ASTRONOMY FINAL HW

What does an asteroid impact probability of 99% mean?

It means there is a 1% chance the asteroid will miss Earth.

Given that the fossil record provides the key evidence for evolution, what is the importance of Darwin's theory of evolution?

It represents our understanding of the process by which evolution occurs.

The asteroid belt lies between the orbits of

Mars and Jupiter.

What fraction of the original uranium-235 should be left after 3.5 billion years?

1/32

About how old is the solar system?

4.5 billion years

Make a prediction: If the rise in carbon dioxide concentration continues at its current pace, the concentration in the year 2050 will be about _____ parts per million.

460

Why does the rotation curve for the solar system show speeds that become slower with increasing distance from the Sun?

Because the Sun contains most of the mass of the solar system

Why didn't one form in our solar system?

Because the nebula must have dispersed shortly after the formation of our jovian planets.

How would the plot change if the planet were more massive (but remained at the same orbital distance)?

The peaks and valleys would get significantly larger (greater positive and negative velocities) because of larger gravitational tugs.

We cannot see tidal forces or tidal heating; rather, we predict that they must occur based on the orbital characteristics of the moons. What observational evidence confirms that tidal heating is important on Io?

active volcanoes on Io

Where would you expect terrestrial planets to form in the solar nebula?

anywhere between 0.3 AU and the frost line

Saturn's rings

are continually supplied by impacts with small moons.

Which method could detect a planet in an orbit that is face-on to the Earth?

astrometric method

You have found that Planet Z should have active tectonics and volcanism and an atmosphere produced by volcanic outgassing. What single factor explains why the planet should have these characteristics?

has a large size for a terrestrial planet.

How does the habitable zone around a star of spectral type G compare to that around a star of spectral type M?

it is large

Which one of the following can the transit method tell us about a planet?

its size

Which color in the right image indicates regions with the highest temperature?

white

Suppose sulfur dioxide currently makes up 1% of Io's mass. When will Io run out of this gas at the current loss rate? Express your answer using one significant figure.

30 Billion Years

A measument of 700.1 seconds has ____ significant digits

4

Explosions like this happen once every

Century

Io is shown in the figure below. (Left: approximate colors of Io in visible light; black spots are volcanoes that are still active or have recently gone inactive. Right: infrared thermal emission from Io; the bright spots are active volcanoes.) What do the colors represent in the right image?

the intensity of the infrared light

How often do objects big enough to create craters like the Meteor Crater impact Earth?

about once every ten thousand years

Leftover ice-rich planetesimals are called

comets

When you zoom in on the section labeled "Southern Highlands," which geologic processes are most clearly evident?

impact cratering and erosion

As the mass of the central star increases, the distance to the habitable zone __________ and the size (width) of the habitable zone __________. Select from the choices in the format first blank / second blank.

increases / increases

Is this mass accumulation significant for Earth as a planet?

insignificant

Listed following are statements that, based on our current theory of solar system formation, apply either to the formation of terrestrial planets or of Jovian planets, but not both. Match these to the appropriate category.

*Terrestrial Planets* -accerted from plentesimals of rock and metal -surfaces dramatically altered during the heavy bombardment *Jovian Planets* -formed in regions cold enough for water to freeze -large moons formed in surrounding disk of meaterial -accreted from icy planetesimals that are now Oort cloud comets -formed in a region of the solar system with lower orbital speeds

Use standard rounding rules to round the number 627.3051 to complete the statements below. You may wish to watch the video Precision and Significant Digits, Part 2. Drag the appropriate labels to their respective targets. You may use the same label more than once, and not all labels will be used.

-627.3051 rounded to the nearest 100 is 600 -627.3051 rounded to the nearest 10 is 630 -627.3051 rounded to 4 significant digits is 627.3 -627.3051 rounded to 1 significant digit is 600 -627.3051 rounded to the nearest 0.01 is 627.31 -627.3051 rounded to the nearest 0.1 is 627.3

Study the features relating to the first characteristic (orderly motions); click on the inner or outer solar system to see the planets in motion, then scroll over the planets to see diagrams of their axis tilts. Which of the following correctly describe patterns of motion in the solar system?

-All the planets (not counting Pluto) orbit the Sun in nearly the same plane. -All the planets (not counting Pluto) have nearly circular orbits. -Planets closer to the Sun move around their orbits at higher speed than planets farther from the Sun.

Consider again the same set of five stars. This time, rank the stars based on the size (width) of their habitable zones, from smallest to largest.

-Barnards star (M4) -61 cygni A (K5) -Alpha Centauri A (G2) -Sirius (A1) -Spica (B1)

Imagine that each of the five stars is orbited by a terrestrial planet at a distance of 1 AU (Earth's distance from the Sun). Rank the stars based on the planet's expected surface temperature (not including any greenhouse effect), from lowest to highest.

-Barnards star (M4) -61 cygni A (K5) -Alpha Centauri A (G2) -Sirius (A1) -Spica (B1)

Listed below are the names, spectral types (in parentheses), and approximate masses of several nearby main-sequence stars. Rank the stars based on the distances to their habitable zones (from the central star), from shortest to longest.

-Barnards star (M4) -61 cygni A (K5) -Alpha Centauri A (G2) -Sirius (A1) -Spica (B1)

The dwarf planet Eris was discovered in 2005, orbiting the Sun at an average distance about twice that of Pluto. In which of the following ways do Pluto and Eris differ from the terrestrial and jovian planets in our solar system?

-Both Pluto and Eris are smaller than any of the terrestrial planets. -Both Pluto and Eris travel in more elliptical orbits than any of the terrestrial or jovian planets. -Both Pluto and Eris are less massive than any of the terrestrial or jovian planets

Listed below are several geological and biological events in Earth's history. Rank the events in the order in which they occurred, from first to last.

-Giant impact forms moon -End of heavy bombardment -early life -oxygen buildup in the atmosphere -animals colonize land -earliest mammals -dinos go extinct -ealiest humans

Based on the nebular theory as it explains our own solar system, which of the following should we expect to be true for other star systems?

-Jovian planets always form farther from their star than terrestrial planets -Planetary systems should be common. -Many extrasolar planets should fall into the terrestrial or jovian categories. -Planetary systems should generally have all planets orbiting in nearly the same plane.

Assume that the migration hypothesis is the correct explanation for the hot Jupiters. In that case, the revised nebular theory looks just like the old theory, except that it now allows for the possibility of migration. Which of the following statements are consistent with this revised theory?

-Jovian planets always form in the cold, outer regions of their star system. -Terrestrial planets always form in the warm, inner regions of their star system. -Jovian planets can migrate inward and disrupt the orbits of terrestrial planets.

