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EXPLORING THE UNIVERSE
FINAL EXAM
66
Science
Undergraduate 3
12/08/2011

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Term
What is the zodiac
Definition
Belt shapes region of the sky surrounding the ecliptic passes through twelve constellations
Term
what is the ecliptic
Definition
Line we see that runs around the celestial sphere, traced by the sun as it moves through the constellations.
Term
Newtons law of gravity
Definition
F=GMm/d^2
Term
Difference between mass and weight
Definition
Mass is how much space an object takes
Weight is how much gravity an object is pulling down on that object
Term
What causes the interior of the Earth to be hot?
Definition
Four reasons:
1)Remnants from the impact when the earth was forming
2)Earth was hot and the heavy elements sunk to the core, takes longer too cool
3)Compression due to gravity
4)Decay of radioactive elemnts
Term
The area off the coast of Japan is
Definition
the ring of fire, major earthquake area, subduction zone
Term
Plate motion along the San Andreas fault
Definition
Land west of the fault moves northwest while the east moves southwest. They grind against each other.
Term
Reason why the idea of continental drift was rejected
Definition
1) it had been shown that floating masses would collect at the equator and stay there
2) masses floating freely in a fluid substratum like icebergs in the ocean should be in isostatic equilibrium, and its not .
3) problem of why some parts of the earths surface should have solidified while other parts were still fluid.
Term
Formation process and cause of smoothness of lunar maria
Definition
Volcano rose to the surface causing the smoothness of the maria
Term
Effect of the ocean tides on the Earth's rotation
Definition
Tides create forces that slow the earths rotation and move the moon farther away-tidal braking
Term
Principal cycles of the Moon's orbit
Definition
New, waxing crescent, first quarter, waxing gibbous, full, waning gibbous, third quarter, waning crescent, new
Term
Why do lunar eclipses last longer than solar eclipses?
Definition
The moon is smaller then the earth
Term
Reason why the terrestrial planets are rocky
Definition
They are too close to the sun and the lighter elements (gas) evaporated
Term
Why do eclipses not occur each month?
Definition
The moons orbit is tilted 5dagrees with respect to ecliptic plane, so it dosnt fall exactly on the path of the sun every month
Term
Cratered surfaces are evidence of …
Definition
Bombardment of smaller objects like meteors/meteorites
Term
Four major techniques used to detect extrasolar planets
Definition
Radial velocity, pulsar timing, transit method, gravitational microlensing, direct imaging.choose 4
Term
Composition of the clouds of Venus
Definition
Venus – covered with deep sulfuric acid clouds in a dense CO2 atmosphere,
Term
When is Venus brightest?
Definition
Inferior conjunction is when Venus passes directly between the Earth and Sun, which happens 5 times in every 8 years, or about once every 1.6 years.
Term
Why is the Martian sky pink?
Definition
Because of all the dust storms.
Term
Cause of the high surface temperature on Mercury
Definition
Mercurys proximity to the sun and its lack of atmosphere.
Term
Why did it take Messenger four years to get to Mercury?
Definition
it had to use other planets gravitational forces as a slinghsot to get to its destination
Term
Difference of the interiors of Uranus and Neptune from that of Jupiter
Definition
Term
Jovian planets in order of increasing atmospheric activity
Definition
saturn, uranus, neptune
Term
Evidence for a subsurface liquid ocean on Europa
Definition
The apparent youth and smoothness of the surface have led to the hypothesis that a water ocean exists beneath it
Term
What is the Roche limit?
Definition
is the distance within which a celestial body, held together only by its own gravity, will disintegrate due to a second celestial body's tidal forces exceeding the first body's gravitational self-attraction
Term
Problem computing circumference from angle of shadow
Definition
(angle(°) )/(360°)= distance/circumference
Term
What are right ascension and declination?
Definition
RA = longitude, DEC = latitude
Term
Two phenomena which prove that the Earth moves
Definition
Stellar parallax and the aberration of starlight
Term
Why is the inner core of Earth solid?
Definition
Higher temperature and especially higher pressure at the center (crystallized iron and some nickel)
Term
Directions of vibration and propagations in S waves and P waves
Definition
S-waves: vibration is perpendicular to the direction of propagation, P-waves: vibration is parallel
Term
Problem on distance, velocity, and time with seismic waves
Definition
t = d/v d = distance, v = velocity, t = time
Term
Composition of the plates on Earth’s surface
Definition
Composition of the plates on Earth’s surface
Term
Problem with the twin formation theory of the formation of the Moon
Definition
It does not explain the density difference
Term
Advantage of the transit method
Definition
It can determine a planet’s diameter, and thus, can also calculate its density
Term
characteristics of inner and outer planets
Definition
It can determine a planet’s diameter, and thus, can also calculate its density
Term
Why is there no planet in the asteroid zone?
Definition
Jupiter’s gravity disrupted the accretion process
Term
What is Bode’s Law?
Definition
an empirical numerical rule which correctly predicts the relative distance of most of the planets. Start with 0, 3, then double each preceding number (6, 12, etc.), add 4 to each number, and divide the result by 10.
Term
planets with plate tectonics
Definition
just earth
Term
What were the canals on Mars as seen by Percival Lowell?
Definition
optical illusions
Term
Uses of radar for studying Venus
Definition
Distance, rotation period, surface features—on Titan, also surface elevation
Term
How does the Cassini mission penetrate the haze of Titan?
