Newton.s explanation of Kepler.s Laws relied upon a force that
acts on all objects.
The Moon rotates on its axis so that it always keeps the same side
toward the Earth.
In comparison to the established, earth-centered theory, the Copernican Theory of planetary motion made
predictions that were of
about the same accuracy.
You are standing in an elevator that is accelerating upward at 1m/s^2Which of the following pairs of forces is
an action-reaction pair that has to be exactly equal and opposite to each other?
The force that the .oor of the elevator exerts on you and the force that you exert on the .oor of the
A model in which the Moon forms by breaking away from the Earth would predict that the Moon.s orbit should be
in the plane of the Earth.s equator.
An atom of ordinary hydrogen consists of an electron and a
Early (before 1970) theoretical estimates of the number of near-Earth asteroids were very low because the astronomers of that time
did not realize that Jupiter.s gravity was de.ecting asteroids from the Belt.
Kuiper Belt objects are usually made of
ice and possibly frozen gas.
Astronomy is known for claiming to have measured many things that cannot possibly be probed directly. These measurements are made by combining actual measurements with
The fact that the International Space Station is above most of the Earth.s atmosphere is important because it means that
there is no air friction to slow the space station down.
The temperature of a gas measures the
energy of motion of its atoms or molecules.
an extensive ring system made of ice-covered rocks.
Protostars are very bright because of their large surface areas. Most of this energy comes out as
infra-red light with wavelengths too long to see with an ordinary telescope.
Liquid water tends to permanently remove carbon dioxide from the atmosphere of a planet by
forming an acid which reacts with calcium in rocks.
What total force will cause an object with a mass of 100kg to gain 100 meters per second every second?
The stars of the Milky Way are all near a great circle on the Celestial Sphere. This great circle
is none of the other things listed here.
A descending convection current in the Earth.s mantle is expected to cause
a deep ocean trench where tectonic plates are pulled together.
one of the four most common elements in the universe.
In comparison to RR Lyra variables, Cepheid variable stars are
more luminous and less common.
When a large interstellar cloud collapses, it usually
fragments into several smaller clouds which then form stars.
The main reason that the SETI@home system needs to use the computing power of 5.2 million participating home computers is that
they are collecting and analyzing signals on millions of di¤erent radio channels.
The Viking Landers carried out several experiments on Martian surface soil. One of those experiments, the Pyrolytic Release Experiment gave a positive result for the presence of life forms. That result was interpreted to mean
nothing because a sterilized control sample gave the same result.
Supernova explosions tend to
form elements heavier than iron.
Had Jupiter ignited, we would be living in a multiple star system. Such systems
are quite common.
At 10pm, you see that the pointer stars of the Big dipper and the star Polaris are arranged in a vertical line. How long, give or take a few minutes, would you need to wait to see them arranged in a horizontal line?
The Lunar Maria are actually
ancient lava .ows.
The absorption and re-radiation of infrared light by gases such as carbon dioxide is the key process in the
The oxygen atom in a water molecule
carries a negative electrical charge.
The stratosphere is where one .nds
smoke and dust lingering for years.
So far (as of 2008), the planet Mercury has been visited by
two successful space probes.
what planet has a solar day that is very close to an Earth day in length.
He found this angle to be slightly less than 90 degrees. Suppose that he had, instead, found the angle to be more than 90 degrees. In that case, which of the following conclusions would he have been forced to accept?
Moonlight is not actually re.ected sunlight.
The angle between a planet.s rotation axis and the perpendicular to the plane of its orbit determines the variability of its seasons. For Jupiter, this axial tilt angle is
only a few degrees so seasons are negligible.
moving at around 5 miles per second. Suppose that it is desired to lower it to a new circular orbit, sliightly closer to the surface. fires its main rocket engine in a short burst to slow its speed to 4.96 miles per second. What must it do next?
Slow its speed again by a bit when its distance from the Earth stops decreasing.
The velocity of sound waves is roughly the same for all wavelengths. Suppose that a sound wave has a wavelength of one meter and a frequency of 250Hz. The wavelength of a 1000Hz sound wave would then be
A star is found to have absolute magnitude -1 and apparent magnitude 19. How far away is it?
Icy objects were ejected outward from the neighborhood of the Jovian planets to form
the Oort Cloud.
After a comet.s closest approach to the Sun, its tail points
ahead of its direction of motion.
