Astronomy Chapters 8-12 Test 3

Describe the two theories of planetary ring formation.

1st breakup hypothesis - rings are the remains of a shattered moon‒Comet or asteroid might have collided with the moon breaking it into pieces. ‒Tidal forces then pulled the fragments apart - dispersed into a disk 2nd hypothesis - particles that were unable to form a moon in the first place.•Do not know which explanation holds for any given ring ‒A few rings are relatively young result of breakup•Rings need to be replenished

What are the general features of the surface of Venus? What do the study of craters on Venus tells us about the age of its surface?

75% of surface lowland lava plains Two continents of mountainous terrain The large craters indicate an average surface age between 300 and 600 million years.

What is the general composition and structure of the atmosphere on Venus? How did the greenhouse effect lead to high temperatures on Venus?

96% carbob dioxide, 3.5% nitrogen, little argon, oxygen, and neon(has water vapor). Warmer upper atmosphere does not allow precipitation, atmosphere holds more water vapor Water vapor + CO2 -greenhouse gases -temperature increases further Higher temperature Increased evaporation

How does the thick atmosphere of Titan make bodies of liquid on its surface possible?

About same diameter, mass, and density as Callisto or Ganymede•Similar composition - about ½ ice and ½ rock. •Thick atmosphere and lakes, rivers and falling rain of hydrocarbons - CH4 and C2H6 Surface pressure: 1.6 bar•Surface temperature: 94 K (-290o F)•CH4 and C2H6 can condense and lead to rain•Many organic compounds - basis of life

What is the general composition of the atmosphere on Mars?

Atmosphere < 1% of EarthComposed of CO2 (95%), N2 (3%), Ar (2%) argon, trace H2O, and trace O2Similar proportions to Venus High speeds winds - less force than on Earth Wind - loft fine dust particles - planet-wide dust stormsNo surface water - wind erosion major role in sculpting the Martian surface

Explain the ways that life and geological activity have influenced the evolution of the atmosphere.

Blue-green algae - takes in CO2 and releases O2 as a waste product - photosynthesis•Earth's atmosphere lacked abundant O2 until about 2 billion years ago•Chemical reactions with Earth's crust removed O2•Growth in the plant population Increased O2 Earth's O3 layer protects against UV•Allowed colonization of the land

Discuss the atmospheric composition and the cloud formation and atmospheric structure of the gas giants

CH4 and NH3 identified in the visible spectrum•H and He detected by Voyager in the far-infrared spectrum•H, He dominant•Saturn has less He due to precipitation •Different gases freeze at different temperatures•Jupiter and Saturn: methane remains a gas, but ammonia can condense and freeze. •Primary clouds - frozen ammonia crystals.•Jupiter's clouds are vivid•Saturn's more subdued Uranus-Featureless from ultraviolet to the infrared •Calculations - atmosphere should resemble Jupiter and Saturn•Upper clouds - methane rather than ammonia•Absence of internal heat source suppresses up-and-down movement very stable atmosphere with little visible structure. Neptune-Upper atmosphere - less haze than UranusInternal heat source - convection currents some cloud structure

Compare the major rings of Saturn and explain the role of the moon Enceladus in the formation of the E ring.

Cassini found that much of the material for Saturn's E-ring—a diffuse ring outside the bright, main rings—comes from the moon Enceladus, which is venting icy particles and gas into space as it orbits Saturn. the rings are mostly made of pieces of water ice of different sizes Cassini division, Enke gap, Keeler gap

Describe the causes and effects of the atmospheric greenhouse effect and global warming.

Cause- Coal burned in power stations contains carbon which combines with oxygen in the atmosphere to form carbon dioxide. The man-made (or anthropogenic) component of the greenhouse effect is caused by man's activities that emit greenhouse gases to the atmosphere. The most important of these is the burning of fossil fuels. effect- The greenhouse effect is the process by which radiation from a planet's atmosphere warms the planet's surface to a temperature above what it would be without its atmosphere. •Human-made CFCs destroy ozone, reducing protection from ultraviolet radiation.•Human activity is driving many species to extinction.•Human use of fossil fuels produces greenhouse gases that can cause global warming. •Storms more numerous and intense•Rising ocean levels; melting glaciers•Uncertain effects on food production, availability of fresh water•Potential for social unrest

Explain what we have learned from examination of meteorites from Mars.

