astronomy

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Place the following spectral types of stars in order from coolest to hottest.

"Oh Be A Fine Girl/Guy Kiss Me!" g2 f3 a8 a0 b9 b2

We normally write our address as a street number in a city or town, which is in a state or province, followed by a country. How would you state our cosmic address? Place its elements in sequence, starting with our planet and moving outward.

(smallest) earth, solar system, milky way galaxy, local group, supercluster, universe (largest)

Study the reactions in the figures and choose all the correct statements that follow from your observations.

- A single CNO cycle reaction will yield the same number of neutrinos as a single p-p chain reaction. - Both types of reaction create light.

Which of these actions would improve our chances of seeing this reaction and thus detecting the presence of a solar neutrino?

- Go to a place where there are a lot of solar neutrinos. - Build a detector made of a large amount of chlorine.

Calculations from the model of the nuclear reactions expected to occur in the Sun predicted that it would detect about 1 neutrino every day as it turned a chlorine atom into argon. In actuality, only 1 neutrino was detected about every 3 days. This was referred to as the solar neutrino problem. What might this problem imply?

- The detector may have been missing some neutrinos for some reason. - There were fewer neutrinos detected than expected, so something might be wrong with our models.

Which of the following values given for the Doppler shifts of astronomical bodies indicates that the object is approaching fastest (blueshifted)?

-0.06 nm

As a star forms, place the following in order of their occurrence.

-A cloud contracts under gravity. -A disk forms because angular momentum is conserved. -Nuclear reactions begin and a star is born. -Clumps form from static electricity. -Planetesimals form from collisions. -A wind blows from the central star.

Say you are trying to study the nuclear reactions in the Sun's core by observing photons coming off its surface. How will this random walk affect your results?

-Each photon would have been created a long time ago: it would be impossible to use them to study nuclear reactions as they are happening right now in the Sun's interior. -Each photon may be a different energy than it was when it was created in the nuclear reactions. -Each photon may be a different color than it was when it was created in the nuclear reactions.

Phases of the interstellar medium include

-hot, low density gas -cold, high density gas -cold, low density gas

The stars we see at night depend on

-our location on earth-the time of the observation-earths location in orbit

Here are five stars or star-like objects as we might observe them today. Eleven billion years from now, what will be the most probable state of each object? You may need to use the scroll bar to see all answer options from left to right.

.065 .9 1 .09 1.4

Rank the redshifts given here from the one for the galaxy closest to us to the one for the farthest.

.08 .36 2.14 3.05

What is the parallax of a star that is 28.00 light-years away?

.12

A typical temperature of intercloud gas is 7520.00 K. Using Wien's law, calculate the wavelength at which this gas would radiate most intensely.

.39

What is the parallax angle of a star that is 10,000 light-years away?

0.000326

What is the parallax angle of a star that is 7,500 light-years away?

0.000435

9.154 x 10-3 (Earth's diameter compared to the Sun's):

0.009154

9.154 x 10^-3 (Earth's diameter compared to the Sun's):

0.009154

A common radio wavelength observed coming from astronomical objects is 21 cm. What temperature is associated with this radiation?

0.014

For the hypothetical planet to make half an orbit around the Sun would take

0.0447 yrs

Compare this to the time Mercury takes to make half an orbit around the Sun, which is

0.120

Compare the gravity between these pairs, each consisting of an Earth-like planet and its star. You are given the mass of the planet in Earth masses, the mass of the star in Sun masses, and the distance in AUs.

1 2 2 4 2 3 1 1 1 2 1 1

Place the following numbers in order, from smallest to largest.

1. 7x10^12 2. 3 x 3. 700 4. 8x 5. 40 bil 6. 2x

Place the following regions of the Sun in order of increasing radius.

1. core 2. radiative 3. convective 4. photosphere 5. chromosphere 6. corona

Place in order the following steps in the fusion of hydrogen into helium.

1. two hydrogen 2. two gamma 3. one deuterium 4. two 3he

The period of Mars's orbit is 1.88 years. What is the distance of Mars's semimajor axis?

1.52

If Star A has twice the surface temperature of the Sun but has the same luminosity as the Sun, the diameter of Star A must be __________ the diameter of the Sun

1/4

Build upon this idea by comparing the shifts that would occur based on the baseline (B) used and the distance (d) to a star. For the first row of the table, we set B to 10 and d to 10 a shift of 1 (we compared it to itself). How does the next row's shift compare? We doubled the baseline but kept the distance the same, so the shift was 2 compared to the first example. Compare values for the rest of the table and then rank the shifts you compared from the smallest shift to the largest shift.

10 20 ? 10 10 1 15 10 ? 20 10 2

How does the luminosity of the more distant Cepheid compare to Delta Cephei's luminosity?

10.00

A nearby star, HH Andromedae , has a parallax of 0.317 arcseconds. How long does it take the light from this star to reach us?