Compared to a magnitude 11 star, a magnitude 1 star would be
The star Wemadeit shows a stellar parallax angle of 0.2 seconds of arc while the star Waytoofar shows a stellar parallax angle of 0.3 seconds of arc. From this, you can conclude that
Waytoofar is closer to our Sun than Wemadeit.
The number of moons of Venus is
The .rst successful soft landing on the Moon was Surveyor 1 in
Which of the following objects has a magnetic field similar in intensity to the Earth.s feld?
The density of water is 1000kg/m^3while the density of iron is 7800kg/m3. Which of the following values is a
plausible value for the density of a terrestrial planet?
The rotation axis of Saturn is
inclined at an angle to the perpendicular that is similar to Earth.s rotation axis.
Kepler found that the orbit of Mars is best described as
A star that evolves o¤ the main sequence in about 10 million years probably has
about 20 times the mass of our Sun.
Fred Zveistein has a new theory that predicts that some material objects can go faster than light. Fred presents his new theory at a scienti.c meeting. Which of the following would be the most likely reaction of the scientists at the meeting to this new development?
There is great disinterest because there is no need to replace a theory that has passed every observationaltest. Nobody at all comes to Fred.s talk.
Which of the following phases of the Moon would be seen high in the south at sunset?
When an interstellar cloud fragment does not have enough mass to form a star powered by nuclear fusion, but gets hot enough to glow for a while, it is called
a brown dwarf.
An astronomical unit is defined to be
the average distance from the Earth to the Sun.
Which of the moons has geysers of water shooting out through cracks in the moon, indicating a subsurface ocean?
Which of the following statements describes the relation between what we observe and the predictions the nebular model of the formation of the Solar System?
The model predicts rocky planets nearest to the Sun and we observe rocky planets there.
The total luminosity, at all wavelengths, of the source Sgr A* is approximately
a million times the luminosity of our sun.
The frst soft landing on Mars was by the
The spacecraft Galileo
went into orbit around the planet Jupiter and dropped a probe into its atmosphere.
Call the time it takes Venus to orbit the Sun a .venusian year.. Call the time it takes Venus to rotate once on its axis relative to the distant stars a .venusian sidereal day..Which of the following statements about these two time periods is true?
A venusian year is shorter than a venusian sidereal day.
Our sun is roughly at the center of
the visible part of the Milky Way.
The X-rays that reveal the possible presence of a black hole are the result of
matter heating up as it falls toward the hole.
Pressure waves are transmitted through
both solids and liquids.
If you are looking down over the south pole of the Earth, you will see the Earth rotate
Which layer of the Earth has a thickness of only about ten miles?
A type I supernova occurs when
a white-dwarf collapses.
Which of the following planets or moons has an atmosphere consisting mainly of Hydrogen and Helium?
In the Earth.s atmosphere, the percentage that is Oxygen is roughly
Venus retains a dense carbon dioxide atmosphere because
there is no liquid water there.
Because the Earth goes around the Sun, we see the Sun move
eastward along the ecliptic.
An ion rocket engine produces 50 Newtons of thrust. What acceleration can it give to a space probe with a mass of 10,000kg?
. 0.005 m/s^2s
One property of a model such as the shape of the Earth is the number of adjustable parameters it has . the number of numbers that are needed to determine the model. For a model to be regarded as .elegant., this number
should be small.
If the acceleration of an object is zero, its speed
is not changing.
Which of the following spectral types would you expect to look red in color?
The mass of a carbon atom is 12.00amu while the mass of a deuterium atom is 2.014amu. If a gamma ray photon splits a carbon atom into six deuterium atoms, how much energy is converted into mass?
In the Hertzsprung-Russell Diagram shown, which point represents a star of type B with absolute magnitude -5?
Near-Earth asteroids of the sort that caused the Tunguska blast and the Barringer Meteor Crater are
not likely to be located within the next few years.
The closest star to the North Celestial Pole that is visible to the naked eye is
The sun usually sets in the
A single sugar phosphate chain with amino acids attached along it describes a molecule of
Of all the things that might go wrong with distances found by using the method that astronmers refer to as the "distance ladder," which of these is the one that an astronomer would say is most likely?
Distant objects are not behaving the same as nearby objects.
Comets usually follow orbits which are
elliptical with aphelia far outside the orbit of Mars.
When the Earth passes through the orbit of a broken-up comet, we see
a meteor shower.
One conclusion that was drawn from the gradual slowing of the radio signals from the Crab Nebula was that they were probably
of natural origin.