Chemicals result from the formation of minerals, deposited from fluids during weathering processes on mars Unique evidence of water weathering on the planet's surface. There are signs of elements being carried into cracks in the rocks by water or fluid

Describe the components of Earth's interior and explain how scientists determined its structure.

Core, mantle, and crust are divisions based on composition. The crust makes up less than 1 percent of Earth by mass, consisting of oceanic crust and continental crust is often more felsic rock. The mantle is hot and represents about 68 percent of Earth's mass. Finally, the core is mostly iron metal. Scientists have been able to distinguish the layers of the Earth that are made of different materials that transmit waves at different speeds. Based on seismic observations

How do crater counts to determine relative ages of lunar landforms?

Crater counting is a method for estimating the age of a planet's surface. The method is based upon the assumptions that when a piece of planetary surface is new, then it has no impact craters; impact craters accumulate after that at a rate that is assumed known. Consequently, counting how many craters of various sizes there are in a given area allows determining how long they have accumulated and, consequently, how long ago the surface has forme

What are the characteristics of the giant planets' magnetic fields and how were they discovered?

Each planets has strong magnetic field‒Generated by electric currents in rapidly spinning interior•Magnetospheres - regions where planet's magnetic field dominates over interplanetary magnetic field.‒largest features, extending millions of km into space.•Jupiter emits radio waves - high-speed electrons accelerated in a magnetic field•Saturn, Uranus and Neptune have magnetic fields - not as strong•Io's volcanoes send charged particles into Jupiter's magnetosphere

Why are impact craters less common on Earth compared with other planets and moons?

Earth has tectonic plates. This means over time, even the largest crater will eventually get sucked under into the melting pot of the mantle, resulting in it's disappearance at some point. Earth has water and an atmosphere. Water and air mean erosion, and erosion means no long lasting craters. The moon has a very thin atmosphere that doesn't really erode anything. Earth's atmosphere also means many incoming objects burn up on entry and explode above the surface. See the Tunguska event, or the recent explosion at Chelyabinsk. They caused damage to stuff above ground, but the Earth itself was relatively unscathed. Other planets do not have all of these characteristics

Differentiate between Earth's various atmospheric layers and describe the chemical composition of our atmosphere.

Earth's atmosphere is divided into five main layers: the exosphere, the thermosphere, the mesosphere, the stratosphere and the troposphere. The atmosphere thins out in each higher layer until the gases dissipate in space. Nitrogen — 78 percent Oxygen — 21 percent Argon — 0.93 percent Carbon dioxide — 0.04 percent

How did a massive impact change the conditions for life on Earth, leading to the extinction of the dinosaurs?

For months, scientists conclude, dense clouds of dust blocked the sun's rays, darkening and chilling Earth to deadly levels for most plants and, in turn, many animals. Then, when the dust finally settled, greenhouse gases created by the impact caused temperatures to skyrocket above pre-impact levels. In just a few years, according to this hypothesis, these frigid and sweltering climatic extremes caused the extinction of not just the dinosaurs, but of up to 70 percent of all plants and animals living at the time.

Provide an overview of the composition of the giant planets as summarize by the missions sent to the gas giants

Galileo spacecraft launched in 1989 and arrived at Jupiter in 1995•Deployed probe - studies of outer atmospheric layers•Descended 95 miles (153 km), collected 58 min of data•Jupiter's atmosphere drier•Few clouds, and lightning only in the distance•Probe had entered a "hot spot."•Winds of 450 mph (724 km/hr)•Probe finally vaporized by intense heat of atmosphere.

Describe the major features we can observe and the geologic activity of each of the Galilean moons.