10.28

The parallax angle for the star Sirius in the constellation of Canis Major is 0.379 arc seconds. The parallax angle for the star Rigel in the constellation of Orion is 0.00378 arc seconds. Approximately how much farther away from us is Rigel than Sirius?

100

What is the period between the first and second solar cycle on this graph?

11 years

Calculate the lifetime of a 6 MSun star.

113402303

The Earth rotates on its axis once every 24 hours. Due to this motion, roughly how many full hours would you expect to pass between two subsequent high tides at any given location on the Earth?

Rank the listed wavelengths from the one representing the highest photon energy to the one representing the lowest photon energy. The micron (10-6 m) wavelengths are represented by μm for micrometer.

121, 656, 6, 12

A star such as the Sun starts out as a protostar with a diameter a hundred times larger than its diameter during its main-sequence lifetime. Accordingly, the protostar's temperature is much less than its main-sequence temperature. Assume that while the Sun was a protostar it had a diameter 111.00 times that of the present-day Sun. How many times greater was the protostar's surface area?

12321.00

The Sun's temperature is 5780 K. Using the Stefan-Boltzmann law, calculate how many times greater the protostar's luminosity is compared to the present-day Sun using the diameter stated above and a surface temperature of 3330.00 K.

1357.41

Rank the following objects in order of their circular speeds from smallest to largest.

15 5 20 10

Sort the following blackbody curves of stars based on the region of the spectrum where most of the energy of the star is being radiated: ultraviolet wavelengths, visible wavelengths, or infrared wavelengths.

15 uv, 57 vis, 40 infrared

Closely examine the graphs of blackbody curves shown here and rank them from the one emitting the greatest amount of energy at 600 nm (indicated by the small orange circle) to the one emitting the least. Note the scale and the units for the y-axis.

15, 10, 6, 4

1.60934 x 103 (the number of meters in a mile):

1609.34

1.60934 x 10^3 (the number of meters in a mile):

1609.34

According to the graphs shown, by how much did the number of viruses increase in four time steps? (Remember, we start out with a single virus.)

16x

Halley's Comet has an orbital period of 76 years. What is the semimajor axis of its orbit?

17.9

We know that pulsars are rotating neutron stars. For a pulsar that rotates 27.00 times per second, at what radius in the pulsar's equatorial plane would a co-rotating satellite (rotating about the pulsar 27.00 times per second) have to be moving at the speed of light (300,000 km/s)?

1769.29

The approximate relationship between the luminosity and the period of Cepheid variables is 𝐿Cepheid(𝐿⊙)=335×𝑃(𝑑𝑎𝑦𝑠)LCepheid(L⊙)=335×P(days). What is the luminosity of Delta Cephei?

1809.00

You find a more distant Cepheid with a period of 54 days. What is its luminosity?

18090.00

The list shows a wide range of publishing years and values of the Hubble constant. Rank the items from the one implying the youngest universe to the one implying the oldest.

1929 1956 2019 2020 1970

1m2m 4m 1m1m 2m

Place the following in order from largest to smallest semimajor axis:

2 earth years 1 year .5 year 84 days

Using Wien's law: T = 2.9 x 106 nm•K÷ 1450 nm, what is the temperature of this star?

2,000 K

Our galaxy contains about 50,000 stars of average mass (0.5 solar masses) for every main-sequence star of 20 solar masses. But stars with 20 solar masses are about 104 times more luminous than the Sun, and 0.5-solar-mass stars are only 0.08 times as luminous as the Sun. How much more luminous is a single massive star than the total luminosity of the 50,000 less massive stars?

2.5

The average distance from Earth to the Moon is 384,000 km. How many days would it take, traveling at 800 km/h (the typical speed of a jet), to reach the Moon?

This image displays the Planck spectra, or blackbody curves, for four stars at different temperatures. The curves are adjusted so that they have the same brightness at 550 nm. Identify the temperature value for each blackbody curve. 20,000 K10,000 K5000 K2500 K

20 10 25 5

20 10 25 50

What would be the noontime altitude of the Sun at the winter solstice?

21.5

How many parsecs are in 7,500 light-years?

2300

If it takes sunlight eight minutes to reach Earth, how long does it take to reach Neptune , which is 30.1 times farther from the Sun than Earth is?

240.8

Two stars have the same luminosity, but Star A is 5.0 times farther away than Star B. How much fainter does Star A appear compared to Star B?

Our eyes are typically 6 cm apart. Suppose you are somewhat unique, and yours are 3.50 cm apart. You see an object jump from side to side by 0.75 degree as you blink back and forth between your eyes. How far away is the object?

267.40

Rank the following galaxies from the one that shows the smallest wavelength change in the Hα line at 656.3 nm to the largest change. (Note: The differences in how large the peak is depend on how much hydrogen emission is detected. Pay attention to the wavelength where the red dashed line above the x-axis is and compare it to the solid line with the label Hα.)

