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69 Cards in this Set
- Front
- Back
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One of the reasons Pluto was designated not to be a planet...
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it has not cleared the debris out of its orbital neighborhood
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The debris left over from these objects can cause meteor showers
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Comets
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These SS objects typically have very elongated, eccentric orbits with large avg. distances to the sun
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COMETS
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When a star's visible light passes through cold interstellar dust on its way to us, we see
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the light DIMMED and REDDENED in color
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Looking toward the Milky Way, some regions appear dark because...
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The stars are obscured by interstellar dust
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In 1883, he was the first to successfully measure parallax of a star.
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Freidrich BESSEL
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A TRUE STATEMENT
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Reflection nebulae and the sky are blue for the same reason: dust scatters blue light more efficiently
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This type of galaxy exhibits orderly rotation of stars about its galactic center as well as significant gas
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SPIRAL GALAXY
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Galaxy A is moving away from the Milky Way
(MW) at a speed of 10,000 km/s. Galaxy B is receding from the MW at a speed of 40,000 km/s. What can be said about their distances? |
Galaxy A is 4 times closer than Galaxy B
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The stars in the MW galaxy often appear redder in color than the stars in nearby galaxies. This was noted by SHAPLEY and can occur because...
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the light from the stars in the milky way passes through a lot of dust, so the stars become dimmed and reddened
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He classified galaxies into a small number of basic types
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HUBBLE
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The precession of the perihelion of Mercury...
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is not predicted by Newtonian Gravity, but is corrected accounted for by General Relativity
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The speed of light is 300 Million Meters per
second. If a spaceship travels toward me at 100 Million Meters Per second and emits a light, at what speed do I perceive the light to be traveling? |
300 million meters/second
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I observe two events (two explosions for example) to occur at precisely the same time. According the the Special Theory of Relativity...
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Observers moving with respect to these events may not think that they are simultaneous.
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The typical distances to larger galaxies that are similar to the MW would be....
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A few MILLION light years
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Evidence for the exchange of energy in discrete chunks, part of the theory of quantum mechanics, comes from
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The photoelecric effect of Einstein
the energy level in hydrogen atoms (Bohr) thermal radiation in warm objects (PLank) |
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Protons and neutrons in an atom are held together by...
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STRONG NUCLEAR FORCE
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Suppose H0
=75 (km/s)/Mpc and we observed a galaxy receding from the Milky Way at a speed of 7500 km/s. Roughly how far away is that galaxy? |
100mpc
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Suppose that the universe were not expanding or contracting. What should we expect of the velocity of galaxies?
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Speeds should be random, with some approaching us and some receding
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Einstein's theory has surpassed Newton's Theory as the most acceptable theory of gravity. WHY?
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Einstein's theory is more accurate, but Newton's is useful in many ways
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Einstein introduced the cosmological term to his theory of General Relativity to...
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Support his belief in a Steady State Universe, or rather, a static universe
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The center of the universe is...
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not though to be useful concept in current theorise
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The patterns of fluctuations in the CMB indicates ....
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we live in a FLAT universe
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Some early evidence for "dark matter" came from
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Fritz Zwicky and his observations of the Coma Cluster
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The universe will eventually stop expanding and recollapse if...
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The density of its matter exceeds the critical density
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Our galaxy and our solar system does not expand as the universe does because ....
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the density within a galaxy is much higher than average and this overcomes the expansion
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The stars in the plane of the disk of the Milky Way often appear redder in color to observers on Earth than they
intrinsically are. This effect is ... |
It is called reddening and due to the dust between Earth and stars being observed
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You see an astronomy magazine with a brilliant, blue, cloud-like nebula on the cover. You explain to your
friend that the object on the cover is ... |
a reflection nebulae that is glowing blue because the light of newly formed stars in the nebula is more efficiently reflected by interstellar dust
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When we observe stars near the center of our galaxy, we observe light that was emitted from those stars ...
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about 27,000 years ago
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An observer far outside the MW galaxy would best describe our Galaxy and the Sun's position as...
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A disk of stars, with our SS closer to the outer edge
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He was the first to measure the effect of stellar parallax
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FRIEDRICH BESSEL
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Proposed that the milky way was a flattened disk of stars and that Spiral nebulae were "island universes" similar to the milky way
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IMMANUEL KANT
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Thomas' Wright picture of the MW was that of...
