Term
| Astronomers use different types of telescope designs to observe light from different portions of the electromagnetic spectrum because... |
|
Definition
| light at different wavelengths interacts differently with matter, so we have to use different materials and methods for collecting short and long wavelengths. |
|
|
Term
| We can see through a glass window because it |
|
Definition
|
|
Term
| Without telescopes or other aids, we an look up and see the Moon in the night sky because |
|
Definition
| It reflects visible light |
|
|
Term
| How does increasing the wavelength affect the energy and speed of a photon (a particle of light)? |
|
Definition
| Longer wavelength means lower energy, but the speed is unaffected. |
|
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Term
| If you wanted to learn about an object's chemical composition, what would be the most useful? |
|
Definition
| The object's absorption line spectrum |
|
|
Term
| A dense object gives off... |
|
Definition
|
|
Term
| A hot, low-density cloud of gas gives off... |
|
Definition
|
|
Term
| What is temperature a measure of? |
|
Definition
| The average kinteic energy of a group of particles. |
|
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Term
| When a person falls off the edge of a cliff, the reason they fall is because... |
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Definition
| the gravitational force of the Earth on the person is equal and opposite to the person's force on the Earth. The person's mass is so much smaller than the Earth's, they end up with a large acceleration while the Earth's acceleration is too small to be noticed |
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Term
| If you are standing in Kalamazoo, which is 40o N latitude, where in your sky could you see Polaris, the North star? |
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Definition
| Due North at an altitude of 40o above the horizon |
|
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Term
| What is meant by a constellation? |
|
Definition
| A region of the sky with well defined borders |
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Term
| The star Rigel is about 770 light years away from Earth. If Rigel were to explode in a supernova today, when could we know about it? |
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Definition
|
|
Term
| Using the Cosmic calendar, where the entire age of the universe is compressed into one year, roughly when did dinosaursgo extinct? |
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Definition
|
|
Term
| Roughly how many galazies are there in the obsevable universe? |
|
Definition
|
|
Term
| A light year is approximately... |
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Definition
|
|
Term
Which is the largest?
-a light year
-diameter of a typical galaxy
-distance to Pluto
-distance to the nearest star
-diameter of the sun |
|
Definition
| diameter of a typical galaxy |
|
|
Term
| Using the Cosmic Calendar, where the entire age of the universe is compressed into one year, when did our galaxy form? |
|
Definition
|
|
Term
| Resolving power is the ability to... |
|
Definition
| reveal fine detail in an image |
|
|
Term
| Why do we put telescopes in space? |
|
Definition
| to reduce the effects of light pollution, to eliminate turbulence from the atmosphere, to avoid absorption of certain portions of the light spectrum by the atmosphere |
|
|
Term
| If you want to improve the angular resolution of a telescope, the best way to do so is to... |
|
Definition
| increase the diameter of the opening of telescope |
|
|
Term
| From lowest energy to highest energy, what is the correct order of electromagnetic radiation? |
|
Definition
| radio, infrared, visible light, ultraviolet, X rays, gamma rays |
|
|
Term
| as a planet in an elliptical orbit around the sun gets closer to the sun it goes... |
|
Definition
| faster because it gains kinetic energy as it loses gravitational potential energy |
|
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Term
| when an ice skater is spinning and pulls in her arms, she spins: |
|
Definition
| faster because of conservation of angular momentum |
|
|
Term
| as a planet in an elliptical orbit around the sun gets gloser to the sun it goes... |
|
Definition
| faster because it gains kinetic energy as it loses gravitational potential energy |
|
|
Term
| What are the hallmarks of science? |
|
Definition
-explanations must be based solely on natural causes and can not rely on divine intervention
-given two competing tested models that explain a natural phenomena, the simplest explanation is preferable
-a scientific model must make testable predictions which would force us to abandon or revise the theory if they are proved to be wrong |
|
|
Term
| What is a circumpolar star? |
|
Definition
| a star that is always above your horizon |
|
|
Term
| when you are standing in Kalamazoo, what is the point that is directly over your head? |
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Definition
|
|
Term
The celestial sphere is another name for our universe.