Now consider the second major characteristic (two types of planets). Which of the following statements are true?

-Jovian planets have more moons than terrestrial planets. -Jovian planets are larger in mass than terrestrial planets. -Jovian planets orbit farther from the Sun than terrestrial planets. -Jovian planets are larger in size than terrestrial planets.

Although the data show only a correlation between the carbon dioxide concentration and the global average temperature, scientists have other reasons to think that a rise in the carbon dioxide concentration actually causes a rise in the global average temperature. All of the following statements are true. Which statements lend support to the idea that carbon dioxide is a cause of planetary warming?

-Models of Earth's climate that include recent increases in the carbon dioxide concentration match observed temperature increases better than those that do not include it. -We understand the physical mechanism of the greenhouse effect, through which carbon dioxide can increase a planet's temperature. -Models of the greenhouse effect successfully predict the temperatures of Venus and Mars from their atmospheric carbon dioxide amounts.

All the following statements are true. Which of them are considered to be "exceptions" to the general trends described by the first three major characteristics of the solar system?

-Our Moon has a diameter more than 1/4 the diameter of Earth. -Uranus rotates with an axis tilt that lies nearly in the ecliptic plane -Venus rotates in a direction opposite to the rotation of the other terrestrial planets.

The theory of evolution by natural selection gained rapid acceptance among biologists after Darwin published it in 1859, in part because it was so successful in explaining what we see in the fossil record. The theory of evolution has gained even further support since that time, because it has successfully passed many other observational tests. Which of the following statements represent successful tests of the theory of evolution by natural selection?

-Over time, bacteria tend to acquire resistance to antibiotic drugs. -Genetic comparisons show that the DNA of closely related species is more similar than that of more distantly related species. -Species often show unique adaptations that are suited to the specific environment in which they live and might be detrimental in other environments.

How can scientists account for the fact that extrasolar planets seem to come in a wider range of types than the planets of our solar system?

-The differences result from migration, which in turn may result from a postponement of the clearing of the solar nebula. -Not all nebulas are alike - _some richer in planet-forming elements than others, and some poorer.

Based on Planet Z's size, orbital distance, and rotation rate, which of the following properties is it likely to have?

-an atmosphere produced by outgassing -active volcanos -active tectonics

List the following events in the order in which they occurred, from first to last.

-first life on Earth -first time there is significant oxygen in Earth's atmosphere -earliest animals -earliest plants living on land -earliest mammals -impact causes extinction of dinosaurs -earliest humans

The solar system contains vast numbers of small bodies, which we call asteroids when they are rocky and comets when they are icy. These small bodies are concentrated in the region(s) of the solar system that we call __________.

-the asteroid belt -the Oort cloud -the Kuiper belt

Thinking about the units of a problem can often help you devise a strategy for solving it. Consider the types of units that go with the following equations, then decide which equations are valid statements.

-time=distance/speed -speed=distance/time -distance=speed×time

Earth's temperature remains fairly steady, which means that Earth must return nearly the same amount of energy to space that it receives from the Sun. In what forms does Earth return most of this energy to space?

-visible light reflected by clouds -infrared light emitted by the surface and atmosphere -visible light reflected by the surface

At this rate, what fraction of its mass would Io lose in 4.5 billion years? Express your answer using two significant figures.

0.16%

A measument of 0.0005 microgram has _____ significant digit

1

A measurment of 200,000 centimeters has _____ significant digits

1

A measurment of 700 seconds has ____ significant digits

1

1. The largest moon in the solar system is ______. 2. The jovian moon with the most geologically active surface is ___. 3. Strong evidence both from surface features and magnetic field data support the existence of a subsurface ocean on ______. 4. _______ responsible for the tremendous volcanic activity on Io. 5. ________ the most distant of Jupiter's four Galilean moons. 6. The fact that Europa orbits Jupiter twice for every one orbit of Ganymede is an example of a(n) __________.

1. Ganymede 2. Io 3. Europa 4. tidal heatingis 5. Callistois 6. orbital resonance

1. About a trillion comets are thought to be located far, far beyond Pluto in the ______. 2. The bright spherical part of a comet observed when it is close to the Sun is the _______. 3. A comet's __________ stretches directly away from the Sun. 4. A comet's ________ the frozen portion of a comet. 5. Particles ejected from a comet can cause a(n) __________ on Earth. 6. The Kuiper belt extends from about beyond the orbit of Neptune to about twice the distance of Neptune from the Sun.

1. Oort cloud. 2. coma 3. plasma tail 4. nucleusis 5. meteor shower 6. Kuiper belt

1. A massive object can distort the light of more distant objects behind it through the phenomenon that we call gravitational lensing. 2. WIMPs are defined as subatomic particles that have more mass than neutrinos but do not interact with light. 3. The rotation curvesof spiral galaxies provide strong evidence for the existence of dark matter. 4. Matter made from atoms, with nuclei consisting of protons and neutrons, represents what we call ordinary (or baryonic) matter. 5. Models show that the large-scale structure of the universe is better-explained when we include the effects of dark matter along with the effects of luminous matter. 6. Matter consisting of particles that differ from those found in atoms is generally referred to as exotic (or nonbaryonic) matter.

1. gravitational lensing 2. WIMPs 3. rotation 4. ordiarny (or baryonic) 5. large scale structure 6. exotic (or nonbaryonic)

1. High-mass main-sequence stars have a more distant and wider ________ than low-mass stars. 2. Sky surveys looking for radio signals generated by technology are part of the _______. 3. The _______ designed as a way of estimating the number of intelligent civilizations in the Milky Way. 4. The notion that living organisms with advantages that give them greater reproductive success (in some local environment) will survive while others perish is an example of what Darwin _______. 5. One of the key premises for the ________ that living organisms are able to produce far more offspring than their environment can support. 6. The different time periods of the geological time scale are defined by changes in fossils found from those time periods. 7. Incoming ultraviolet light from the Sun can cause a ______ a living organism's DNA that can affect its ability to survive and reproduce.

1. habitable zone 2. search for extraterrestrial intelligence 3. Drake equationis 4. callednatural selection. 5. theory of evolutionis 6. geological time scale 7. Mutation

What is the mass-to-light ratio of the solar system? Express your answer using two significant figures.

1.0 MSun LSun

The mass of the Sun is 1.99×10^30 kilograms and the mass of Earth is 5.97×10^24 kilograms. Therefore, the combined mass of the Sun and Earth is __________.