Ganymede: •Great deal of cratering•About ¼ of surface old and heavily cratered as that of Callisto•Rest formed more recently. Younger terrain formed by tectonic and volcanic forces•Crust cracked, flooding craters with water from the interior. •Mountain ranges formed from compression of the crust, long ridges, parallel valleys a few kilometers apart.•In some areas, older impact craters were split and pulled apart.•Tidal forces from Jupiter may have heated its interior and triggered major convulsions on its crust. Europa: •Europa and Io rocky objects•Jupiter radiated infrared energy after formation•Ice near Jupiter vaporized•Surface layer of ice•Few impact craters - surface continually renewed•Internal heating generated by tidal friction Io: Same size and density as our Moon - similar history?•Not dead cratered world - highest level of volcanism in the solar system•Volcanism - hot silicate lava•Lava encounters frozen deposits of sulfur and sulfur dioxide•When heated eruptive plumes larger than terrestrial volcanoes•100 recently active volcanoes•Change the surface

Describe the top three early hypotheses of the formation of the Moon.

Giant impact- the Moon formed out of the debris left over from a collision between Earth and an astronomical body the size of Mars, approximately 4.5 billion years ago Co-formation- n 2012, researcher Robin Canup, of the Southwest Research Institute in Texas, proposed that Earth and the moon formed at the same time when two massive objects five times the size of Mars crashed into each other. "After colliding, the two similar-sized bodies then re-collided, forming an early Earth surrounded by a disk of material that combined to form the moon," NASA said. "The re-collision and subsequent merger left the two bodies with the similar chemical compositions seen today. Capture theory-Perhaps Earth's gravity snagged a passing body, as happened with other moons in the solar system, such as the Martian moons of Phobos and Deimos. Under the capture theory, a rocky body formed elsewhere in the solar system could have been drawn into orbit around Earth. The capture theory would explain the differences in the composition of Earth and its moon.

Describe the various features found on the surface of Mars.

Has the largest volcano in the solar system(Olympus mons) Vast canyonlands Iron oxide & clays; volcanic rocks, Lowland terrain to flooded areas

Describe what we learned from the landing on Titan with the Huygens probe.

Huygens probe landed on Titan's surface in 2005.•Surface pressure: 1.6 bar•Surface temperature: 94 K (-290o F)•CH4 and C2H6 can condense and lead to rain•Many organic compounds - basis of life

Outline the origins and subsequent diversity of life on Earth.

In addition to chemical and fossil evidence, scientists use the study of the genetic code •By looking gene sequences of many organisms, life on Earth is descended from a common ancestor Atmosphere of early Earth - CO2, CH4, but no O2•With no O2 chemical reactions are possible amino acids, proteins, and other building blocks of life. •These building blocks were available very early and would have combined to make living organisms.

What is the basic composition of each Jovian planet's ring system?

Jupiter- 79 known moons and faint ring (12 just found) Saturn- Rings - broad and flat, some gaps‒Not solid, collection of icy fragments ‒Ring particles - water ice Uranus - 11 rings and 27 known moons. Rings are narrow ribbons of dark material with broad gaps in between. Neptune- The rings are narrow and faint. ‒Composed of dark materials like Uranus

What is the basic physical characteristics, general appearance, rotation, composition and structure of Jupiter, Saturn, Uranus, and Neptune?

Jupiter- rotation: 9.9 hours period: 11.9 years 318 times more massive than earth Saturn- rotation: 10.7 hours period: 29.5 years 95 as massive as earth Uppermost clouds of Jupiter and Saturn composed of ammonia crystal Jupiter and Saturn•Mostly H and He gas Uranus- rotation: 17.2 hours, period 84.1 years, 14 times more massive than earth no obvious cloud layer - featureless haze Neptune- rotation: 16.2 hours period: 164.8 years, 17 times more massive than earth upper clouds methane Uranus and Neptune•Mostly hydrogen compounds: H2O, CH4, NH3•Some H, He, and rock

What is the composition and structure of the Moon?