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A spherical shell of stars
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He discovered Uranus
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Herschel
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Bessel’s first successful measurement of stellar parallax was important for many reasons and connects back to
Ancient and Renaissance Astronomers because .... |
measurement of stellar parallax is one proof that the Earth moves about the Sun that was not
measurable previously. |
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Jacobus Kapteyn...
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Was the first to use star counts to develop a detailed model with the sun at the center of a distribution of disklike stars
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Harlow Shapley...
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used the position of GLOBULAR CLUSTERS to deduce that the sun does not lie near the center of the MW
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Former director of ALL. OBSERVATORY
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CURTIS
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The valid point of SHAPLEY in the Great Debate was...
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the spiral nebulae usually appear bluer in color than the MW does
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The valid point raised by CURTIS in the Great Debate was...
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bright novae are often seen in Andromeda, so there must be many stars in Andromeda
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The position of the Sun in the MW is best described as...
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in the disk, slightly more than halfway from its center
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Henrietta Leavitt
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showed that Cepheid variable stars follow a distinct relationship between dimming and brightening period, and peak luminosity
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Spiral galaxies outside of the Milky Way generally appear bluer than one could conclude by looking through
the Milky Way because.. |
The effect of reddening makes thing in the disk of MW appear redder to us than they would otherwise appear
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Ed Hubble
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Resolved the great debate by measuring the distances to external galaxies and resolving individual stars in Andromeda Galaxy
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VESTO SLIPHER
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measured the spectra of external galaxies nothing that they were nearly always redshifted
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An effective way to measure the distance of distant galaxies is to look for objects within those galaxies which we know the...
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LUMINOSITY
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CORRECT STATEMENT
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Newton described galaxy as a force that acts instantaneously between objects with mass, while Einstein's gravity is a curvature of space time due to mass and energy
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According to SPECIAL relativity
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time and space are inseparably linked and observers have a perspective of spacetime that is determined by relative motion
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Einstein recognized that the Special THeory of Relativity was in conflict with Newton's Theory of Gravity Because...
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Newton's predicts that gravitational forces can change instantaneously over vast distances, whereas Relativity restricts all signals to travel at speeds less to or equal to the speed of light
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Among Einstein's many accomplishments he...
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explained the Photo-electric effect
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The Soloar Eclipse of 1919 was used to test
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The GENERAL theory of relativity
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Einstein's theories of relativity emphasize the following points that make the center of the SS a mute point
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There is NO WAY to define absolute motion. Meaning there is no way to definitively determine who is moving, and who is stationary
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The strange precession of Mercury's orbit...
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was not predicted by Newton's Theory of Gravity, but is predicted by the General Theory of Relativity
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A simple theory of atomic structure based on the ideas of Quantum mechanics that explains the energy levels of atoms was formulated by
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NEILS BOHR
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Of the four fundamental forces in Nature, the one that allows a proton to be converted into a neutron or vice versa is...
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WEAK nuclear force
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Which of the following elements or isotopes are not made in the universe?
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CARBON
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A universe that is finite in volume will exhibit the geometrical rules of an
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CLOSED UNIVERSE in which the interior angles may sum up to more than 180
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Edwin Hubble...
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Discovered the expansion of the universe
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A Russian Immigrant, he first developed the idea that nuclei could be synthesized during the early stages of the expansion of the universe and that prediction could be used to test the Big Bang Theory
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GEORGE GAMOW
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The Discovery of the CMBR...
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falsified the Steady State Theory, but was consistent with BBT
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CMB is visible in every direction because
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We are looking back to a time when the universe was young and hot no matter what direction we look
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Besides CMB, what is also considered as strong evidence for the BBT...
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the fraction of Helium and other light elements and isotopes such as Lithium
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The steady state theory of Cosmology states that the universe is expanding but new matter is created so that the appearance of the universe never changes. This theory implies that...
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There are other galaxies in the universe significantly older than the Milky Way
There was no hot, dense phase of Universe The space density of galaxies should be the same at all times Helium must be created in the same proportion of hydrogen as new things are being created |
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We know that the sky is relatively dark because...
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The universe has a finite age
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Fluctuations in the intensity of the CMB indicates
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That the universe is Flat
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Scientists have determined the geometrical shape of universe using
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Measurement of the sizes and the intensity of fluctuations in the CMB
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Which is the correct ranking of constituents in the Universe ranking from most abundant to least?
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Dark energy, Dark matter, luminosity
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Fritz Zwicky...
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Measured the speeds of galaxies in the Coma Cluster to deduce the existence of dark matter
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The dark energy problem of today is related to Einstein's cosmological term because...
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dark energy resists gravity similar to the cosmo constant
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