1.99×10^30 kilograms

By what factor (approximately) was the energy released by the 1908 Siberian event larger than that released by the Chelyabinsk event, according to the article?

10-30

The Meteor Crater in Arizona is about 1.2 kilometers across. According to the graph, about how big was the object that made this crater? (Note: Be sure to read the axis labels carefully.)

100 meters

According to this graph, the minimum size of an object that could cause a mass extinction is a little less than _____.

10km

A book written in 1980 states that the peak of the last ice age occurred 18,000 years ago. Therefore, in 2012, the peak had occurred _____ years ago.

18000

By what factor has your waist size increased? Express your answer using one significant figure.

2

The pressure on your weight-bearing joints depends on how much weight is supported by the surface area of each joint. How has the pressure on your weight-bearing joints changed? Express your answer using one significant figure.

2

Approximately how many times bigger was the 1908 Siberian asteroid than the diameter of the Chelyabinsk asteroid?

2 times

The density of granite is about 2.75 grams per cubic centimeter. Suppose you have a granite countertop for a kitchen that is 1 meter wide, 3 meters long, and 4 centimeters thick. Which of the following equations will give you its mass, in kilograms?

2.75g/cm^3×1m×3m×(100cm/1m)^2×4cm×1 kg/1000 g

Where did the meteor blow up?

20-30 miles above the Earth's surface

What is the mass-to-light ratio of a 1M Sun white dwarf with luminosity 0.005L Sun?

200 MSun LSun

When Mars is on the opposite side of the Sun from Earth, it is about 4.0×10^8km away. How long does it take a radio signal traveling at the speed of light, c=3.00×10^5km/s,to go from Earth to Mars at this time? Be sure to give your answer with the appropriate precision.

22 minutes

If both the Chelyabinsk asteroid and the 1908 Siberian asteroid were traveling at the same speed, how did the kinetic energy of the Chelyabinsk asteroid compare to the 1908 Siberian asteroid? Assume the diameter of the Siberian asteroid was 3 times the diameter of the Chelyabinsk asteroid?

27 times the kinetic energy

Say the diameter of the Siberian asteroid were 3 times that of the Chelyabinsk asteroid, by what factor was its mass larger than that of the Chelyabinsk asteroid?

27 times the mass

The oldest fossil evidence of life dates to about __________ ago.

3.5 to 4 billion years

How much more material will be required for your clothes? (Hint: Clothes cover the surface area of your body.) Express your answer using one significant figure.

4

Using the data in the table Satellites of the Solar System, identify the orbital resonance relationship between Titan and Hyperion. (Hint: If the orbital period of one were 1.5 times the other, we would say that they are in a 3:2 resonance.)

4:3

A measument of 1.0005 micrograms has ____ significant digits

5

A measurment of 2.00000 x 10^5 centimeters has _____ Signoficant digits

6

Dinosaurs went extinct, probably because of an impact, about __________ ago.

65 million years

As you've seen, the nebular theory predicts that a cloud that gives birth to planets should have the shape of a spinning disk. Which observable property of our solar system supports this prediction?

All the planets orbit the Sun in the same direction and in nearly the same plane.

Listed following are several objects in the solar system. Rank these objects from left to right based on their orbital period around the Sun from shortest to longest.

Shortest a typical astroid in the astroid belt a typical Kuiper belt object a typical Oort cloud object Longest

Listed following are four models for the long-term expansion (and possible contraction) of the universe. Rank the models from left to right based on their predictions for the average distance between galaxies five billion years from now, from smallest to largest.

Smallest Distance recollapsing universe critical universe coasting universe accelerating uiverse Largest universe

The following images show Earth and the four jovian planets of our solar system. Rank these planets from left to right based on their size (average equatorial radius), from smallest to largest. (Not to scale.)

Smallest radius Earth Neptune Uranus Saturn Jupiter Largest radius

Listed following are three possible models for the long-term expansion (and possible contraction) of the universe in the absence of dark energy. Rank each model from left to right based on the ratio of its actual mass density to the critical density, from smallest ratio (mass density much smaller than critical density) to largest ratio (mass density much greater than critical density).

Smallest ratio Coasting universe Critical universe Recollapsing universe

Open the Rotation Curve of a Spiral Galaxy animation and click at various distances from the galactic center to create a graph of the galaxy's rotation curve; be sure to start with points very close to the galactic center and continue to well beyond the visible part of the galaxy. Which of the following statements best describes the pattern of the graph?

Starting from the center, speeds at first rise rapidly, and then become nearly constant with increasing distance.

The following images show the four terrestrial planets in our solar system. Rank the planets from left to right based on the strength of the greenhouse effect occurring at their surfaces, from strongest to weakest.

Strongest Venus Earth Mars Weakest

From Parts A though C, you should understand the three major components shown in the composite Bullet Cluster image. Notice that the hot, X-ray-emitting gas (red) is not in the same place as most of the visible galaxies and most of the matter (blue). How do we think the hot gas came to be in a different place from the galaxies and most of the matter?

The Bullet cluster is actually two separate galaxy clusters that have collided, stripping out hot gas in the process.

Like any scientific theory, the theory of evolution is subject to revision or even to being discarded if future observations do not agree with its predictions. Which of the following hypothetical observations (none of which are real) would force us to reconsider the theory of evolution?

The discovery of fossils of human-like primates dating to a time before the earliest dinosaurs existed.

Scientists think it is very unlikely that complex and large forms of life could evolve on planets that orbit stars that are much more massive than the Sun. Why?

The expected lifetime of a massive star is too short to allow for the evolution of complex life

The idea that life evolves through time was first suggested in ancient Greece, and it was favored by at least some scientists of the 18th and 19th centuries even before Charles Darwin proposed the theory of evolution. What is the key observational evidence that supports the idea that life on Earth has evolved through time?

The fossil record, revealed in geological layers of different ages, shows that life on Earth has become more complex over time.

Where did the energy of impact come from?

The kinetic energy of the asteroid was transformed by friction into heat while it passed through the Earth's atmosphere.

Overall, does the nebular theory seem adequate for describing the origins of other planetary systems?

The nebular theory with the added processes of migration and resonances accounts for the basic properties of extrasolar planetary systems.

Consider the planet that causes the stellar motion shown in Plot 2 (be sure you have clicked the "Plot 2" button in the lower window of the animation). What can be said about a different planet orbiting the same star with an orbital period of 500 days?

The planet must be closer to the star.

Consider only the observed patterns of motion in the solar system. Scientifically, which of the following possible conclusions is justified from the patterns of motion alone?

The planets were not each born in a separate, random event.