True or False? |
|
Definition
|
|
Term
| Using the Greek naming system, what would you call the second brightest star in the constellation Orion? |
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Definition
|
|
Term
| Why do stars look like they rise in the east and set in the west? |
|
Definition
| Because the Earth is rotating on its axis |
|
|
Term
|
Definition
| the plane of the Earth's orbit around the Sun |
|
|
Term
| What makes the North Star, Polaris, special in our night sky? |
|
Definition
| It does not move much during a night since it is very close to the North Celestial Pole. |
|
|
Term
| Elements heavier than H and He that we find on Earth, for example Silicon and Calcium, were... |
|
Definition
| created by nuclear fusion in the cores of an earlier generation of stars |
|
|
Term
| What was the first evidence astronomers discovered that led to the Big Bang Theory? |
|
Definition
| All galaxies outside the Local Group are moving away from us, and the farther away they are, the faster they're going |
|
|
Term
| How big is the Milky Way Galaxy? |
|
Definition
| It is roughly 100,000 light years in diameter and contains about 100 billion stars |
|
|
Term
|
Definition
|
|
Term
| If the Earth were the size of a basketball, the moon would be roughly the size of... |
|
Definition
|
|
Term
| How far is it to the nearest star, other than our Sun? |
|
Definition
|
|
Term
| The average distance from the Earth to the Sun is... |
|
Definition
|
|
Term
| When we say a spectrum is red shifted, it means the object |
|
Definition
|
|
Term
| If the temperature of a star increases from 2,000 K to 8,000 K the power it radiates |
|
Definition
| increases a factor of 256 |
|
|
Term
| How would you describe the law of conservation of energy? |
|
Definition
| the total quantity of energy in the universe never changes |
|
|
Term
| If the distance between two planets is decreased by a factor of 4, the gravitational force between them.... |
|
Definition
|
|
Term
|
Definition
| An explanation for a wide variety of observations that has been repeatedly tested, has a wide body of evidence that supports it, and has not failed any crucial test. |
|
|
Term
| The force of gravity is an inverse square law. What does this mean? |
|
Definition
| If you triple the distance between two large masses, the gravitational force between them decreases by a factor of 9. |
|
|
Term
| How many degrees are in a full circle? |
|
Definition
|
|
Term
| What do we mean by "observable universe"? |
|
Definition
| Refers to the portion of the universe that we can see in principle, given the current age of the universe. |
|
|
Term
| What happens when the gravity of a massive star is able to overcome neutron degeneracy pressure? |
|
Definition
| The core contracts and becomes a black hole |
|
|
Term
For a white dwarf to become a nova, it is necessary for it to have a companion star.
True or False? |
|
Definition
|
|
Term
| How do we know that pulsars are neutron stars? |
|
Definition
| No massive object, other than a neutron star, could spin as fast as we observe pulsars spin. |
|
|
Term
| You are more likely to survive passing through the event horizon of a very massive black hole than a less massive black hole. |
|
Definition
|
|
Term
| What determines how strong the tidal forces on an object are? |
|
Definition
| The differences in how strong the gravitational force is on the nearest and fartherst parts. |
|
|
Term
| What evidence shows that black holes exist? |
|
Definition
| In binary systems that show a star with an invisible massive companion; in the cores of galaxies based on the motion of stars near the core. |
|
|
Term
| What explains why neutron stars spin rapidly? |
|
Definition
| Because conservation of angular momentum means the rate of spin will increase as a star collapses to form a neutron star. |
|
|
Term
| What determines how strong the tidal forces on an object are? |
|
Definition
| the differences in how strong the graviational force is on the nearest and farthest parts. |
|
|
Term
| Why do heavier elements require higher temperatures to fuse? |
|
Definition
| they have more positively charged protons in their nuclei, so have to be moving faster to approach close enough for the nuclear strong force to fuse them. |
|
|
Term
| What would you see if you were to observe astronaut Susan's fall into a relatively low mass black hole? |
|
Definition
-Susan's clock would start to run slower than yours
-the light from her spaceship would become red shifted
-she would be ripped about by tidal forces as she approaches the event horizon |
|
|
Term
| Why is there an upper limit to the mass of the white dwarf? |
|
Definition
| the more massive the white dwarf, the greater the degeneracy pressure and the faster the speeds of its electrons. Near 1.4 solar masses, the speeds of the electrons approach the speed of light, so more mass cannot be added without breaking the degeneracy pressure. |
|
|
Term
If the Sun were magically replaced by a one solar mass black hole, we would still continue to orbit in a period of one year.
