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ASTR17: Solar System
Final
166
Astronomy
Undergraduate 2
12/13/2010
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Term
How many stars are in our Solar System?
 Definition
One
Term
How many centimeters are in one kilometer?
 Definition
10^6
Term
The distance from the sun to the nearest star is...
 Definition
...several thousand times further away than Pluto.
Term
On a "cosmic calendar," in which the universe is imagined to have began on January 1st and the entire history of the universe is compressed in one year, when did our Solar System form?
 Definition
September
Term
Constellation
 Definition
A region of the celestial sphere of the sky
Term
Arcsecond
 Definition
An angle equal to 1/3600th of one degree
Term
A 6th magnitude star appears roughly 2.5 times brighter than a star of magnitude...
 Definition
...7.
Term
Precession causes...
 Definition
...the locations of the celestial poles to change among the stars.
Term
If the Sun rises from the horizon in the southeast, in which direction will it set?
 Definition
In the southwest.
Term
What contributes to the occurrence of summer in North America?
 Definition
The sun passes higher in the sky then and the daytime is longer then.
Term
The sun appears directly overhead...
 Definition
...at different places in the Earth's tropics at different times of the year.
Term
The Summer Solstice is...
 Definition
...a location on the celestial sphere of the sky where the Sun appears as far north of the celestial equator as it can reach and an event that happens on or about June 21st.
Term
What contributes to the occurrence of ice ages on Earth?
 Definition
Precession, slight changes in how much Earth's axis of rotation is tilted with respect to the plane of its orbit, and slight changes in how closely the Earth's orbit approximates a perfect circle.
Term
The synodic period of the moon is...
 Definition
...the time between successive new moons and is approximately 29.5 days.
Term
A waxing crescent moon is visible...
 Definition
...near the Western horizon just after sunset.
Term
The saros cycle...
 Definition
...was used in ancient times to predict eclipses.
Term
An eclipse season is the period of time during which the...
 Definition
...Earth and Sun align with the nodes in the Moon's orbit.
Term
When the new moon is too far from Earth, the most dramatic eclipse that observers on Earth may see is...
 Definition
...an annular solar eclipse.
Term
During a total lunar eclipse...
 Definition
...the Moon will glow a faint coppery red.
Term
If the Earth did not rotate, could we still define the ecliptic?
 Definition
The rotation of the Earth does not define the ecliptic. The ecliptic--an imaginary line traced out by the sun over the course of a year--is the path that all the planets take. We have this line because we REVOLVE around the sun. So if the Earth didn't REVOLVE around the sun, we wouldn't have an ecliptic.
Term
Why does the Moon show different phases as seen from Earth?
 Definition
The phases of the Moon are caused by alignment of the Moon and the Sun in the sky. The orientation of this alignment determines the phase of the moon. At new moon, for example, the angular distance of the Sun and the Moon is small and at first quarter it's 90 degrees; so at new moon, we don't see much but at first quarter we see half of the light side of the moon.
Term
The ancient Greeks were able to determine the size of the Earth accurately by...
 Definition
...comparing the noon height of the Sun in the sky at two different Egyptian cities on the same day.
Term
Tycho Brahe did not accept which model of the universe?
 Definition
Heliocentric
Term
The correct orbital paths of the planets were first worked out by...
 Definition
...Kepler.
Term
Kepler used the detailed observations of which famous astronomer in order to work out elliptic orbits?
 Definition
Tycho Brahe
Term
Whose model of the Universe was in this order: Earth, Mercury, Venus, the Sun, Mars, Jupiter, and Saturn?
 Definition
Ptolemy
Term
If two asteroids orbit the Earth, one of which orbits in a circle, the other orbits in an ellipse, which asteroid has a longer orbital period?
 Definition
They have the same orbital periods.
Term
What are some of Galileo's discoveries?
 Definition
Jupiter's moons, mountains on the Earth's Moon, sunspots, and the Milky way is composed of many millions of stars.
Term
What did Galileo's observations of the gibbous phase of Venus prove?
 Definition
That Venus orbited the Sun.
Term
What means "an idea in science that is still considered tentative and not well tested"?