Which of the following best explains why a higher-mass cluster of galaxies causes light from a distant galaxy to bend more than a lower-mass cluster of galaxies?

The stronger gravity of a larger cluster curves space itself by a greater amount, and light follows the curvature of space.

By comparing the two images, what can you conclude about Io's volcanoes?

There are more black spots in the visible image than bright spots in the infrared image, so many of Ios volcanoes were inactive when the photos were taken.

The discovery of hot Jupiters led scientists to reconsider the nebuar theory. Which of the following best explains why the nebular theory(as it stood before the discoveries of extrasolar planets) had not predicted the existence of hot Jupiters?

There are no hot Jupiters in our solar system.

Notice that the peaks and troughs on the temperature graph occur at the about the same times as peaks and troughs on the carbon dioxide graph. What can we infer from this fact alone?

There is a correlation between the carbon dioxide concentration and the global average temperature.

Look at the average densities of the jovian planets given in Figure 1. Can you identify a trend in jovian planet densities with mass or distance from the Sun?

There is no clear trend in the densities with mass or distance.

According to scientists, the naturally occurring greenhouse effect makes Earth about 31∘C warmer than it would be if there were no greenhouse gases in our atmosphere. How do scientists "know" what Earth's temperature would be without greenhouse gases?

They calculate this temperature from Earth's reflectivity and distance from the Sun.

Which of the following statements best explains why the densities of Uranus and Neptune are higher than that of Saturn, even though Saturn is much more massive?

They have a higher proportion of hydrogen compounds and rock.

Two hypothetical discoveries in Part A deal with moons that, like Earth's moon, are relatively large compared to their planets. Which of the following best explains why finding 1 planet with such a moon is consistent with the nebular theory, while finding 6 planets with such moons is not consistent?

Unusually large moons form in giant impacts, which are relatively rare events.

Which terrestrial world has the most atmospheric gas?

Venus

Are there any exceptions to the rule that planets rotate with small axis tilts and in the same direction as they orbit the Sun?

Venus and Uranus are exceptions.

All of the following statements are true. Which one provides strong observational support for the claim that greenhouse gases make a planet warmer than it would be otherwise?

Venus has a higher average temperature than Mercury.

We now know of many Jupiter-size planets around other stars. Suppose that future observations show that one of these planets has two orbiting moons. What additional information, if any, would we need to decide whether these moons experience tidal heating?

We need to know their orbital periods.

Based solely on an understanding of the greenhouse effect (as displayed in the figure), which one of the following statements is true?

We should expect an increase in the greenhouse gas concentration to lead to global warming.

Study the composite image of the Bullet Cluster, as well as the animations. What do the two large, red-colored regions in the composite image represent?

X-ray emission from hot gas

Based on the observational evidence, is it possible that dark matter doesn't really exist?

Yes, but only if there is something wrong with our current understanding of how gravity should work on large scales.

Can an asteroid be pure metal?

Yes, it must have been the core of a shattered asteroid.

Listed following are four models for the long-term expansion (and possible contraction) of the universe. Rank each model from left to right based on its prediction for the current age of the universe, from youngest to oldest.

Youngest recollapsing universe critical universe coasting universe accelerating universe Oldestest

What does Pluto most resemble?

a comet

In Part A, you found that Planet Z should not have strong winds and violent storms. What single change to Planet Z's characteristics would cause it to have strong winds and violent storms?

a faster rotation rate

Earth was born about 4.5 billion years ago. According to current estimates, approximately how long after Earth's formation did the Moon form?

a few tens of millions of years later.

Examine the visible light image of the Bullet Cluster. What kind of cluster is it?

a galaxy cluster

How big an object causes a typical shooting star?

a grain of sand or a small pebble

A photograph of a cluster of galaxies shows distorted images of galaxies that lie behind it at greater distances. This is an example of what astronomers call:

a gravitational lens.

In Part A, you found that Planet Z should not have polar ice caps or liquid water. What single change to Planet Z's characteristics would allow it to have these things?

a greater distance from its star

In Part A, you found that Planet Z should not have seasons. What single change to Planet Z's characteristics would cause it to have seasons?

a larger axis tilt

Consider a distant galaxy located directly behind a cluster of galaxies, as shown in this interactive figure. As seen from Earth, the gravitationally lensed images of the distant galaxy will appear more widely separated if the intervening cluster of galaxies has __________.

a relatively high mass and is located relatively near Earth.

The theory of evolution is

a scientific theory, meaning that it is backed by extensive evidence.

In general, what kind of terrestrial planet would you expect to have the thickest lithosphere?

a small planet

On the graphs shown, you can identify an ice age by looking for __________.

a trough (bottom of a dip) on the temperature graph

How long does it take the star and planet to complete one orbit around their center of mass?

about 4 days.

How long did the Cambrian explosion last?

about 40 million years

What maximum velocity does the star attain?

about 50 m/s

According to the graph, an object 10 kilometers across hits Earth __________.

about once every 100 million years

According to the graph in (Figure 1) , how frequently do objects the size of comet Tempel 1 strike Earth?

about once every hundred million years

Greenhouse gases in the atmosphere, such as carbon dioxide and water vapor, make Earth warmer than it would be otherwise because these gases __________.

absorb infrared light emitted by the surface

At time A, is the expansion of the universe accelerating, coasting, or decelerating?

accelerating

At time B, is the expansion of the universe accelerating, coasting, or decelerating?

accelerating

Which model is most clearly ruled out by the data on the graph?

accelerating

Which model predicts the largest average distance between galaxies 6 billion years ago?

accelerating

Which of the models predict that galaxies should be getting farther apart now? (Keep in mind that now is located at at time=0years on the graph.)

accelerating coasting critical recollapsing

A tectonic ridge appears to connect points 3a and 3b, crossing several craters. From its appearance, we can conclude that it must have formed

after the area was cratered.

How many of the planets orbit the Sun in the same direction as Earth does?

all

Consider the hypothetical discovery from Part A reading: "A star's 5 terrestrial planets orbit in the opposite direction of its 3 jovian planets." This discovery would be inconsistent with the nebular theory because the theory holds that __________.

all the planets formed in a rotating, disk-shaped nebula

Now, let's turn our attention to rotation curves for orbiting masses which are not rigidly held together like the points on a merry-go-round. The Rotation Curve of the Solar System animation shows the orbits of Mercury, Venus, Earth, and Mars. Click on each of the orbits, and watch the corresponding points appear on the graph below it. If a planet (or asteroid) orbited the Sun at three times the distance of Mars, its orbital speed would be __________.

between one-third and two-thirds the orbital speed of Mars

Which of the following did not occur during the collapse of the solar nebula?

concentrating denser materials nearer the Sun

At time D, is the expansion of the universe accelerating, coasting, or decelerating?

decelerating

A comet entering the inner solar system from afar will __________.

form a coma and some time later form a tail

The two facts from Parts C and D lead to the "inescapable conclusion" that individuals in a population will have unequal reproductive success, so that those whose traits best enable them to survive will leave more offspring. Therefore, in any local environment, over time, __________.

heritable traits that enhance survival will become progressively more common in succeeding generations

The main ingredients of most satellites of the jovian planets are

hydrogen compound ices.