2903, 3368, 1357, 3147

Rank each object being pushed in order of increasing acceleration.

2m F0 2m F m F m 2F

Suppose an atom has three energy levels, specified in arbitrary units as 10, 7, and 5.In these units, which of the following energies might an emitted photon have?

3, 5, 2

A particular emission line (normally with rest wavelength 145.10145.10 nm) from a distant galaxy is observed at the same wavelength as the rest wavelength of the Hα line of hydrogen (656.28 nm). Calculate the redshift of this galaxy.

3.52

Delta Cephei is a bright Cepheid and has a pulsational period of 5.4 days and a parallax of 0.0033 arcseconds. How far away is Delta Cephei?

303.03

The more distant Cepheid variable appears 1/1,000 as bright as Delta Cephei. How far away is the more distant Cepheid variable?

30303.00

How many parsecs are in 10,000 light-years?

3070

Here is a colored sketch of the stars of the Big Dipper, with the colors representing their approximate surface temperatures. Label each star's distance from us.

31.9 26.3 37.7 24.4

If Stars 1, 2, and 3 all have the same apparent magnitude, rank the stars according to their size, from largest to smallest.

321

What is the minimum amount of time it would take a photon of light from Jupiter to reach Earth? See the visual reference for help.

34.9

What is the value of the smallest speed?

38.9

Your task is to convert 86,400 (the number of seconds in a day) and 0.0419 (the mass of a particular moon compared to the mass of its planet) to scientific notation.86,400 = 8.64 × 10N Enter the correct value for N.

The light-gathering power of a 4-meter telescope is __________ than that of a 2-meter telescope.

4 times larger

0.0419 = X × 10-2 Enter the correct value for X.(please use 4 decimal places in your answer)

4.1900

If it takes sunlight eight minutes to reach Earth, how long does it take to reach Jupiter , which is 5.2 times farther from the Sun than Earth is?

41.60

Assume you are at latitude 45.0 ° N. At what altitude would you see the north celestial pole?

Which point on the timeline corresponds to the Sun's current age?

The spectrum of a distant galaxy shows the Hα line of hydrogen (λrest = 0.656 microns) at a wavelength of 0.98400.9840 microns. This corresponds to a redshift of z = 0.500.50 and a recessional speed of 𝑣𝑟vr = 0.38 𝑐0.38 c . What is the distance to this galaxy in Mly?

5.18 x 10^3

A particular emission line (normally with rest wavelength 101.10101.10 nm) from a distant galaxy is observed at the same wavelength as the rest wavelength of the Hα line of hydrogen (656.28 nm). Calculate the redshift of this galaxy.

5.49

On average, how long does it take particles in the solar wind to reach Earth from the Sun if they are traveling at 300 km/s?

5.79

You should see how the nearer pencil shifts more than the farther pencil. This would give us two data points if we could measure each pencil's shift against a more distant object. In the next figure, the one you will be labeling, we've marked five different distances along the arm and given a series of possible shifts against a numbered grid. Your task here is to match the shift that would be observed with the distance from the nose, along the arm. (Only one side of the grid has been marked.)

56 48 33 18 3

56, 48, 33, 18, 3

A new star has been discovered that has a peak electromagnetic wavelength of 500.00 nm. What is the star's surface temperature?

5800

What is the temperature of the test star?

5800 K

What is the value of the largest speed?

59.0

A photon with a wavelength of 500 nm loses enough energy to change the photon's frequency to 5.00 × 1014 Hz.What is the new wavelength of the photon? What is the color of the new photon?

600 nm yellow

What would be the noontime altitude of the Sun at the time of the summer solstice?

68.5

Hubble's law relates the velocity and the distance of a galaxy. If Galaxy A is moving twice as fast as Galaxy B, then Galaxy A is twice as far away as Galaxy B; if Galaxy A is moving five times as fast as Galaxy B, then Galaxy A is five times farther away than Galaxy B. For this question, we give the distances of the galaxies and a value for the Hubble constant. Your task is to assign each galaxy the velocity we would measure from the redshifts of the lines in its spectrum.

740 3700 7400 37000

740, 3700, 7400, 37,000

The escape velocity from the Sun's surface today is 618 km/s. What will the escape velocity be when the Sun becomes an AGB star with a radius 50.00 times greater than its current radius, and a mass only 0.75 times greater than its current mass?

75.69

Using Wien's law, rank the following objects from shortest to longest wavelength of lambda peak. The temperature of each object is provided.

8 6 4 13 10

If an event were to take place on the Sun, how long would it take for the light it generates to reach us?

8 min

You have discovered the planet Zoltron. It is 4.0 times farther from the Sun than Earth (4.0 AU). How long does it take this planet to go once around the Sun?

8.0

How many times greater is the flux from a star that is 9.50 times hotter than our Sun?