 Definition
Hypothesis
Term
Newton concluded that some force had to act on the Moon because...
 Definition
...a force is needed to pull the moon away from a straight-line motion.
Term
The Force of Gravity
 Definition
Always acts to pull objects toward each other, the strength of the force depends upon the mass of both of the interacting objects, and the strength of the force weakens with increasing distance between the two objects.
Term
What does motion with a constant speed in a circle require?
 Definition
Continuous Acceleration
Term
True of False: You pull the Earth upward with the same amount of force that the Earth pulls you downward.
 Definition
True
Term
True of False: In the absence of air resistance, all objects on Earth's surface accelerate toward the ground at the same rate.
 Definition
True
Term
True or False: Whenever no force acts on it, a moving object will continue to move in a straight line at a constant speed.
 Definition
True
Term
True or False: A rocket ship must achieve escape velocity from the Earth in order to achieve orbit around the Earth.
 Definition
False
Term
True or False: The force that keeps the Moon in its orbit has the same cause as the force that causes apples to fall from trees.
 Definition
True
Term
What is geosynchronous orbit?
 Definition
One where the orbiting object is always above the same location on Earth's surface
Term
What is a measure of the amount of matter an object contains?
 Definition
Mass
Term
Weight depends entirely on what?
 Definition
The forces that act upon an object
Term
Tidal forces from the Moon cause ocean water to rise...
 Definition
...on the two ends of the Earth that are toward and away from the Moon.
Term
Tidal forces between the Earth and the Moon are responsible for...
 Definition
...the Moon always keeping the same face toward Earth, a gradual slowing of the speed that Earth spins, and a gradual increase in the distance from Earth to the Moon.
Term
True or false: Infrared radiation has photons that contain less energy than visible light photons.
 Definition
True
Term
What is the approximate wavelength of red light?
 Definition
700nm
Term
A "sidereal drive" is useful for telescopes because with one...
 Definition
...objects would disappear from the telescope's view as the Earth turns away from them.
Term
What are some advantages of the Hubble Space Telescope over ground-based telescopes?
 Definition
Stars don't twinkle when observed from space, it can observe infrared and ultraviolet light as well as visible light, it never has to close because of poor weather, and it's view is not affected by light pollution.
Term
True or false: The radio form of electromagnetic radiation emitted in space can be observed easily by equipment located at sea level.
 Definition
True
Term
A 6-inch wide telescope can see objects how many times fainter than a 3-inch wide telescope can see?
 Definition
4 times fainter
Term
True or false: X-ray telescopes allow astronomers to see through clouds in Earth's atmosphere.
 Definition
FALSE.
Term
True or False: It is common for images seen in a properly working astronomical telescope to appear upside down.
 Definition
True
Term
True or false: With the right eyepiece lens, a small backyard telescope can have a magnifying power as great as the largest telescope in the world.
 Definition
True
Term
True of False: Simultaneously combining the images seen by different telescopes is a trick that can greatly improve resolving power.
 Definition
True
Term
True or False: The most important ability of an optical telescope is its ability to make objects appear brighter.
 Definition
True
Term
What is the fundamental reason radio telescopes are built so much larger than optical telescopes?
 Definition
Radio waves have much longer wavelengths than visible light waves.
Term
In the Kelvin temperature scale, room temperature is roughly what?
 Definition
300K
Term
What is the coldest temperature physically possible, in the Kelvin temperature scale?
 Definition
0K
Term
True or False: A perfect blackbody absorbs all wavelengths of electromagnetic radiation.
 Definition
True
Term
True of False: A perfect blackbody emits all wavelengths of electromagnetic radiation.
 Definition
True
Term
True or False: A perfect blackbody emits more electromagnetic radiation of higher frequency if it is hotter.
 Definition
True
Term
True or False: A perfect blackbody reflects no electromagnetic radiation.
 Definition
True
Term
True or False: A perfect blackbody's spectrum results from the motion of electrically neutral particles within its atoms.
 Definition
False
Term
An atom that is excited can...
 Definition
...emit a photon when the electron moves to a lower energy level
Term
What number in an atom determines which chemical element the atom represents?