Orbital resonance also gives Europa an elliptical orbit, so it experiences tidal heating, too. However, Europa experiences less tidal heating than Io, because Europa __________ than Io.

is farther from Jupiter

How does this factor compare with the correct estimate derived in Part E?

its about the same

Why is this meteor consider quite different from the 1908 Siberian event?

its images were uploaded to YouTube almost immediately after the event

Our modern theory of solar system formation—the nebular theory—successfully accounts for all the major features of our own solar system. However, when the first hot Jupiters were discovered, their existence seemed inconsistent with the nebular theory because this theory predicts that __________.

jovian planets can form only in the cold, outer regions of a solar system

Saturn's rings are composed of __________.

lots of individual particles of ice and rock

Today, scientists have a theory (the nebular theory) that explains all the major characteristics of the solar system. In science, we expect a theory like this not only to explain the observed characteristics of our solar system but also to __________.

make testable predictions about other solar systems

The amount of energy that would be needed to accelerate a large spaceship to half the speed of light is

more than 2000 times the current annual global energy consumption.

What substances existed as solid flakes within the inner 0.3 AU of the solar system before planets began to form?

none

There are also two large blue-colored regions in the composite image. These blue regions are labeled as "dark matter" based on __________.

observations of gravitational lensing by the cluster

Dark energy has been hypothesized to exist in order to explain:

observations suggesting that the expansion of the universe is accelerating.

A comet's plasma tail always points directly away from the Sun because __________.

of pressure exerted by the fast-moving charged particles in the solar wind

According to current scientific understanding, the idea that the Milky Way Galaxy might be home to a civilization millions of years more advanced than ours is

one reasonable answer to Fermi's paradox.

Some jovian planets give off more energy than they receive because of

ongoing contraction or differentiation.

Which heat source continues to contribute to Earth's internal heat?

radioactive decay

Which model is most clearly ruled out by the data on the graph?

recollapsing

Which of the models predict that galaxies will eventually get closer together in the future?

recollapsing

The jovian planets are thought to have formed as gravity drew hydrogen and helium gas around planetesimals made of __________.

rocks, metals, and ices

What substances were found within the inner 0.3 AU of the solar system before planets began to form?

rocks, metals, hydrogen compounds, hydrogen, and helium, all in gaseous form

Which of a planet's fundamental properties has the greatest effect on its level of volcanic and tectonic activity?

size

Based on what we know about our own solar system, the discovery of hot Jupiters came as a surprise to scientists because these planets are __________.

so close to their stars

The second of the two "undeniable facts" is that individuals in a population of any species vary in many heritable traits (traits passed from parents to offspring), so that no two individuals are exactly alike. This fact is important to understanding evolution because it means that __________.

some individuals possess traits that make them better able than others to compete for food and other resources

Based on current evidence, which of the following is considered a likely candidate for the majority of the dark matter in galaxies?

subatomic particles that we have not yet detected

From Part D, you know that the galaxy's rotation curve is nearly flat, even well beyond the point at which we see any stars in the galaxy. According to the law of gravity as we understand it today, the only explanation for these this flatness is that __________.

substantial amounts of mass must reside at great distances from the galactic center

During the time that a comet passes through the inner solar system, the comet can appear quite bright because __________.

sunlight reflects off the comet's tail and coma

You are dating rocks by their proportions of parent isotope potassium-40 (half-life 1.25 billion years) and daughter isotope argon-40. Find the age for each of the following. A rock that contains equal amounts of potassium-40 and argon-40.

t= 1.25x10^9 years

Which of the following is a reason why early living organisms on Earth could not have survived on the surface?

the lack of an ozone layer

Observations show that interstellar clouds can have almost any shape and, if they are rotating at all, their rotation is not perceptible. However, the nebular theory predicts that a cloud will rotate rapidly once it shrinks to a relatively small size. What physical law explains why a collapsed cloud will rotate rapidly?

the law of conservation of angular momentum

The nebular theory also predicts that the cloud should heat up as it collapses. What physical law explains why it heats up?

the law of conservation of energy

To understand why the galaxy rotation curve in Part D is flat, we must first understand how gravity determines the orbital speeds of stars around the galactic center. Consider any star on a circular orbit around the center of the galaxy. The speed of the star's orbit depends on the star's distance from the galactic center and __________.

the mass of the galaxy that resides within the star's orbit

Which of the following properties can be inferred from the star's orbital period?

the planet's orbital radius

The right image was obtained when only part of Io was in sunlight.Based on the colors, which part of the surface was in sunlight?

the right side

Consider a distant galaxy located directly behind a cluster of galaxies as shown in this interactive figure. Knowing the distance to the cluster of galaxies and the angular separation of the lensed images of the distant galaxy, astronomers can estimate:

the total amount of matter in the cluster of galaxies, including both dark matter and matter in stars

What method has detected the most extrasolar planets so far?

the transit method

The theory of evolution provides a model of how species evolve through time. As described by biologist Stephen Jay Gould (1942-2002), Darwin built his model from "two undeniable facts and an inescapable conclusion." Parts C, D, and E will help you understand this basis for the theory of evolution. The first of the two "undeniable facts" is that any localized population of a species has the potential to produce far more offspring than the local environment can support. This fact is important to understanding evolution because it means that __________.

there is competition for survival among the individuals of the population

Careful measurements show that the hot, X-ray-emitting gas in the Bullet Cluster contains about 7 times as much total mass as all the stars in the cluster's galaxies combined. Therefore, the fact that the most of the gravity is in the blue regions that surrounds the visible galaxies, rather than in the regions with the hot gas, indicates that __________.

there is even more matter surrounding the galaxies than there is in the hot gas

Consider the hypothetical discovery from Part A reading: "Beyond its jovian planets, a star has two ice-rich objects as large as Mars." This discovery is consistent with the nebular theory, because this theory predicts that _________.

this might have happened in our own solar system if it had taken longer for the solar wind to clear the solar nebula

Which detection method was used by the Kepler mission?

transit method

How many of the five terrestrial worlds are considered "geologically dead"?

two

Compare the graph in (Figure 1) to (Figure 2) , which shows the decay of potassium-40. Which element is more radioactive (undergoes radioactive decay more quickly)?

uranium - 235

The average temperature over the past 1000 years has been about 15∘C. From the graphs, you can conclude that Earth's average temperature during the past 800,000 years has __________.

varied between about 7∘C and 19∘C

The energy that warms Earth's surface comes primarily in the form of __________.

visible light from the Sun

Which of the following is a strong greenhouse gas?

water vapor

Dark matter is inferred to exist because:

we can observe its gravitational influence on visible matter.

