Studied by 2 peopleThe number 206265 is
the number of arcseconds in one radian
Galileo's observations of the phases of Venus proves
that Venus orbited the Sun
Galileo's telescopic discoveries of mountains on the Moon and spots on the Sun were controversial because they suggested that the Sun and the Moon
were not perfect spheres
Parallax is
the apparent motion of an object due to the motion of the observer
A blackbody is
a heated object that emits a characteristic spectrum of radiation
If two stars have the luminosity, but star B is 2 times as far away as star A, then the flux from star B is how many times that of star A?
1/4 times
A standard candle is a source with
a known intrinsic luminosity but different observed fluxes
The Tully-Fisher relation is
a means to determine the intrinsic luminosity of a galaxy
Cepheid variable stars are useful because
they relate the period of variability to its intrinsic luminosity
Newton concluded that some force had to act on the Moon because
a force is needed to pull the Moon away from straight line motion
Which of the following is NOT evidence of dark matter?
the accelerated expansion of the universe
Newton's law of gravitation
-GMm/r^2
Kepler's law of orbits
planetary orbits are ellipses
Kepler's law of periods
P^2=a^3
Kepler's law of areas
planets sweep out equal area in equal time
Circular Velocity
-GMm/r
Gravitational potential energy
sqrt(2GM/r)
Escape velocity
sqrt(GM/r)
Which of the following is NOT one of Kepler's laws of planetary motion?
the gravitational force between two objects varies inversely with the distance between them
A comet has an orbital period of 8 years. What is the average distance of this comet from the Sun?
4 AU
If satellite B is four times the distance of satellite A from the Earth, then the circular velocity of satellite B is how many times that of satellite A
1/2
If satellite B is four times the distance of satellite A from the Earth, then the escape velocity of satellite B is how many times that of satellite A?
1/2
If satellite B is four times the distance of satellite A from the Earth, then the magnitude of the gravitational binding energy of satellite B is how many times that of satellite A?
1/4
If satellite B is four times the distance of satellite A from the Earth, then the magnitude of the gravitational force due to the Earth on satellite B is how many times that of satellite A?
1/16
If a galaxy indicates a redshift of z = 0.1, then it is moving away at
10% the speed of light
If a galaxy is receding with a velocity of 1400 km/sec, and the Hubble constant is H0 = 70 km s^-1 Mpc^-1. How far away is it in Mpc?
20 Mpc
The resolution of Olber's paradox requires that
the universe is finite and temporal
If a galaxy A is four times more distant than galaxy B, then according to Hubble's law, galaxy A will recede
4 times faster
The distribution of galaxies on large scales in the universe
shows a pattern of walls, voids, and filaments
The cosmic microwave background
is a blackbody spectrum, shows the motion of the earth and the galaxy through the universe, shows evidence quantum fluctuations from the early universe, has a temperature of about 3 degrees Kelvin
Which of the following is not a means to date the age of the universe?
the rotation speed of the Galaxy
The Einstein Principle of Equivalence states
gravity and acceleration are equivalent
The bending of light by gravity as it goes around a massive object is known as
gravitational lensing
If the sun suddenly became a black hole without gaining or losing mass, what would happen to the earth?
the Earth would continue in its orbit without a change
The Schwarzschild radius is
the radius of the event horizon of a black hole
The Schwarzschild radius of a star 9 times the mass of the Sun would be
9 times that of the sun
If the Sun has a Schwarzschild radius why isn't it a black hole?
It is too big
The Friedmann equation describes
the evolution of the cosmic scale factor
The discovery of dark energy was the observation that the recession speed of galxies was
slower in the past
As a consequence of cosmic expansion light traveling between two galaxies
travels a longer distance than the distance between galaxies when the light was first emitted
If the average distance between galaxies now is 2 times what it was at some time in the past, and the present scale factor is a(t) = 1.0 then the cosmic scale factor in the past was
1/2
The cosmological principle states
the universe is isotropic, homogenous, and the laws of physics are the same everywhere
Note
Flashcard