 Definition
The number of protons
Term
If atoms of the same chemical element have different numbers of what, the atoms are said to be different isotopes of the same element?
 Definition
Different numbers of neutrons
Term
Why don't we see the visible wavelength spectral lines of hydrogen in the spectra of stars with temperatures that are several times hotter than our Sun?
 Definition
The stars are so hot that most of the hydrogen is ionized, and these atoms cannot absorb photons of the correct energies.
Term
If the spectral line of Hydrogen is observed to have a wavelength of 656.28nm, but is observed in the spectrum of a star to have a wavelength of 656.49nm, then the spectrum of the star is...
 Definition
...redshifted and moving away from us.
Term
Why did Copernicus's model of the Solar System become popular in Europe?
 Definition
First because it was simpler than Ptolemy's model and second because Protestants liked to challenge Catholic authority.
Term
Problems of Reflecting Telescopes
 Definition
1. Serious optical distortion that limits their usefulness
2. Shorter wavelengths bend more than longer wavelengths, so blue light, for example, having shorter wavelengths, come to a focus closer to the lens than does red light. So, if you focus the eyepiece on the blue image, the other colors are out of focus.
3. The primary lens is more expensive than a mirror of the same size.
Term
Conservation of Angular Momentum
 Definition
When a mass is made more compact, it spins faster.
Term
The Sun's Corona...
 Definition
...has a higher temperature than the photosphere, but contains less total heat that the photosphere.
Term
Average temperature of the Sun's chromosphere?
 Definition
8,000K to 10,000K
Term
True or False: The density of the chromosphere is much less than the gas density within the photosphere.
 Definition
True
Term
Irregularities within the chromosphere's structure?
 Definition
Spicules and prominences
Term
True of False: When the chromosphere is viewed in some ultraviolet wavelengths, it outshines the photosphere.
 Definition
True
Term
True or False: Humans didn't know of the chromosphere until the "space age" of the 20th century.
 Definition
False.
Term
Granulation is caused by what?
 Definition
Convection in the gas below the photosphere
Term
Why are sunspots dark?
 Definition
The strong magnetic field inhibits the currents of hot gas rising from below.
Term
A solar flare...
 Definition
...causes geomagnetic storms and aurorae on Earth and releases most of its tremendous energy in non-visible light.
Term
The observation that the Sun rotates faster at its equator than at its poles...
 Definition
...proves that the Sun isn't a solid, twists the Sun's magnetic field around which generates the 11-year cycle, was discovered by Galileo, and means that the Sun's limb at its equator shows a greater Doppler effect than the Sun's poles.
Term
What is the Maunder Minimum?
 Definition
A 70 year long period between 1645 and 1715 in which almost no sunspots were seen and Earth's climate was significantly cooler.
Term
How might the interior structure of the Sun be explored?
 Definition
Through observing how the surface of the Sun vibrates after a solar flare occurs.
Term
How is the proton-proton chain of nuclear fusion inside the Sun able to occur?
 Definition
The nuclear strong force is stronger than the force of electromagnetic repulsion between to protons.
Term
Experiments to detect neutrinos coming from the sun originally detected how many less neutrinos than expected?
 Definition
1/3 as many neutrinos as expected.
Term
Why can't massive stars generate energy through the nuclear fusion of iron into heavier elements?
 Definition
Iron has the lowest mass per nuclear particle of all nuclei.
Term
How long ago did our Universe form?
 Definition
14 billion years ago
Term
How long ago did our Sun and planets form?
 Definition
4.6 billion years ago
Term
How were the atoms of substances most commonly found on Earth first created?
 Definition
By nuclear fusion reactions inside stars that are now long dead.
Term
Condensation in the Solar nebula probably led to the formation of what?
 Definition
Icy grains beyond the present orbit of Jupiter, metallic grains near the present orbit of Mercury, and silicate grains near the present orbit of Earth.
Term
The planets all lie in nearly the same plane resulting in a disk-like structure for the Solar System. This disk-like structure is believed to exist because of...
 Definition
...conservation of angular momentum as the Solar Nebula contracted.