8145.06

Newly forming stars are surrounded by gas and dust. Based on this observation--and your previous observations about the relative orbits, positions, and sizes of the planets--what is the most likely scenario for the formation of the Solar System?

A cloud of gas and dust collapsed into a flattened disk, within which the Sun and planets formed.

Given that gravity pulls downward at every point on the lens or mirror, select the telescope type that can get larger (more massive) and still retain its shape.

A cone

In order for an electron to jump up two energy levels in an atom at once, it requires

A precise amount of energy, A bluer photon than to jump up one energy level, More energy than to jump up one energy level

What does all of this imply about how stars form from molecular clouds?

A single molecular cloud fragments as it collapses, forming many stars at once.

Based on this graph, which statement best describes how the luminosity of a main-sequence star compares to its mass?

A star with ten times the mass of the Sun will have a luminosity that is more than ten times the luminosity of the Sun.

Label the four general luminosity classes of stars on the H-R diagram. White dwarfsMain sequenceGiantsSupergiants

ABDC

Suppose Jupiter were not a planet, but instead were a G5 main-sequence star with a mass of 0.8 MSun. How could this affect the Sun as the G5 star came to the end of its life?

Which of these hypothetical situations would allow the temperature of the Sun's core to rise enough for carbon fusion to be possible?

Add mass to the Sun.

Which of the following best describes your observations?

All of the stars move in a counterclockwise path around Polaris. The stars closest to Polaris move in smaller circles.

With this goal in mind, watch the Introduction of the AstroTour Animation on Solar System Formation. Pay attention to the animation of the planets in the Solar System and select all of the following choices that describe the patterns that you've observed. As you do so, think about the implications of how the Solar System may have formed.

All planets orbit the Sun in the same direction. The orbits of the outer planets (those most distant from the Sun) are spaced farther apart from one another than the orbits of the inner planets. All planets orbit the sun in a rougly flat plane. The closest planets to the Sun are much smaller than the planets that are farther away.

All planets orbit the sun in a rougly flat plane. All planets orbit the Sun in the same direction. The closest planets to the Sun are much smaller than the planets that are farther away. The orbits of the outer planets (those most distant from the Sun) are spaced farther apart from one another than the orbits of the inner planets.

According to the scientific method, choose all of the following statements that are correct.

All theories have enough supporting evidence behind them that we can move forward under the assumption that they are correct unless some future test proves that this is not the case. A theory has a higher probability of accurately modeling a natural phenomenon than a hypothesis does.

Why type of spectra would you expect to get from the stars and from the gas?

An absorption spectrum from the stars and an emission spectrum from the gas

Which of the following has contributed most to our understanding of the process of star formation?

Astronomers have observed many different stars at each step of the formation process.

Label each marked position of Mars with the phrase that most accurately describes its apparent motion in our sky against the background stars.

B pro fast A ret C pro slow

Which of the following shapes best represents Earth's orbit?

B. circle

Label these important reference points in your sky.

BACD

Place each star, identified by spectral type and luminosity class, in its proper place on the H-R diagram.

BAEDC

All Type Ia supernovae

Label these important reference points. Their location in your sky depends on your location on Earth.

BCAD

Label each blackbody curve with the estimate of its peak wavelength, defined as where the curve of the line reaches its highest relative intensity.

BDCA

Refer to the spectrum of hydrogen in the figure above. Why is the excited hydrogen gas in the image of Gum 41 glowing red?

Because of its atomic structure, hydrogen gas has a transition between excited states that produces red light.

The following image represents a section of the H-R diagram. Use the image as a guide to rank the stars according to their relative temperatures, from coolest to hottest.

Betelgeuse, aldebaran, the sun, polaris, vega, rigel

Label the stars by their relative surface temperature, based on the habitable zones shown in green. High temperatureMidrange temperatureLow temperature

CAB

The diagram shows the configuration of the Sun, Earth, and Moon during a solar eclipse, and the regions on Earth from which the solar eclipse is visible. Identify how much of the eclipse can be seen at each location on Earth by dragging each label to the corresponding target.

CABD

In a high-mass star, hydrogen fusion occurs via the

CNO cycle.

If your hypothesis has passed nine tests, but fails the tenth one, what do you do?

Change the hypothesis or create a new one, then come up with new predictions and conduct more tests.

With this in mind, choose the label to the lightest element in the graph that will not burn under ordinary conditions in a star.

Rank the parts of the Earth on the figure in order of decreasing gravitational force felt from the Moon.

D B ECA

The diagram shows the zodiacal constellations viewable from Earth at different seasons. Label the month that the Sun appears in each marked constellation.

D may A april C march B october

Match the appropriate descriptions of luminosity, temperature, and size of stars to the correct portion of the H-R diagram.

DB CA

Match the eccentricity values with the properly shaped ellipse.

DBFC

Identify each region of the electromagnetic spectrum by correctly placing the names listed.

