectrum does the Sun's spectrum peak in?
Visible.
An object in orbit experiences acceleration _____ caused by _____.
Towards the other body in the orbit; gravity
Over the course of an orbit of each planet around the Sun, space stations on Mercury, Earth, and Jupiter measure the parallax angle of a nearby star. Which measures the LARGEST parallax angle?
Jupiter
The ideal gas law states that the pressure of a gas
Increases as density or temperature increase.
Jupiter's semi-major axis is 5 astronomical units. How does the apparent brightness of the Sun from the orbit of Jupiter compare to the apparent brightness of the Sun from the orbit of Earth?
The sun appears 25 times fainter from the orbit of Jupiter than from the orbit of Earth.
In following the Main Sequence on the H-R diagram in the direction of increasing MASS (from low mass stars to high mass stars), one is also following a sequence of...
Increasing temperature.
Hydrogen gas emits radiation with a wavelength of 21 cm in your laboratory on Earth. You observe the same Hydrogen spectral feature in a distant star's spectrum at 26 cm. From this, you can conclude that the star...
Is moving away from Earth at high velocity.
Which of the following was a empirical argument used by Aristotle for why the Earth is a sphere?
Constellations that were low in the sky when viewed from northern latitudes were higher in the sky when viewed from more southern latitudes.

The Moon shows phases indicating it is a sphere.

During a lunar eclipse, the shadow cast by the Earth on the Moon is a circle.
At the moment of sunrise, you are facing due south, standing in the middle of the Oval at Ohio State. The Moon is directly south, and half illuminated. Is the Moon waxing or waning? If you went to that spot, at sunrise on the next day, would the Moon have moved to the east or west of where it was the previous day?
Waning; east
Galileo showed that massive bodies in the gravitational field of Earth fall with...
Constant acceleration, independent of mass
If you moved the Earth three times further away from the Sun than it is now (that is, you increased the semi-major axis of the Earth's orbit from 1AU to 3AU), what would happen to the force of gravity between the Earth and the Sun?
The force of gravity would decrease by a factor of 9.
If an object is moving in a circular orbit and you speed it up, giving it a bit more speed (but not enough to escape) what will its new orbit look like?
An ellipse with a bigger long ("semi-major") axis than the current orbit.
Three stars are on the HR diagram. All three stars have the same temperature (color index). Star X has the lowest luminosity. Star Q has the highest luminosity. Star D is in between Star X and star Q, with intermediate luminosity. List the stars in order of INCREASING physical radius FROM SMALLEST TO LARGEST.
X, D, Q
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chemistry
The thermal decomposition of phosphine $\left(\mathrm{PH}_3\right)$ into phosphorus and molecular hydrogen is a first-order reaction: $$ 4 \mathrm{PH}_3(\mathrm{~g}) \longrightarrow \mathrm{P}_4(\mathrm{~g})+6 \mathrm{H}_2(\mathrm{~g}) $$ the time required for 95 percent of the phosphine to decompose..
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computer science
Write your own version of a class template that will create a static queue of any data type. Demonstrate the class with a driver program.
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engineering
Use the method outlined as discussed previously to solve the following Bernoulli equations. a. $y^{\prime}(t)+y=2 y^2$ b. $y^{\prime}(t)-2 y=3 y^{-1}$ c. $y^{\prime}(t)+y=\sqrt{y}$
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anatomy
When blood glucose concentrations are elevated, the glucose molecules are a) catabolized for energy. b) used to build protein. c) used for tissue repair. d) all of these.
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