Term
Once planetesimals in the Solar Nebula grew larger than several kilometers in size, they would have grown faster than smaller planetesimals. Why?
 Definition
Because their stronger gravity would pull in more material.
Term
Accretion among freshly condensed, very small grains, in the Solar Nebula would have been aided by what?
 Definition
Electrical forces
Term
Planets orbiting stars other than our Sun have been detected...
 Definition
...in photographs taken by the Hubble Space Telescope, by small Doppler Shifts they cause in the spectra of the stars that they orbit, and by a small dimming of their stars' light that happens sometimes when they pass in front of their stars.
Term
Why were the first planets discovered around other Sun-like stars surprising?
 Definition
These planets were massive, Jovian-type planets orbiting extremely close to their stars. Jovian planets should not have been able to form that close in.
Term
The Solar Nebula was cleared away by the effects of...
 Definition
...impacts by planetesimals onto protoplanets, the solar wind, the Sun's radiation pressure, and ejection of planetesimals because of close gravitational encounters with protoplanets.
Term
What is evidence that Earth differentiated?
 Definition
That Earth has an average density that is higher than the density of the crust.
Term
What evidence is there that Earth has a liquid core?
 Definition
That no S waves penetrates the core.
Term
Where does Earth's magnetic fields direct charged particles?
 Definition
Toward the poles to produce aurorae.
Term
Why is there a difference between the rugged and jagged peaks of the Himalayas and the smooth, rolling peaks of the Appalachians?
 Definition
The Appalachians are much older and have been smoothed by erosion?
Term
The oxygen in the Earth's atmosphere...
 Definition
...was added to the atmosphere in its current form by living things, was manufactured inside stars, and is not as abundant in the atmosphere as nitrogen.
Term
What is slow surface evolution on the Moon at the present time limited to?
 Definition
The effects of occasional impacts
Term
Where are the lunar maria more abundant?
 Definition
On the near side of the Moon
Term
How did the Moon form?
 Definition
The Moon formed from the vaporized splatter of an exceptionally giant impact to the Earth.
Term
Which is older--the Moon's highlands or the Maria?
 Definition
The Moon's highlands
Term
Why are the Moon and Mercury no longer geologically active?
 Definition
They're too small
Term
Which hypothesis explains Mercury's even distribution of long, steep scarps?
 Definition
The hypothesis that Mercury shrank slightly as its interior cooled
Term
What is Mercury's rotation to revolution rate?
 Definition
Mercury rotates on its axis for every two revolutions.
Term
Why is the surface of Venus the hottest in the Solar System?
 Definition
The massive amounts of carbon dioxide in the atmosphere.
Term
Which property of Venus is not similar to Earth?
 Definition
It's rotation
Term
What has the surface of Venus primarily been mapped by?
 Definition
Radar
Term
True or False: The surface of Venus is obscured by a thick cover of sulfuric acid clouds.
 Definition
True
Term
True or False: The planet's cloud cover acts to keep the surface cooler than it would be otherwise.
 Definition
True
Term
True or False: The planet's cloud cover originates from volcanic activity on the surface.
 Definition
True
Term
True or False: The density of the atmosphere is roughly 90 times the density of Earth's atmosphere at sea level.
 Definition
True
Term
True or False: The surface of Venus is eroded by powerful winds that generally exceed 100 kilometers per hour.
 Definition
False
Term
What evidence suggests that the surface of Venus is all the same relatively young age, while the ages of parts of the surface of Mars range from very old to much younger?
 Definition
The impact craters on Venus are randomly distributed across the surface, while the while the impact craters on Mars are concentrated in the southern hemisphere.
Term
What is the leading hypothesis to explain the uniform age of the surface of Venus?
 Definition
Venus' surface periodically goes through a catastrophic melting of the entire surface.
Term
How rapidly a planet loses its atmosphere depends on a planet's what?
 Definition
Mass, atmospheric composition, temperature, and exposure to ultraviolet radiation from sunlight.
Term
The Martian sky generally appears...
 Definition
Pinkish, die to fine iron oxide dust in the Martian hemisphere
Term
The flow patters found on the surface of Mars imply what?