DECAFB

How does the spectrum of a distant star reveal the star's chemical composition?

Dark lines, also called absorption lines, within the spectra are "fingerprints" for the different atoms and molecules within a star's atmosphere.

If the Sun instantaneously stopped giving off light, what would happen on Earth?

Earth would get dark 8 minutes later.

What causes the angle of the Sun to change over the year?

Earth's North Pole always points in the same direction in space. Sometimes this is toward the Sun, and sometimes it's away from the Sun.

A lunar eclipse occurs when the ________ shadow falls on the ________.

Earth's; Moon

Match the following properties of telescopes with their corresponding definitions.

FCABDE

The mass of hydrogen is 1.6726 x 10-27 kg, and the mass of helium is 6.6465 x 10-27 kg. Given this, which of the following nuclear reactions would result in a decrease of total mass, and thus a release of energy, while keeping the same number of particles involved?

Four hydrogen nuclei combine into one helium nucleus.

Study the sizes of the gas giants shown in the image above (the distance from the Sun increases from left to right), and choose the best explanation that accounts for their differences in size.

Gas giants decrease in size with increased distance from the Sun because the Solar Nebula was less dense farther out.

Think about how you would expect the temperatures in the star to vary between each of the layers shown, and use this to sort the following elements in order of increasing temperature at which they burn in a nuclear fusion reaction.

H He C Ne O S

View the AstroTour animation on Kepler's Laws and then choose the statements below that are correct.

Halley's Comet has a highly eccentric orbit. Elliptical orbits cause a planet to sometimes be closer to and sometimes farther away from the Sun.

As material from the outer envelope of the larger star builds up on the surface of the white dwarf, its temperature and density increase continuously. Under this scenario, what is the first event that will eventually happen?

Hydrogen on the surface of the white dwarf will undergo nuclear fusion.

Each image shows a part of a star, with the relative strength of its self-gravity and pressure shown by the length of the blue arrow. Match each star with the description of the state it is in.

Hydrostatic equilibrium - 3 red arrows with shortest blue Collapsing - 3 red with longer blue Expanding - 2 red

Study this picture of a meteorite that has been sliced open to show its interior, and use your observations to determine the most likely formation scenario for a planet.

Individual particles in the nebula stick together to form larger pieces which later collide with and stick to other pieces to gradually form larger objects, which eventually grow to the size of a planet.

The resulting nucleus is not the same type of element as either of the two that entered the collision. Why not?

It gained a proton.

What is a neutrino?

It is an almost massless, neutral particle that is produced in nuclear processes.

While on the main sequence, a star is stable because there is a balance between its self-gravity trying to make the star collapse in on itself and the outward pressure of the gas heated by nuclear fusion trying to make it expand. When the core of a star runs out of fuel and nuclear fusion stops, what will happen to the star?

It will collapse.

As an observer on the right-hand side of the cloud (viewing light from an object after it has passed through the dust), how will your view of the color of the object be affected by the dust?

It will look redder than it would if the cloud were not there.

A white dwarf no longer has any ongoing energy production from nuclear fusion, so it will continuously cool off with time. Taking into consideration all the forces acting on each piece of the white dwarf, what will happen to it as it cools?

It will stay constant in size.

Study the following figure. If it were possible to watch a high-mass star move to the right along one of the post-main-sequence lines, what would happen to the star's size?

It would become much larger.

If the integration time is long enough to collect the light from this entire animation, what effect would seeing have on the image of the object?

It would blur the light from the object, effectively increasing the angular resolution of the telescope.

Both Kepler's laws and Newton's laws tell us something about the motion of the planets, but there are fundamental differences between them. What are the differences? Select all of the true statements.

Kepler defined Kepler reported Kepler's approach

Imagine decreasing the size of the lens in the figure above. Which choice below best describes what would happen?

Less total light from the source will hit the lens, making it appear fainter on the detector.

Arrange these stars in order of their luminosity. Their radii and temperatures are given in relation to the Sun, as multiples of the Sun's radius and temperature. For example, "R2, T4" indicates that the star's radius is two times the Sun's radius, and its temperature is four times the Sun's.

Lowest 1. R2, T2 2. R3, T2 3. R4, T2 4. R2, T3 5. R2, T4 6. R4, T4 Highest

The resolution of radio telescopes suffers greatly from the large wavelengths of the light they are observing. What can be done to a radio telescope to improve its angular resolution?

Make its dish bigger.

In 1500s, Copernicus reintroduced the heliocentric model that the ancient Greeks had rejected, and it began to gain favor among some scientists. He suggested that the planets all orbit around the Sun in perfect circles, as shown in the figure to the right. This offers a much more elegant explanation of retrograde planetary motion than the geocentric model.

Make predictions from Copernicus's model, and verify them with observations.

Which of the following would be the best way to find experimental evidence of the different types of materials that condensed as a function of distance from the Sun during the period of accretion in the Solar Nebula?