Like the Earth, the moon boasts a crust, mantle and core. Deep inside of its interior, the moon may have a solid iron core surrounded by a softer, somewhat molten liquid iron outer core. The average composition of the lunar surface by weight is roughly 43 percent oxygen, 20 percent silicon, 19 percent magnesium, 10 percent iron, 3 percent calcium, 3 percent aluminum, 0.42 percent chromium, 0.18 percent titanium and 0.12 percent manganese.

What evidence has been discovered for the presence of water in the history of Mars?

Mars contains polar caps There is evaporating ice on Mars Dried river beds Frozen water also lies beneath the surface. Scientists discovered a slab of ice as large as California and Texas combined in the region between the equator and north pole of the Red Planet.

Describe the history of the lunar surface.

Once lunar samples were brought back by the Apollo astronauts, the radioactive dating techniques that had been developed for Earth were applied to them. The solidification ages of the samples ranged from about 3.3 to 4.4 billion years old, substantially older than most of the rocks on Earth. For comparison, as we saw in the chapter on Earth, Moon, and Sky, both Earth and the Moon were formed between 4.5 and 4.6 billion years ago.

Compare the volcanoes and canyons on Mars with those of Earth

Placed on Earth, the base of Olympus Mons would completely cover the state of Missouri; the caldera, the circular opening at the top, is 65 kilometers across, about the size of Los Angeles. Among the most spectacular tectonic features on Mars are the canyons called the Valles Marineris (or Mariner Valleys, named after Mariner 9, which first revealed them to us), which are shown in Figure 7. They extend for about 5000 kilometers (nearly a quarter of the way around Mars) along the slopes of the Tharsis bulge. If it were on Earth, this canyon system would stretch all the way from Los Angeles to Washington, DC. The main canyon is about 7 kilometers deep and up to 100 kilometers wide, large enough for the Grand Canyon of the Colorado River to fit comfortably into one of its side canyons.

Explain the theory of plate tectonics.

Plate tectonics is the theory that Earth's outer shell is divided into several plates that glide over the mantle, the rocky inner layer above the core. The plates act like a hard and rigid shell compared to Earth's mantle.

Name the major moons of each of the Jovian planets.

Saturn- Titan, encladus Neptune- Triton, Jupiter- Ganymede, Europa, Io Callisto Uranus- Umbriel

How is ring structure affected by the presence of moons?

Small moons imbedded in rings produce waves in the surrounding ring material•Saturn's F Ring bounded by the orbits of two moons, called Pandora and Prometheus‒Referred to as shepherd moons - their gravitation "shepherds" the ring particles - keep them confined to a narrow ribbon

Compare the planetary evolution of Venus, Earth, and Mars.

Started with about same chemical mix (silicates and metals)•Evolutionary paths diverged ‒Venus - hot, dry‒Mars - cold, dry•Possible reasons:‒Size‒Rotation‒Magnetic field ‒Distance from Sun

What is the origin, size, and extent of Earth's magnetic field?

The Earth's magnetic field is believed to be generated by electric currents in the conductive iron alloys of its core, created by convection currents due to heat escaping from the core. On the dayside of Earth, the magnetic field is significantly compressed by the solar wind to a distance of approximately 65,000 kilometers (40,000 mi). Earth's bow shock is about 17 kilometers (11 mi) thick and located about 90,000 kilometers (56,000 mi) from Earth.

What are the primary types of rock that constitute Earth's crust?

The crust of the Earth is composed of a great variety of igneous, metamorphic, and sedimentary rocks. The upper part of the mantle is composed mostly of peridotite, a rock denser than rocks common in the overlying crust.

Describe how impacts have influenced the evolution of life on Earth.

The fact that the oldest surviving microbes on Earth are thermophiles (adapted to very high temperatures) can also be explained by such large impacts. An impact that was just a bit too small to sterilize the planet would still have destroyed anything that lived in what we consider "normal" environments, and only the creatures adapted to high temperatures would survive. Thus, the oldest surviving terrestrial lifeforms are probably the remnants of a sort of evolutionary bottleneck caused by repeated large impacts early in the planet's history.