 Definition
Billions of years ago, Mars had water flowing on its surface, was warmer, and had a denser atmosphere.
Term
What do the Martian polar caps contain?
 Definition
Water ice and carbon dioxide ice
Term
Why do volcanoes on Mars grow to the most enormous sizes in the Solar System?
 Definition
Mars has a lower surface gravity than Earth or Venus and plate tectonics does not happen on Mars.
Term
True or False: Mars's axial tilt is remarkably similar to that of Earth.
 Definition
True
Term
True or False: Dust geysers apparently spray from Martian sand dunes at the start of its Southern springtime.
 Definition
True
Term
True or False: Mars has the greatest uncompressed density of the four terrestrial planets.
 Definition
False
Term
True or False: Mars has two small moons that most likely are asteroids captured from the Asteroid Belt.
 Definition
True
Term
True or False: The period of Mars's rotation is remarkably similar to the Earth's.
 Definition
True
Term
Why are Jovian planets so much more massive than the terrestrial planets?
 Definition
Because the Jovian planets were created so far from the sun, they were made of large ice particles. When all of these particles accreted, it made a massive cores that had more gravity that could pull in more hydrogen and helium.
Term
Plate tectonics. Why does it happen? How and why does it affect the continental crust differently from the ocean floor crust, and what is one example of a land feature that results from plate tectonics?
 Definition
Plate tectonics happens because of slow convection in the underlying mantle and it breaks the crust into plates and moves these plates in different directions. It affects the continental crust differently from the ocean floor crust because the ocean floor crust is more dense and just slides under the continental crust during subduction. Typical land features that result from plate tectonics are mountains, oceanic ridges, and volcanoes. These land features are caused by the plates converging and diverging.
Term
All the Jovian planets have atmospheres rich in what element?
 Definition
Hydrogen
Term
Belt-Zone Circulation
 Definition
Atmospheric circulation that entails clouds forming dark belts and light zones that circle the planets like striped on a child's ball
Term
True or False: All of the planets have giant circulating storms.
 Definition
True
Term
The cores of Jupiter and Saturn are composed of what element?
 Definition
Liquid Hydrogen
Term
Why are Uranus and Neptune sometimes called ice giants?
 Definition
They contain a great deal of water, probably in solid form
Term
Why are the outer planets hydrogen-rich and low density?
 Definition
Because they formed in the outer solar nebula where water vapor could freeze to form tremendous amounts of tiny ice particles. These hydrogen-rich ice particles accreted to begin forming the planets; and, once the growing planets became massive enough, they could draw in more hydrogen gas directly by gravitational collapse.
Term
True or False: All of the Jovian worlds have large satellite systems.
 Definition
True
Term
The moons around the Jovian planets can be classified into what two groups?
 Definition
Regular satellites and irregular satellites.
Term
What are regular satellites?
 Definition
Tend to be large and orbit in the prograde direction, relatively close to their parent planet, with low inclinations to the planet's equator
Term
What are irregular satellites?
 Definition
Smaller than regular satellites, sometimes have retrograde and/or highly inclined orbits, and are generally far from their parent planet
Term
What do astronomers believe about the formation of regular satellites versus the formation of irregular satellites?
 Definition
that regular satellites formed approximately where they are now as the planets formed but that the irregular satellites are mostly, if not all, captured objects
Term
What two processes affect the Jovian moons?
 Definition
1. The orbits of some moons may have been modified by interactions with other moons, so that they now revolve around their planet in mutual resonances. This same process might allow moons to affect the orbital motions of particles into planetary rings.
2. The second process allows tides to heat the interiors of some moons and produce geological activity on their surfaces, including volcanoes and lava flows.
Term
Where is the largest ocean in the Solar System?
 Definition
Below the clouds of Jupiter
Term
Four important ideas of Jupiter's atmosphere
 Definition
1. The atmosphere of Jupiter is hydrogen-rich, and the clouds are confined to a shallow layer
2. The cloud layers lie at certain temperatures within the atmosphere where ammonia and ammonium hydrosulfide, and water can condense to form ice particles
3. The belt-zone circulation is driven by high- and low-pressure areas related to those on Earth
4. The major spots on Jupiter, although they are only circulating storms can remain stable for decades or even centuries
Term
Describe Jupiter's ring.