Measure the composition of meteorites that originated from different locations within the Solar System.

How does mass determine the main-sequence lifetime of a star?

More massive stars burn fuel faster than low-mass stars and thus have shorter lives.

Examine the table here, and use what you learn from it to choose the correct statement.

More massive stars emit more energy and run out of hydrogen fuel in their cores faster.

Given that more massive stars emit more energy, choose the most logical statement following the table.

More massive stars have shorter main-sequence lifetimes because they burn through their fuel at a faster rate.

How do neutrinos help us understand what is going on in the core of the Sun?

Neutrinos from the interior of the Sun easily escape.

Would the anecdotal verbal account from this witness be valid scientific evidence of the event?

No, because follow-up tests conducted by others cannot verify it.

Consider the hypothesis that, although the land appears to be flat, there is enough of a slope that gravity is the only force causing the rocks to move. Based on the scientists' findings and the tracks shown, is this hypothesis verified?

No. The rocks' behavior is too eratic for gravity to be the only cause. Some other force that changes randomly with time must be involved.

Rank the lifetimes of these main-sequence stars from shortest to longest.

O4 B3 A6 F0 F7 G2

Study the figure, which shows the line of sight between Earth and two stars. Choose the answer that most closely matches what we would observe in our sky, according to this figure, if the Earth orbits around the Sun.

Over the course of a year, stars should appear to move back and forth, with stars closer to us moving a larger distance.

For Earth, P2/A3 = 1.0 (in appropriate units). Suppose a new dwarf planet is discovered that is 14 times as far from the Sun as Earth is. For this planet

P2/A3 = 1.0.

Why do photons take so much longer than neutrinos to emerge from the Sun?

Photons interact strongly with matter, while neutrinos do not.

Besides adding adaptive optics to a telescope, what else can be done to reduce the effects of seeing?

Put the telescope at a higher altitude (the height above sea level).

The following images show the entire sky taken in different wavelengths (X = X-ray, V = visible, and R = radio). Choose the image with the type of gas that is most likely to collapse under its own self-gravity.

Using your knowledge of blackbody radiation from previous chapters, rank the following three pieces of interstellar medium in order of increasing temperature. The wavelength each image was taken in is displayed in bold, where G = gamma ray, X = X-ray, U = ultraviolet, V = visible, I = infrared, and R = radio.

RVX

Rank the types of radiation in order of their energy, from least to greatest.

Radio waves infrared red visible light blue visible light X-rays gamma rays

Astronomers have determined that the gas giants are made mostly of hydrogen and helium. Given what you have learned about planetesimal formation through accretion, and the types of materials that condensed at certain distances from the Sun, which of the following is the most likely way that the gas giants formed?

Rock, metal, and ices made of materials such as water, ammonia, and methane, condensed into a solid and grew large enough to gravitationally attract hydrogen and helium gas from the Solar Nebula.

Two of the images you worked with in this activity in your workbook were taken by space-based observatories: Chandra (X-ray) and Spitzer Space Telescope (infrared). Which of the following correctly explains the reason we needed space telescopes for these two images?

Space-based telescopes observe portions of the spectrum blocked by Earth's atmosphere.

From the vantage point of Earth in the diagram shown, how will the parallax of Star A compare to that of Star B?

Star A has twice the parallax of Star B.

Stars A and B appear equally bright, but star A is twice as far away from us as star B. Which of the following is true?

Star A is 4 times as luminous as star B.

Identify the statement that best describes how the latitude of sunspots varies over a sunspot cycle, which is defined to begin at solar minimum.

Sunspots are at higher latitudes at the beginning of a cycle, and lower latitudes at the end of the cycle.

"I was given the answer to this question in a prophetic dream."

Tests must be repeatable by anyone.

Given the sense of rotation in the figure, and the location of the Earth's bulge with respect to the Moon, what effect would you expect to come from this reaction force?

The Earth's day will become longer with time.

Newton's third law says that for every force there is an equal reaction force in the opposite direction. What does this imply about the force of gravity associated with a person standing on the Earth?

The Earth's gravity pulls downward on the person, and the person's gravity pulls upward on the Earth.

At this instant, where is the first quarter Moon in the person's sky?

The Moon is high in the south.

Suppose an abnormally large amount of hydrogen suddenly burned in the core of the Sun. Which of the following would be observed first?

The Sun would emit more neutrinos.

Watch the AstroTour on Velocity, Acceleration, and Inertia, and then choose the answer that best describes what Galileo's experiment implies.

The acceleration of all objects dropped from the tower is the same.

How do the temperatures of the brightest stars in the sky compare to the temperature of the nearest stars?

The brightest stars are hotter than the nearest stars.

How do the luminosities of the brightest stars in the Sky compare to the luminosities of the nearest stars?

The brightest stars are more luminous than the nearest stars.