What are some distinguishing characteristics of Pluto's large moon Charon?

The inset shows an area about 390 kilometers from top to bottom. Near the top left is an intriguing feature—what appears to be a mountain in the middle of a depression or moat.

Differentiate between the major surface features of the Moon.

The moon's landforms are byproducts of meteor impacts and volcanic activity. The lunar surface can be divided into two main regions, the highlands and the maria. The highlands make up roughly 83 percent of the moon's surface, whereas the maria make up about 17 percent of its surface. Both of these regions have a characteristic density of craters from meteor impacts.

Describe the topography and features of Mercury's surface.

The planet Mercury looks a little bit like Earth's moon. Like our Moon, Mercury's surface is covered with craters caused by space rock impacts. e topography of Mercury's northern hemisphere is mapped in great detail from MESSENGER data. The lowest regions are shown in purple and blue, and the highest regions are shown in red. The difference in elevation between the lowest and highest regions shown here is roughly 10 kilometers. The permanently shadowed low-lying craters near the north pole contain radar-bright water ice.

What is the relationship between Mercury's orbit and rotation?

The rotation of Mercury is a little strange to Earth bound creatures. It rotates on its axis very slowly compared to its orbital period. One rotation takes 56.85 Earth days, while one orbital period only takes 88 Earth days. This means that a single day on Mercury last about 0.646 times as long as a single year. The planet's equatorial rotational speed is 10.892 km/h. These periods are given in solar days. In sidereal days Mercury rotates every 58.647 days and orbits twice during every three rotations.

Why is the surface of Venus inhospitable to human life?

The successful Venera landers of the 1970s found themselves on an extraordinarily inhospitable planet, with a surface pressure of 90 bars and a temperature hot enough to melt lead and zinc

How do tidal forces generate the geological activity we see on Europa and Io?

The tidal forces cause them to flex and stretch because its orbit is an ellipse, rather than a circle, and the tide is much higher when the moon is close to Jupiter than when it is farther away. In addition, the flexing could produce volcanic activity from the rocky interior, as on the neighboring moon Io. The tidal forces also cause Europa's icy outer shell to flex, likely causing the long, linear cracks seen in images of its surface.

How do the rings of Uranus and Neptune differ in composition and appearance from the rings of Saturn?

Uranus' and Neptune's rings are narrow and black(hardly visible) made of dark substance, where Saturn is visible and comped of water ice.

What is the internal heat sources of each of the giant planets? How are they different?

Uranus- n0/ little energy source(gets most of it's energy from the sun). Jupiter has the largest internal heat source. Most of the internal energy of Jupiter is primordial heat, left over from the formation of the planet 4.5 billon years ago. Saturn has an internal heat source half as large as Jupiter:The source of this energy is the separation of helium from hydrogen in Saturn's interior. In the liquid hydrogen mantle, the heavier helium forms droplets that sink toward the core, releasing gravitational energy. In effect, Saturn is still differentiating—letting lighter material rise and heavier material fall. Neptune has a very small energy source.

Compare the basic physical properties of Earth, Mars, and Venus, including their orbits.

Venus appears very bright, sometimes it appears as morning star or evening star. Earth has a blue marble appearance, with white clouds, mars is distinctly reddish brown. Orbital periods: Earth- 365 Mars-687, Venus 225

Compare tectonic activity and volcanoes on Venus with those of Earth.

Venus does have tectonic activity: faults, folds, volcanoes, mountains, and rift valleys. However, it does not have global tectonics as there is on Earth—plate tectonics. This is thought to be due to the fact that Venus is hot and dry. To have true plate tectonics, you need to have subduction zones so that one plate can ride over the other. This happens on Earth, but not on Venus.

What features do we observe on the surface of Triton when Voyager 2 flew by?