True or False? |
|
Definition
|
|
Term
In a white dwarf, we have packed the mass of the Sun into the volume of Earth.
True or False? |
|
Definition
|
|
Term
When a brown dwarf cools, the degeneracy pressure drops and the brown dwarf gets smaller.
True or False? |
|
Definition
|
|
Term
When does a massive star reach the point when it is about to go super nova?
|
|
Definition
| When the mass of its iron core reaches the point where electron degeneracy pressure can no longer sustain it. |
|
|
Term
| Why are star clusters ideal "laboratories" for stellar evolution? |
|
Definition
| Their stars all formed at about the same time and are roughly the same distance from Earth. |
|
|
Term
The temperature needed to sustain H He fusion is approximately 10 million K.
True or False? |
|
Definition
|
|
Term
| How do we know what goes on under the surface of the Sun? |
|
Definition
| By a combination of helioseismology, neutrino detection, and mathematical models. |
|
|
Term
| In which portion of the sun is energy transported outward primarily through light in the visible range? |
|
Definition
|
|
Term
The most common element in the Sun is hydrogen.
True or False? |
|
Definition
|
|
Term
The mass of a neutrino is 30% of the mass of an electron.
True or False? |
|
Definition
|
|
Term
| As the sun spends more time on the main sequence, how do you expect its chemical composition to change? |
|
Definition
| It should have a higher concentration of iron Fe |
|
|
Term
| In a nuclear reaction, where does the energy come from? |
|
Definition
| A small amount of mass is turned into energy |
|
|
Term
| Given two identical stars A and B, if Star A is closer to us than Star B, how do their parallax angles compare? |
|
Definition
| Star A's parallax angle is larger than that of Star B. |
|
|
Term
Open and globular clusters each typically contain a few hundred stars.
True or False? |
|
Definition
|
|
Term
| What is the spectral sequence in order of decreasing temperature? |
|
Definition
|
|
Term
| How long does it take energy generated in the core of the sun to escape into space? |
|
Definition
| Hundreds of thousands of years |
|
|
Term
| Our Sun is classified as... |
|
Definition
|
|
Term
| Why are high pressures required to sustain nuclear reactions? |
|
Definition
| Because they increase the number of atoms in the core, making collisions between the nuclei occur more often |
|
|
Term
| What would happen inside the Sun if a slight rise in core temperature led to a rapid rise in fusion energy? |
|
Definition
| It would cause the core to expand and thereby cool. |
|
|
Term
|
Definition
|
|
Term
An O star has the longest life as a main-sequence star.
True or False?
|
|
Definition
|
|
Term
M is one of the spectral types that is the coldest.