Definition
Radar (bright surface = rough, dark surface = smooth)
Term
Location of the ring systems of the giant planets
Definition
Planet ? rings ? satellites
Term
Why is the space near Jupiter a dangerous environment?
Definition
Strong radiation belt
Term
Calculation of the Roche limit
Definition
rR = (16pp/ps)1/3 Rp
Term
Temperature at a distance of one of the Jovian planets
Definition
Inverse square law: T2/T1 = v(d1/d2)
Term
Name of a piece of rock from space which lands on Earth
Definition
Meteoroid (in space), meteor (in sky), meteorite (on Earth)
Term
Dependence of kinetic energy of an asteroid on diameter and speed
Definition
KE = 1/2 mv2, m = d3 ? KE = d3v2
Term
Cause of a meteor shower
Definition
Earth goes through the comet’s orbit while going around the Sun
Term
Wien’s law problem on a logarithmic scale
Definition
Log T = 6.565 – Log ?
Term
Doppler shifts in supernova spectra
Definition
Red shift due to expansion of universe, also blue shift due to mass approaching us at a great velocity (we don’t see the red shift)
Term
Problem to determine main sequence lifetime from mass and luminosity
Definition
t = M/L * 1010 year (M and L are in solar units)
Term
Range of masses of stars which will eventually become white dwarfs
Definition
Minimum of .4 solar masses, maximum of 8 solar masses
Term
Meaning of hydrostatic equilibrium
Definition
Balance between forces of gravity and pressure
Term
Why is our line of sight to the globular clusters clear?
Definition
Many contain RR Lyrae stars, which are pulsating stars, globular clusters can be seen from great distances. Unlike open clusters, in which the stars eventually escape and the cluster dissolves, globular clusters pull the stars into a denser ball, there is not as much dust obscuring the view, and the larger number of stars in these clusters creates a stronger gravity, which pulls them in closer. Globular clusters outline the halo and bulge.
Term
What maintains the spiral structure of the Milky Way?
Definition
Density-wave theory: waves of stars and gas sweep around the galactic disk, we see it as a spiral arm, very wave-like. Some stars have greater gravitational force, which pulls in other stars temporarily and creates a “clump,” where stars can collide and form new stars. SSF Theory: self-propogating star formation, at a random point in the disk of a galaxy, a gas cloud collapses and turns into stars. The stars heat the gas around them, explode as supernovas, generate disturbances that make the surrounding gas clouds collapse and turn into stars. This keeps triggering more gas clouds to collapse and form additional stars, so star formation spreads across the galaxy’s disk, forms a spiral due to the difference in rotation rate between the inner and outer parts of the disk.
Term
What maintains the spiral structure of the Milky Way?
Definition
Density-wave theory: waves of stars and gas sweep around the galactic disk, we see it as a spiral arm, very wave-like. Some stars have greater gravitational force, which pulls in other stars temporarily and creates a “clump,” where stars can collide and form new stars. SSF Theory: self-propogating star formation, at a random point in the disk of a galaxy, a gas cloud collapses and turns into stars. The stars heat the gas around them, explode as supernovas, generate disturbances that make the surrounding gas clouds collapse and turn into stars. This keeps triggering more gas clouds to collapse and form additional stars, so star formation spreads across the galaxy’s disk, forms a spiral due to the difference in rotation rate between the inner and outer parts of the disk.
Term
Problem to determine the mass of the central object by Kepler’s Third Law
Definition
m + M = a3/p2 , m = mass , of smaller object , M = mass of larger object (sometimes not used), a = distance between objects (also semi-major axis), p = years to complete one orbit
Term
The three main types of galaxies
Definition
Spiral (barred and S0), elliptical, and irregular
Term
What is the power source for active galaxies?
Definition
Accretion disks around immense black holes, galaxy centers = black holes of at least 1 million solar masses
Term
Evidence for dark matter in clusters of galaxies
Definition
Evidence comes from observations of the motion of galaxies within clusters; galaxies in clusters orbit too rapidly for their luminous mass. Also, evidence comes from the hot gas they contain—this infers a strong inward gravitational pull on the gas to keep it contained
Term
Celestial objects which can be directly imaged
Definition
Objects whose redshift (z) is less than 1.645
Term
Celestial objects which cannot be directly images
Definition
Objects whose redshift (z) is greater than 1.645
Term
Temperature of matter which emitted the cosmic background radiation, and reason it appears to have a temperature of 2.73 K today
Definition
Temperature = approx. 3000 K. Initially, it had much shorter wavelengths, but those wavelengths have been stretched out over billions of years by the stretching of space associated with the expansion of the universe. 2.73 K is due to a redshift effect because of the expansion of the universe, rather than a cooling effect.
Term
How we know that the expansion rate of the universe is accelerating
Definition
The rate of expansion has been increasing. Dark energy is used to account for this expansion rate. Normal/dark matter would act to slow the expansion rate. With the universe’s thinning density over time, it means that the accelerating effect of the repulsive dark energy component dominates the decelerating effect of the attractive gravitational force.
Term
The four distances used in cosmology
Definition
Luminosity distance, Now distance, Light-travel-time distance, and Angular-size distance
Term
Objects which can be used to test the angular-size vs. red shift relation at high redshift
Definition
Standard yardstick
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