Based on the law of conservation of angular momentum, what would happen to a collapsing cloud of gas and dust--isolated in space with no external forces--as its size decreases?

The cloud will spin faster.

F is the force that is causing the object to accelerate. In the case of dropping objects from a height, the force that causes them to accelerate toward the Earth is gravity. If the acceleration of objects dropped from a height does not depend on the object's mass (as shown by Galileo's experiment), what does this imply about the force of gravity?

The force of gravity increases with increased mass.

Newton's second law says that the acceleration (a) of an object depends on its mass (m) by the equation: $$a=Fm F is the force that is causing the object to accelerate. In the case of dropping objects from a height, the force that causes them to accelerate toward the Earth is gravity. If the acceleration of objects dropped from a height does not depend on the object's mass (as shown by Galileo's experiment), what does this imply about the force of gravity?

The force of gravity increases with increased mass.

What can you conclude from this, assuming that the geocentric model holds that the Sun, Moon, and planets like Mars all orbit around Earth in simple circles?

The geocentric model is wrong because it falsely predicts that Mars should always move in the same direction with respect to the stars.

How does the heliocentric model explain the retrograde motion of Mars?

The heliocentric model explains retrograde motion because Mars only appears to move backward as Earth passes it in its orbit around the Sun.

Which of the following statements about massive stars having the shortest lifetimes is not true?

The higher a star's mass, the greater the percent of heavier elements from which it formed, and heavier elements burn hotter and faster.

Based on this and the descriptions in the figure, why does it then expand in size during the red giant phase?

The hydrogen shell burning is producing more total energy than the core hydrogen burning did.

If you had a telescope with the same-sized lens (and same focal length) as the human eye, what would be the benefit of taking an exposure of a steady light source with an integration time of 10 seconds?

The light source would appear brighter in the image.

An experienced astronomer can take one look at the H-R diagram of a star cluster and immediately estimate its age.Select the statement that explains how this is possible.

The most massive stars remaining on the main sequence indicate the cluster's age.

Did the neutrino enter the reaction, or was the neutrino produced in the reaction?

The neutrino was produced in the reaction.

Watch the AstroTour on The Solar Core. Then choose the condition that would make it more likely for two nuclei to fuse together.

The nuclei are moving fast with respect to one another.

What happens to the period when you make the semimajor axis larger?

The period increases.

Which of the following most closely explains what we would see from Earth according to the geocentric model that includes epicycles?

The planets would usually move west to east through the stars, but they appear to reverse direction when they are on the part of the epicycle that has motion opposite to that of the larger circle.

If there were two telescopes with the same diameter, but one is a visible light telescope and the other a radio telescope, how would the resolution of the images from each telescope compare? The wavelength of visible light is several hundred nanometers (1 nanometer = 10-9 meters), and radio can be several centimeters (1 cm = 10-2 meters) or several meters.

The radio telescope would have much worse angular resolution.

Decrease the wavelength, using the arrow key. What happens to the rate of the frequency counter?

The rate of the frequency counter increases.

Describe how the slope (rate of change of number of viruses per time step) varies across this plot.

The slope increases with increased time step.

The Hyashi track is a nearly vertical evolutionary track on the H-R diagram. What does the vertical nature of this track tell you about a protostar as it moves along it?

The star remains the same color.

Which of the following describe how a more evolved high-mass star will differ from when it was on the main sequence?

The star will become redder in color. The star will become larger in diameter. The star will change spectral type.

If dust between a star and Earth absorbs and/or scatters away some of the star's light, and this is not accounted for in calculations of the distance to the star, how would it affect the results?

The star would appear to be farther away than it really is.

Celestial motions over time periods longer than a day are less obvious. Say you went out at exactly the same time each night and looked at the sky, noting the position of a specific set of stars at that time with respect to reference objects on Earth, such as trees and buildings. The following figure shows how the stars would change position. Based on this figure, what is the most correct conclusion?

The stars appear to move westward from one night to the next.

However, they did not measure stellar parallax—the stars did not appear to move back and forth at all over the course of a year. What is the most likely reason for this apparent lack of motion?

The stars must be so distant that their parallaxes are too small for the ancient Greeks to have been able to measure with their technology.

How will the gravitational force on a piece of the surface of the star (m1) by the mass of the rest of the star (m2) (effectively located at a point at the center of the star) compare between the AGB and main-sequence phases of a particular star, assuming its mass stays the same?

The surface will feel a weaker gravitational force during the AGB phase because it is farther from the center of the star.

Space telescopes that exist in orbit above most of Earth's atmosphere are expensive, so they must therefore be supported with a very compelling motivation. If you were trying to justify funding for a space telescope in orbit around the Earth, which of the following would be the best argument to use?

The telescope could observe wavelengths of light that are not visible from the ground.