The major evidence for the idea that the expansion of the universe is accelerating comes from observations of:

white dwarf supernovae.

Fossil evidence suggests that life on Earth arose

within a few hundred million years after Earth formed.

Is it possible to determine the planet's mass from the star's velocity curve?

yes, by measuring both the star's orbital period and its change in velocity over the orbit

How does Berth's density compare to Earth's? Express your answer using one significant figure.

ρBerth = 1 ρEarth

The following images show Earth and the four jovian planets of our solar system. Rank these planets from left to right based on their distance from the Sun, from closest to farthest. (Not to scale.)

Closest Earth Jupiter Satern Uranus Neptune Farthest

Listed following are several objects in the solar system. Rank these objects from left to right based on their distance from the Sun, from closest to farthest.

Closest a typical astroid in the astroid belt a typical kuiper belt object a typical Oort cloud object Farthest

Sort the following hypothetical discoveries into the appropriate bins as follows: -Consistent with theory: The statement describes a discovery that we could reasonably expect to find if the nebular theory is correct. -Not consistent with theory: The statement describes a discovery that would force us to modify or discard the nebular theory.

Consistent with theory: -beyond its jovian planets, a star has two ice-rich objects as large as Mars. -a star has 20 planets -a star is surrounded by a disk of gas but has no planets -of a stars 5 terrestrial planets, 1 has a moon as large Earth's moon. Not consistent with theory: -a stars 4 jovian planets formed in its inner solar system and its 4 terrestrial planets formed farther out -all 6 of a stars terrestrial planets have a moon as large as earths moon. -a stars 5 terrestrial planets orbit in the opposite direction of its 3 jovian planets. -a star has 9 planets but none orbit in close to the same place

As you've learned from Part B, hydrogen and helium gas never condense under conditions found in the solar nebula. The remaining three categories of material in the solar nebula are shown again here. Rank these materials from left to right based on the distance from the Sun at which they could condense into a solid in the solar nebula, from farthest to closest.

Farthest -hydrogen compounds -rock -metals Closest

The following images show four types (wavelengths) of light. Rank these from left to right based on the amount of each that is emitted (as thermal radiation) by Earth's surface, from greatest to least. If you think that two (or more) types should be ranked as equal, drag one on top of the other(s) to show this equality.

Greatest Amount infrared Visible, ultraviolet, X-ray light

In Part A, you found that Earth emits only infrared light. This infrared light can be absorbed by greenhouse gases, such as carbon dioxide and water vapor, in the atmosphere. In fact, all the terrestrial planets emit infrared light from their surfaces. The following images show the four terrestrial planets in our solar system. Rank these planets from left to right based on the total amount of infrared-absorbing greenhouse gases in their atmospheres, from greatest to least.

Greatest greenhouse gas abundance Venus Earth Mars Mercury Least greenhouse gas abundance

In the Drake equation, suppose that the term flife=1/2What would this mean?

Half of the habitable worlds in the galaxy actually have life, while the other half don't.

In what order did Darya Frenn, the blogger, experience the events?

Heat, dot of light flashing by, explosion

The materials that made up the solar nebula can be categorized into the four general types as follows. Rank these materials from left to right based on their abundance in the solar nebula, from highest to lowest.

High abundence -hydrogen and helium gas -hydrogen compounds -rock -metals Lowest abundence

The following images show the four terrestrial planets in our solar system. Rank these planets from left to right based on the atmospheric pressure at the surface, from highest to lowest. (Not to scale)

Highest Prssure Venus Earth Mars Mercury Lowest Pressure

The materials that made up the solar nebula can be categorized into these four general types. Rank these materials from left to right based on the temperature at which each would condense into a solid, from highest to lowest. Note: For a substance that does not condense at all, rank it as very low temperature.

Highest temperature -metals -rock -hydrogen comounds -hydrogen and helium gas Lowest temperature

How do we think hot Jupiters formed?

Hot Jupiters formed beyond the frost line, as in our solar system, and migrated inward due to interaction with the solar nebula.

The solar system has two types of planets, terrestrial and jovian. According to the nebular theory, why did terrestrial planets form in the inner solar system and jovian planets in the outer solar system?

Ices condensed only in the outer solar system, where some icy planetesimals grew large enough to attract gas from the nebula, while only metal and rock condensed in the inner solar system, making terrestrial planets.

As you learned in Part A, Io's elliptical orbit is necessary to its tidal heating. This elliptical orbit, in turn, is a result of the orbital resonance among Io, Europa, and Ganymede. This orbital resonance causes Io to have a more elliptical orbit than it would otherwise, because __________.

Io periodically passes Europa and Ganymede in the same orbital position.

What is unusual about Triton?

It orbits its planet backward

Which describes our understanding of flowing water on Mars?

It was important once, but no longer.

What is the significance of the impact described in this article?

It was the first time astronomers tracked an asteroid before it hit Earth.

If Earth had no atmosphere, how would the asteroid's kinetic energy shortly before it impacted the surface compare to its kinetic energy when it was far away from Earth? (Hint: Think about the law of conservation of energy.)

It would hit the surface with much higher kinetic energy than it had when it was far away.

You find a mysterious rock on the ground and determine that 60% of its uranium-235 has been converted into lead-207. What is the most likely origin of the rock, based on its radiometric age?

It's a volcanic rock nearly a billion years old.

Why is Jupiter denser than Saturn?

Its higher mass and gravity compress its interior.

Based on the leading scientific theory of solar system formation, which of the following statements best explains why Uranus and Neptune have a significantly different composition than Jupiter and Saturn?

Jupiter and Saturn captured more gas from the solar nebula than Uranus and Neptune.

Which of the following best explains why Jupiter's density is higher than Saturn's?

Jupiter is more massive than Saturn.

Which lists the jovian planets in order of increasing distance from the Sun?

Jupiter, Saturn, Uranus, Neptune

Based on current evidence, how common are planetary systems?