True or False? |
|
Definition
|
|
Term
| Cluster ages can be determined from... |
|
Definition
|
|
Term
| How do we determine the mass of distant stars? |
|
Definition
| From their period and orbital speed in binary star systems. |
|
|
Term
| The temperature of Star A is twice the temperature of Star B, but its radius is only half as big as Star B's. Which star is more luminous? |
|
Definition
|
|
Term
| How would you correctly describe the stages of life for a low-mass star? |
|
Definition
| protostar, main-sequence, red giant, white dwarf |
|
|
Term
| If we do a survey of all the starswe can observe with the Hubble Space telescope, what would we find? |
|
Definition
| A greater number of red stars than blue stars. |
|
|
Term
| When does a star turn into red giant? |
|
Definition
| After it uses up all of the H in the core. |
|
|
Term
|
Definition
| Because they have heat from the gravitational contraction of the cloud. |
|
|
Term
| What do we mean when we refer to "stellar temperature"? |
|
Definition
|
|
Term
| When a star becomes a red giant, why does it become much brighter? |
|
Definition
| because it is getting larger. |
|
|
Term
| You measure that Procyon has a stellar parallax of 0.05 arcseconds. How far away is Procyon? |
|
Definition
| 20 parsecs, or 65.2 light years. |
|
|
Term
|
Definition
| A massive particle that only interacts via the weak force and gravity. |
|
|
Term
| What might be causing the expansion of the universe to accelerate? |
|
Definition
|
|
Term
| What evidence do we have that dark matter exists? |
|
Definition
-orbital speedsin galaxies is too high to be held in place by the gravity from the luminous matter
-the speeds of galaxies in galactic clusters is too high to account for by the gravity from the luminous matter
-the temperature of hot gas in galactic clusters is too high to be bound by the gravity from luminous matter
-gravitational lensing |
|
|
Term
| Why do we expect that WIMPs should be distributed throughout galactic halos, rather than settled into a disk? |
|
Definition
| Since they do not interact via the electromagnetic force, they could not emit radiation to settle into the disk like ordinary matter could. |
|
|
Term
When we say that a cluster of galaxies is acting as a gravitational lens, what do we mean?
|
|
Definition
| It bends or distorts the light coming from galaxies located behind it. |
|
|
Term
| What do we mean by MACHOs? |
|
Definition
| Particles with mass that have condensed into a compact form and are found in the halo of the galaxy |
|
|
Term
| What are the two key observational facts that led to widespread acceptance of the Big Bang model? |
|
Definition
| the cosmic background radiation and the helium content of the universe |
|
|
Term
| How far back can we see light from after the Big Bang and why? |
|
Definition
| 380,000 years after the Big Bang, because that is when electrons became bound to the nuclei and photons were free to travel without scattering. |
|
|
Term
| What are the largest scale structures in the universe? |
|
Definition
| chains, sheets, and walls of galaxies that surround voids |
|
|
Term
| Why isn't space expanding within systems such as our solar system or the Milky Way? |
|
Definition
| Their gravity is strong enough to hold them together against the expansion of the universe. |
|
|
Term
| What kinds of objects lie in the halo of the Milky Way galaxy? |
|
Definition
|
|
Term
| When we plot the velocity of stellar orbits as a function of distance from the center of the Milky Way galaxy, what do we find? |
|
Definition
| As we go farther out, the velocity remains relatively flat. |
|
|
Term
| Stars in the halo of the Milky Way Galaxy tend to be.. |
|
Definition
-in globular clusters
-red and yellow
-older
-poor in heavy elements |
|
|
Term
| What evidence supports the existence of a black hole at the center of our galaxy? |
|
Definition
| The motions of the gas and stars at the center indicate that it contains 4 million solar masses within a region only 3 light-years across |
|
|
Term
| Where in our galaxy are we most likely to find stars that have Earth-like planets? |
|
Definition
|
|
Term
| Of the various types of gas found between the stars, within which type do stars form? |
|
Definition
| T=10 K, molecular clouds, density=104 particles/cm3 |
|
|
Term
| Which are the regions of most active star formation in the milky way galaxy? |
|
Definition
|
|
Term
| what do we observe in a region of space that indicates that star formatin is occuring? |
|
Definition
| High mass blue stars and inonization nebula |
|
|
Term
| Which model of the universe gives the oldest age for its present size? |
|
Definition
|
|
Term
| Helium originates from what? |
|
Definition
| mostly from the Big Bang with a small contribution from stella nucleosynthesis. |
|
|
Term
| If astronomers had discovered that the cosmic microwavebackground was precisely the same everywhere, instead of having very slight variations in temperature, then we would have no way to account for... |
|
Definition
| how galaxies came to exist |
|
|
Term
| In stars, helium can sometimes be fused into carbon and heavier elements. Why didn't the same fusion processes produce carbon and heavier elements in the early universe? |
|
Definition
| By the time stable helium nuclei had formed, the temperature and density had already dropped too low for helium fusion to occur. |
|
|
Term
The cosmic background radiation is expected to contain redshifted emission lines from hydrogen and helium, and it does.