Voyager 2 took pictures of "several geyser-like volcanic vents that were apparently spewing nitrogen gas laced with extremely fine, dark particles," according to NASA. The agency estimates the particles go as high as 5 miles (8 kilometers) before flowing downwind and striking the surface.

Summarize the evidence for and against the possibility of life on Mars.

Water on Mars in the past =life?•Viking lander - no life detected• No trace of organic material• Return of sedimentary rock to be analyzed for life

What is the difference between weather and climate?

Weather is the day-to-day state of the atmosphere, and its short-term variation in minutes to weeks. People generally think of weather as the combination of temperature, humidity, precipitation, cloudiness, visibility, and wind. ... Climate is the weather of a place averaged over a period of time, often 30 years.

What have we learned from both manned and robotic lunar exploration?

composition of other planets, if they have atmospheres, what their surfaces are composed of, moons of different planets etc.

Describe information about Pluto's surface deduced from the New Horizons images

his New Horizons image clearly shows the variety of terrains on Pluto. The dark area in the lower left is covered with impact craters, while the large light area in the center and lower right is a flat basin devoid of craters.

What is the difference between rift and subduction zones?

rift- A large area of the earth in which plates of the earth's crust are moving away from each other, forming an extensive system of fractures and faults. subduction- Subduction is a geological process that takes place at convergent boundaries of tectonic plates where one plate moves under another and is forced to sink due to gravity into the mantle.

Describe Mercury's structure and composition.

structure- Like Earth, Mercury has a crust, mantle and core. At the heart of Mercury is it's core. This is a ball of liquid iron and other metals that measures approximately 3,600 km across. Considering the fact that Mercury itself is only 4,879.4 km across, the planet's core accounts for 42% of its volume. Compare this to the Earth's core, which only accounts for 17% of our planet's volume. Astronomers only learned recently that Mercury's core is liquid, and not solid as originally theorized. They did this by studying how radio signals bounce off the surface of Mercury. They found that wobbles in the planet's rotation matched predictions only if Mercury's core was liquid. Surrounding the core of Mercury is the mantle. Similar to Earth, this mantle consists of silicates, but it only measures 500-700 km thick. Compared this to the Earth's mantle, which accounts for most of the volume of the planet. And surrounding Mercury's mantle is its crust. A region of the planet the measures between 100-300 km thick. Unlike the Earth's crust, Mercury's crust has no plate tectonics, so it doesn't have plates that float above the interior of Mercury. Without these plate tectonics, even impact craters billions of years old are preserved on the planet's surface. comp- Astronomers have estimated that the Mercury composition is made up of approximately 70% metals and 30% silicate material. In fact, it's only slightly less dense than the Earth, with 5.43 g/cm3.

Summarize the current "giant impact" concept of how the Moon formed.

the Moon formed out of the debris left over from a collision between Earth and an astronomical body the size of Mars, approximately 4.5 billion years ago

Characterize the wind and weather patterns and the scale and longevity of storms onthe giant planets.

•Atmospheres have regions of high and low pressure •Air flows between these regions wind patterns•Changing cloud patterns measure wind speeds and track circulation - horizontal (east-west) patterns•Except Uranus - vertical convection Jupiter's speeds exceeding 400 mph (620 kph) in wide bands of latitude. Winds in adjacent bands blow in opposite directions. (great red spot and red sport jr. found in 1800's Great red spot is a high pressure storm Late 1800s storm as large as 25,500 miles on its long axis. Neptune's great dark spot 8,100 × 4,100 mi; wind speed 1,500 mi/hr

Summarize our ideas about the origin and evolution of Mercury.

•Mercury is composed mostly of metal. •Should have same ratio of metal to silicate as on Earth or Venus. •How did it lose so much of its rocky material?•Mercury may have experienced giant impacts early•Torn away a fraction of its mantle and crust, leaving large iron core.

How do the orbital characteristics of Pluto compare with those of the planets?

•Not like terrestrial or Jovian planets•r = 2.0 g/cm3 - comet like•Eccentric orbit inclined to ecliptic•5 moons