Kepler spacecraft had discovered in total several thousand planet candidates during all the time of its operation, most of them are thought to be real planets.

The following images show the four terrestrial planets in our solar system. Rank the planets from left to right based on the amount by which the greenhouse effect increases their surface temperatures, compared to what their temperatures would be without the greenhouse effect, from largest to smallest increase.

Largest increase Venus Earth Mars Mercury Smallest increase

The region around 2b has far fewer craters than the region around 2c. The crater floor at 2a is also flat and smooth, without many smaller craters on it. Why are regions 2a and 2b so smooth?

Lava flows covered craters that once existed in these regions.

The following images show Earth and the four jovian planets of our solar system. Rank these planets from left to right based on their mass, from lowest to highest. (Not to scale.)

Lowest mass Earth Uranus Neptune Saturn Jupiter Highest mass

Why does Neptune appear blue and Jupiter red?

Methane in Neptune's atmosphere absorbs red light.

What is planetary migration, and how may it account for the surprising orbits of many extrasolar planets?

Migration means the planet gradually moves closer to its parent star. Many extrasolar planets are much closer to their stars than we had expected. We think that it is possible for planets to migrate through their disks because of interactions with the gas in the disk. Migration can lead to resonances, which can make orbits elliptical.

What additional data would be most valuable in helping scientists evaluate whether the accelerating model really is the best of the four models?

More observations of very distant white dwarf supernovae

The following images show the four terrestrial planets in our solar system. Rank these planets from left to right based on the total amount of gas in their atmospheres, from most to least. (Not to scale.)

Most Gas Venus Earth Mars Mercury Least Gas

How does your answer change if there are only 150 civilizations instead of 1.10×104?

N2= 3.33×10^9

If a ring particle survived for the age of the solar system, how many collisions would it undergo? Express your answer using one significant figure.

Ncollisions = 8×1012

Listed following are several objects in the solar system. Rank these objects from left to right based on the distance from the Sun at which they are presumed to have formed, from nearest to farthest.

Nearest to Sun a typical asteroid in the asteroid belt a typical Oort cloud object a typical Kuiper belt object Farthest from Sun

Did a large terrestrial planet ever form in the region of the asteroid belt?

No, because Jupiter prevented one from accreting.

As noted in the Introduction, some scientists have proposed that dark matter does not really exist. According to this view, all matter is ordinary (baryonic), but at large distances from matter, gravity does not precisely obey either Newton's or Einstein's theories of gravity. Is this alternative view of gravity consistent with what we observe in the Bullet Cluster? Why or why not?

No. If all matter was ordinary, then the blue region representing the location of most of the matter would line up with the red region representing the hot gas.

The impact of a 100-meter object will not cause "widespread" devastation, but it could still kill millions of people if it struck a major city. In Part C, you found that the probability of such an impact in any single year is only 1 in 1000. Suppose we learn that it has already been 1200 years since the last such impact. What would that tell us?

Nothing; we would still presume that the chance of such an impact during the next year is 1 in 1000.

Using your answers from Part AC, list the following features in order from oldest to youngest.

Oldest Crater 1a the smooth floor of crater 1b the tectonic ridge from 3a to 3b Youngest

Which of the following Mars surface features provides dramatic evidence that volcanism has played a role in shaping the surface of Mars?

Olympus Mons

Suppose that our Sun was cool enough to include Mercury in its habitable zone. Which of the following would be true in that case?

Only Mercury would be in the Sun's habitable zone.

Which have the most elliptical and tilted orbits?

Oort cloud comets

What do we conclude if a planet has few impact craters of any size?

Other geological processes have wiped out craters.

Which of the following statements correctly describes the motion of the particles in Saturn's rings?

Particles in the inner rings orbit Saturn at a faster speed than particles in the outer rings.

Match the planet's positions at points 1, 2, 3, and 4 in the plot with the descriptions below.

Point 1: closest to earth Point 2: headed straight away from Earth Point 3: farthest from earth Point 4: headed straight toward

Match the star's positions at points 1, 2, 3, and 4 in the plot with the descriptions below.

Point 1: farthest from earth Point 2: headed straight toward earth Point 3: closest to earth Point 4: headed straight away from earth

List the following time frames in order by how long they lasted, from the longest one to the shortest one.

Proterozoic eon Hadean eon Paleozoic era Cretaceous period

Which of the following are time frames in which we are living today? More than one may apply.

Quanity period phananerozoic eon Cenozonic era

Label 1a lies on the rim of a large crater, and 1b lies on the rim of a smaller one. Which crater must have formed first?

crater 1a

Estimate comet Tempel 1's diameter, using the scale bar in (Figure 2) . Express your answer to one significant figure and include the appropriate units.

d = 5km

Each data point represents a single white dwarf supernova that has been observed. The data points that appear farthest to the left on the graph represent the white dwarf supernovae that are the __________.

farthest away from us

Planetary orbits in our solar system are:

fairly circular and in the same plane.

For a planet of a particular mass, the astrometric method will detect the largest stellar motion if the planet orbits

farther from its star

Which of the following worlds is not considered a candidate for harboring life?

the moon

Based on the model types shown in the figure above, a planet made almost entirely of hydrogen compounds would be considered a

"water world."

The government in a town of 82,000 people plans to spend $41.5 million this year. Assuming all this money must come from taxes, what is the average number of dollars that the city must collect from each resident?

$510

Estimate the time it would take for Earth to get 0.1% heavier at this rate.

10^14 years

Today, the leading hypothesis for the existence of hot Jupiters is that they formed in their outer solar systems and then migrated inward. Why did this hypothesis gain favor over alternative ideas?

Computer models that simulate planetary formation show that interactions between young planets and other material in the surrounding disk can cause planetary migration.

Which medium-size moon is in a 2:1 resonance with Enceladus?

Dione

Based on this graph, which statement below most accurately describes the impacts we should expect on Earth during the coming year?

Earth will be hit by at least one object a few meters in diameter, along with many smaller objects.

Shown below are the four terrestrial planets of our solar system. Assume that all the planets started out equally hot inside. Rank the planets based on their expected cooling rates, from fastest cooling to slowest cooling.

Fastest cooling Mercury Mars Venus Earth

What would happen if a 1-kilometer object struck the Earth?

It would cause widespread devastation and climate change.

What's unusual about our Moon?

It's surprisingly large relative to the planet it orbits.

Which are thought to have formed farthest from the Sun?

Kuiper belt comets

On average, how many stars would we have to search before we would expect to hear a signal? Assume there are 500 billion stars in the galaxy. Express your answer using one significant figure.