True or False? |
|
Definition
|
|
Term
| Which of the four fundamental forces is the weakest? |
|
Definition
|
|
Term
| What would be the most appropriate method to determine the distance of stars that are about 10 light years away? |
|
Definition
|
|
Term
| What evidence do we have for a super massive black hole at the center of our Milky Way Galaxy? |
|
Definition
| The stars near the center are orbiting with such high speeds that indicate an object of roughly 3 million solar masses which is less than one light year across. |
|
|
Term
| Which of the following make good standard candle and why? |
|
Definition
| White dwarf supernova, because white dwarfs all have a critical mass of 1.4 Msolar |
|
|
Term
| What would be the most appropriate method to determine the distance of stars in nearby galaxies? |
|
Definition
|
|
Term
| how does the interstellar medium obscure our view of most of the galaxy? |
|
Definition
| It absorbs or scatters visible, ultraviolet, and some infrared light. |
|
|
Term
| What portion of the spectrum would reveal where cosmic rays from supernova explosions collide with atomic nuclei in gas clouds? |
|
Definition
|
|
Term
| What role do galaxies play in making life (as we know it on Earth) possible? |
|
Definition
| they allow the heavy element enriched gas from dying stars to be recycled in new star systems |
|
|
Term
| An isolated proto-galactic cloud with large net angular momentum is likely to form as which basic type of galaxy? |
|
Definition
|
|
Term
| In the "tuning fork" diagram of Hubble's classification of galaxies, which corresponds to the most spherical in shape? |
|
Definition
|
|
Term
| How does the estimated age of the universe depend on Hubble's constant? |
|
Definition
| the larger H0, the younger of the universe |
|
|
Term
If Hubble's constant is Ho = 22 km/s/million light years and you measure the redshift of a galaxy and determine it's velocity is 550 km/s, what distance was the galaxy at?
|
|
Definition
|
|
Term
| How lumionous is a Cephid with a period of 30 days? |
|
Definition
|
|
Term
| In the "tuning fork" diagram of Hubble's classification of galaxies, which corresponds to a barred spiral? |
|
Definition
|
|
Term
| A very dense proto-galactic cloud is most likely to end up as... |
|
Definition
| an elliptical galaxy, because it would form stars before the matter had time to settle into a disk. |
|
|
Term
Comared to spiral galaxies, elliptical galaxies are redder and rounder.
True or False? |
|
Definition
|
|
Term
| What would be the most appropriate method to determine the distance to the most distant observable galaxies? |
|
Definition
|
|
Term
Of the critical density of the universe, roughly 4% is ordinary matter, 25% is dark matter, and 71% is dark energy.
True or False? |
|
Definition
|
|
Term
| What do we mean by the critical density of the universe assuming no dark energy were present? |
|
Definition
| The average density the universe would need in order for gravity to balance out the expansion |
|
|
Term
| Although the most astronomers assume dark matter really exists, there is at least one other possible explanation for the phenomena attributed to dark. What is it? |
|
Definition
| There could be something wrong or incomplete with our understanding of how gravity operates on galaxy-size scales. |
|
|
Term
| Why do we call dark matter "dark"? |
|
Definition
| It emits no or very little radiation of any wavelength |
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|