 Definition
Jupiter's ring particles are very dark and reddish, so it is rocky rather than icy. The ring particles are also mostly microscopic. Jupiter's ring is very bright when illuminated from behind.
Term
The Roche Limit
 Definition
The distance from a planet within which a moon cannot hold itself together by its own gravity
Term
How many moons does Jupiter have?
 Definition
Over 60
Term
Describe Callisto.
 Definition
Outermost of Jupiter's four largest moons (Galilean moons). Surface is dark, dirty ice heavily pocked with craters. Interior is a mixture of rock and ice and has a weak magnetic field. Callisto, also, has no core.
Term
Describe Ganymede.
 Definition
Ganymede is larger than Mercury, and over three-quarters the diameter of Mars. Ganymede is the largest moon in the Solar System. Magnetic field about 10% as strong as Earth's.
Term
Tidal heating
 Definition
The frictional heating of a body by changing tides
Term
Describe Europa.
 Definition
Ice surface. Geologically active surface. Liquid-water ocean.
Term
Describe Io.
 Definition
The temperature averages 130K (-225F) and the atmospheric pressure is really low. Io's this atmosphere is smelly with sulfur. No ice/water on Io. Driest world in our Solar System. Crust is probably silicate rock. Tons of volcanic activity.
Term
True or False: Saturn is less dense than water.
 Definition
True
Term
Atmosphere rich in what elements?
 Definition
Hydrogen and helium
Term
Saturn's magnetic field is how many times weaker than Jupiter's?
 Definition
20 times
Term
True or False: Saturn is much colder than Jupiter.
 Definition
True
Term
What is the dramatic difference in the winds of Jupiter and Saturn?
 Definition
The winds of Jupiter form the boundaries for each of the belts and zones, but on Saturn the pattern is not the same. Saturn has fewer such winds, but they are much stronger. The winds at Saturn's equator, for example, are roughly five times faster than the wind at Jupiter's equator.
Term
Three important notes on Saturn's rings
 Definition
1. The rings are made up of billions of ice particles, each in its own orbit around the planet.
2. The gravitational effects of small moons called shepherd satellites can confine some rings in narrow strands or keep the edges of rings sharp.
3. The ring particles are confined to a thin layer in Saturn's equatorial plane by gravity of small moons. The rings of Saturn, and the rings of the other Jovian worlds, are created from and controlled by the planet's moons. Without the moons, there would be no rings.
Term
Describe Titan.
 Definition
Saturn's largest satellite. It's a giant ice moon with a thick atmosphere. Surface is mostly frozen water ice with some methane mixed in.
Term
Why are seasons on Uranus so extreme?
 Definition
Because of it's axial tilt of 97.9 degrees -- Uranus orbits sideways.
Term
True or False: Uranus, like Jupiter and Saturn, has no surface.
 Definition
True
Term
What are the three cloud layers of Uranus?
 Definition
Three cloud layers of ammonia, ammonia hydrosulfide, and water.
Term
Three important notes on the rings of Uranus.
 Definition
1. The rings of Uranus were discovered during an occultation when Uranus crossed in front of a star.
2. The rings are made up of a thin layer of very dark boulders. They are confined by small moons, and except for the outermost rings, they contain little dust.
3. Like the rings of Jupiter and Saturn, the rings around Uranus and Neptune cannot survive for long periods. All the Jovian rings need to be resupplied with material from impact on moons.
Term
How many times bigger is Neptune than the Earth?
 Definition
4 times
Term
Why does Neptune have a blue-green color?
 Definition
Methane in its hydrogen-rich atmosphere absorbs red light
Term
The winds of Neptune
 Definition
Fastest winds in the solar system blow in retrograde motion
Term
The Rings of Neptune
 Definition
1. Similar to those of Uranus but contain more small dust particles that forward-scatter light
2. One of Neptune's moons produces short arcs in the outermost ring, and a similar arc has been found in Saturn's rings
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