N1= 4.55×10^7

According to the article, how many people died in this shock wave?

No one

Assuming that features you see on Mars are similar to features found on Earth, what would a casual inspection of the interactive photo of Mars lead you to suspect about water on Mars?

Surface water only exists as frozen ice.

Which moon shows evidence of rainfall and erosion by some liquid substance?

Titan

Listed following are characteristics of the atmospheres of Venus, Earth, and Mars. Match each atmospheric characteristic to the appropriate planet.

Venus -sulfuric acid clouds -almost no surface winds -runaway greenhouse effect Earth -atmosphere composed primarily of nitrogen -ultraviolet-absorbing stratosphere Mars extremely low density atmosphere globa dust storms

Which region of the early universe was most likely to become a galaxy?

a region whose matter density was higher than average

What is the probability that an object 100 meters in diameter will hit Earth during the coming year?

about 1 in 1000

When did the heavy bombardment end?

between about 3.8 and 4.0 billion years ago

Strong evidence for the existence of dark matter comes from observations of:

clusters of galaxies.

At time C, is the expansion of the universe accelerating, coasting, or decelerating?

coasting

About how often does a 1-kilometer object strike the Earth?

every million years

The composition of the solar nebula was 98%

hydrogen and helium

What is Jupiter's main ingredient?

hydrogen and helium

Plants and animals are

just two small branches of the diverse "tree of life" on Earth.

Consider an object twice the size of Comet Tempel 1. What kind of damage would this object cause if it hit our planet?

mass extinction

Compared to terrestrial planets, jovian planets are __________.

more massive and lower in average density

Jupiter nudges the asteroids through the influence of

orbital resonances.

Saturn's many moons affect its rings through

orbital resonances.

A rock that contains 31 times as much argon-40 as potassium-40.

t= 6.25x10^9

What do the colors represent in the right image?

the intensity of the infrared light

By what factor has your weight increased? (Hint: Weight depends on the volume of your body.) Express your answer using one significant figure.

8

The nebular theory also predicts that the cloud will flatten into a disk as it shrinks in size. Which of the following best explains why the collapsing cloud should form a disk?

Colliding cloud particles exchange angular momentum and, on average, end up with the rotation pattern for the cloud as a whole.

Listed following are some distinguishing characteristics of comets, meteors, and asteroids. Match these to the appropriate category of objects.

Comets form a coma when near the Sun most are located either in Kuiper belt or Oort cloud visible in the sky as a fuzzy patch of light that rises and sets with the stars Meteors dust particles entering Earth's atmosphere at high speed visible in the sky as a bright streak of light for only a few seconds Asteriods compositions similar to that of the terrestrial planets typically orbit the Sun at approximately 3 AU

When you finish a problem, you should confirm that it makes sense and explain it if it does. Suppose you are grading a question in which students are asked to calculate the lifetime of the Sun. A student has submitted an answer of "10^−10 seconds." Which of the following would be the best response to give this student when you grade this question?

Incorrect. Your answer does not make sense, because the time is way too short.

What was the surprising result from the study published in Nature, as described in the article?

Investigation of recordings from sensors in the 1960s and 1970s suggested these events might happen more often than we think.

Why is Io more volcanically active than our moon?

Io has a different internal heat source.

Io experiences tidal heating primarily because __________.

Io's elliptical orbit causes the tidal force on Io to vary as it orbits Jupiter.

How does Berth's surface area compare to Earth's? Express your answer using one significant figure.

SBerth = 4 SEarth

Compare the surface area-to-volume ratios of the Earth and Venus. Express your answer using two significant figures.

SEarth/VEarth SVenus/VVenus= 0.95

Compare the surface area-to-volume ratios of the Moon and Mars. Express your answer using two significant figures.

SMoon/VMoon SMars/V Mars= 2.0

Assuming that other planetary systems form in the same way as our solar system formed, where would you expect to find terrestrial planets?

Terrestrial planets will likely be located nearer the planetary system's star than any jovian planets.

Based on the evidence that atmospheric carbon dioxide is a cause of planetary warming, what aspect of the graphs should most concern us?

The carbon dioxide concentration today is significantly higher than at any time in the past 800,000 years and is rapidly rising.

Based on your study of the Interactive Figure, which of the following is not one of the four major features of the solar system?

The solar system contains eight planets plus dwarf planets (including Ceres, Pluto, and Eris).

Which of the following statements best describes the general pattern of composition among the four jovian planets?

Uranus and Neptune contain relatively more rock and hydrogen compounds than Jupiter and Saturn.

Which planet is approximately halfway between Pluto's orbit and the Sun?

Uranus, the seventh planet from the Sun

How long have mammals been present on Earth?

about 225 million years

Which lists the major steps of solar system formation in the correct order?

collapse, condensation, accretion

The Rotation Curve for a Merry-Go-Round animation shows a rotating merry-go-round. Click several points on the merry-go-round, and watch the corresponding points appear on the graph below it. This graph is what we call a rotation curve, because it plots the speed at which any point rotates around the center (the orbital speed) against the distance of that point from the center. Based on the graph, you can conclude that doubling the distance of a point from the center of the merry-go-round would __________.

double its orbital speed

What fraction of extrasolar planets could in principle be detected by the transit method?

less than about 1%

The oxygen in Earth's atmosphere was released by

life

Saturn's rings look bright because __________.

light from the Sun reflects off the material in the rings

According to current understanding, the key requirement for life is

liquid water

Where is the most CO2 that has outgassed from Earth's volcanoes?

locked up in rocks

Now consider why the observed patterns of motion lead to the conclusion that the planets were not born in separate, random events. The reason for this conclusion is that, if the planets had been born in separate, random events, we would expect that __________.

planetary orbits would have many different orientations and directions, rather than all being in the same direction and in the same plane

Based on current data, planetary systems appear to be

present around at least 99% of all stars.

To determine a planet's average density, we can use

the transit and Doppler methods together.

Which travels fastest?

Light

Listed following are some of the distinguishing geological characteristics of the moons orbiting Jupiter. Match each characteristic to the appropriate moon.

Lo -source of ionized gas in the donut-shaped charged particle belt around Jupiter -hot, glowing lava visible in some photos -volcanoes currently erupting Europa -surface features provide evidence of a subsurface liquid ocean -ice covered surface with few impact craters -largest moon in the solar system -heavily cratered terrain adjacent to much younger terrain

Shown following are three terrestrial planets of our solar system. Rank the planets based on the amount of time the surface of the planet has had a moderate to high level of volcanic/tectonic activity, from longest to shortest.

Longest time -Earth -Mars -Mercury Shortest time