From the broadening of its spectral lines, one can determine a star.s
In a Hertzsprung-Russell diagram, the absolute brightness of stars increases going
Temperatures on the surface of Mercury are
extremely varied because it has no atmosphere to spread the heat.
The blue color of the planet Uranus is caused by the presence in its atmosphere of
The Earth.s Moon
is 1/4 the size of the Earth, which is unusually large for a moon.
In the ancient Greek theory of gravity, everything was attracted to the center of the universe. In Newton.s theory of gravity, everything was attracted
to every other object in the universe.
Galileo.s observation that Venus goes through a full cycle of phases just like the Moon was signifcant mainlybecause that is
not what the Ptolemaic Theory predicted.
The .rst spaceprobe to send back pictures of the surface of Venus was
an atmosphere of carbon dioxide with about 90 times the surface pressure of Earth.s.
The apparent brightness of our Sun is roughly 1000 watts per square meter. At a distance of 30 times the Earth-Sun distance, the apparent brightness of our Sun would be
1.1 watts per square meter.
The Ptolemaic model of the Solar system accounted for the daily rising and setting of the Sun by assuming that
The Sun moves around the Earth once a day.
The Oort cloud of our Sun reaches
at least a quarter of the way to the nearest star
The statement that the orbit of each planet is an ellipse with the Sun at one focus is due to
The Cassini-Huygens spacecraft
Went into orbit around the planet Saturn.
Because the radiant of the Lyrid meteor shower is in the constellation Lyra, you can conclude that
the Earth is moving toward Lyra when it passes through the remains of the comet.
Our Sun is a type G2V star on the main sequence. As it ages and uses up its fuel we expect it to
remain a G2V star until it leaves the main sequence.
Earth.s orbit is currently elliptical enough to make the intensity of sunlight vary by 6 percent. The shortest Earth-Sun distance (and highest intensity sunlight) occurs
The moon Miranda is peculiar because it
has a surface feature that looks like a giant check mark.
The magnetic feld of Mars is
The Oort Cloud is located
far beyond the orbit of Pluto.
Think of the .front.of a telescope as the end that light enters. A telescope with Newtonian Focus has the eyepiece
sticking out the side near the front.
The word .Parallax.in the term .Spectroscopic Parallax.is used because that term refers to
a method for .nding distances to stars.
When a red giant star begins to burn helium, its diameter
decreases but not to its main sequence size.
In comparison to Kepler.s Laws of Planetary Motion, Newton.s theory of Universal Gravitation predicted almost the same motions, but with small corrections due to
the gravitational attractions between di¤erent planets.
Which of the following objects is a moon of Jupiter?
in a spiral galaxy, long-lived stars such as our Sun
move in and out of spiral arms.
The point at which even an outwardly directed light ray is pulled into a black hole is called the
Black holes are often discovered by observing the shifting of spectral lines in an ordinary star that they are orbiting. Careful measurements of the shifting spectral lines can provide
only a minimum mass for the black hole.
Which of the following types of radiation has the highest frequency on this list?
Galileo.s approach to understanding moving objects was to
build things that he could measure.
As of 2009, how many space probes have .own past Uranus?
Which of these planets has a rotation axis that is inclined in much the same way as that of Earth?
A star with an absolute magnitude of5:7 and an apparent magnitude of 1:2 would appear in our sky as a star
of dazzling brightness.
Suppose that an object with a mass of one kilogram and an object with a mass of two kilograms are both in free fall near the Earth.s surface. As compared to the one kilogram object, the two kilogram object accelerates
the same because gravity pulls on it more strongly and it has more inertia.
You are standing at the edge of a great desert at noon time. In front of you is a sea of hot sand. Behind you is the coolness of a green and growing forest. Which way is the wind most likely blowing?
toward the desert.
The star Gliese 581 is of particular interest mainly because it is
known to have two terrestrial-size planets near its habitable zone.
A planet whose atmospheric pressure is exactly at the triple point of water and whose surface temperature has a range that includes the triple point will have
water as ice or vapor, depending on the temperature.
Which of the following spacecraft is the only one to have .own past Neptune?
To solve this problem, the inventor
proposes to use the electricity from his generator to run a pump that takes water from the foot of the dam and puts it back up into the reservoir.
a. This idea will fail because it
This idea will fail because it takes exactly the same amount of energy to raise the water up as it releases
when it comes down. The scheme will not generate energy for other uses.