Suppose that a space telescope has been designed that can produce sharp images in visible light. Then a proposal is made to redesign the telescope so that it has a considerably larger focal length but a considerably smaller aperture. Which of the following is an accurate statement of the advantages and/or disadvantages of the new design?

The telescope will be less able to detect dim objects, and it will be less able to resolvefine detail, especially at longer wavelengths.

What changes about the image of the test star next to the Sun?

The test star becomes larger, brighter, and redder.

Consider all the evidence about variations in the Sun's influence on the Earth throughout the year. Based on this evidence, what causes the seasons?

The tilt of the Earth's rotation axis to its orbit around the Sun causes parts of the Earth to experience more direct illumination from the Sun and longer days during the summer than the winter.

Which of the following hypotheses about the bizarre motion of sailing rocks relies on the fewest assumptions?

The wind moves the rocks.

If the Moon were in the same orbital plane as Earth's orbit around the Sun, which of the following would happen? (Choose all that apply.)

There would be a lunar eclipse every lunar orbit (roughly every month). There would be a solar eclipse every lunar orbit (roughly every month). The phases of the Moon would remain unchanged.

Astronauts in a space shuttle can float while orbiting Earth. Why are these astronauts weightless?

They are falling around Earth at the same rate as the shuttle.

Why does the angle of the Sun's rays matter in regard to Earth's seasons?

They are more spread out if they strike at an angle.

Why don't we see cars as bluer when they approach and redder when they recede?

They are too slow.

What likely happened to the other stars in the cluster the Sun was born in?

They moved away from the Sun over the past 4.5 billion years.

How did the ancients know the planets were different from the stars?

They saw that the planets move with respect to the stars over the course of many nights.

What effects will the efficient fusion and high core temperatures have on high-mass stars?

They will burn through their hydrogen more quickly, owing to both the efficiency of the CNO cycle and the higher core temperature.

As neutrinos travel through the Sun's dense interior, how will their path change due to the presence of the gravitational, electromagnetic, and nuclear strong forces around them?

They will not change at all.

Watch the AstroTour on Kepler's Laws and choose the statement below that directly follows from Kepler's second law of planetary motion.

Venus is traveling faster when it is at perihelion (the closest distance to the Sun) than when it is at aphelion (the farthest distance from the Sun).

How are the wavelength and frequency related to each other?

Wavelength and frequency are inversely related.

Watch the first section, and click through, using the "Play" button until you reach Section 2 of 3.Here we will explore the following questions: How many properties does a wave have? Are any of these related to each other?Work your way through to the experimental section, where you can adjust the properties of the wave. Watch the simulation for a moment to see how fast the frequency counter increases.How are the wavelength and frequency related to each other?

Wavelength and frequency are inversely related.

The number of galaxies counted in the Hubble Deep Field North image, taken of a very small angular area of the celestial sphere, implies that there are about 40 billion galaxies in the observable universe. Why wouldn't this count be the number of galaxies in the entire universe? Why would the observable universe differ from the entire universe?

We are able to observe only that part of the universe where light has had time to reach us.

We use the unique patterns every day to help us solve crimes, identify genetic features, keep track of inventory, and more. Astronomers use the unique patterns that atoms and molecules have in spectra to find the composition of stars. Why is it important that the patterns be unique?

We can figure out the compositions of distant stars just by looking at their spectra. The unique patterns serve as unmistakable "fingerprints" of the atoms and molecules present.

What is the most likely reason for the difference seen here in the Milky Way?

Based on the white dwarf's position in the H-R diagram, which of the following statements is true?

White dwarfs are fainter than stars in other stages at the same temperature because they are smaller.

Count the number of squares in the yellow area and in the red area. You will need to decide what to do with fractional squares.Are the areas the same?

Yes

Should they be?

Yes

Imagine a planet moving in a perfectly circular orbit around the Sun. Is this planet experiencing acceleration?

Yes. It is changing its direction of motion all the time.

Can this new information solve the neutrino problem and confirm that our models of nuclear reactions in the Sun are correct?

Yes. The existence of three different types of neutrinos would account for the missing neutrinos observed over the number that were predicted.

Imagine you are walking along a forest path. Which of the following is not an action-reaction pair in this situation?

You push down on Earth; Earth pushes you forward.

Place the following steps of the evolution of a low-mass star in order.

a clump hydrogen the star moves red giant the star moves horizontal the star moves asymptotic the white dwarf cools

Label the plot with the matching orbital positions of the stars at each marked time.

a down long up d left right c long down up b small left right

Label these important places on the celestial sphere.

a north d ecliptic c celestial b south

When an electron moves from a higher energy level to a lower energy level in an atom,

a photon is emitted.

The resolution of the human eye is 1 arcminute, or 1/60th of a degree. If the light of two street lamps in the distance is separated by 0.5 arcminute, what will you see with your eyes?

a single light, with the combined brightness of each street lamp

Choose all that apply. CCD cameras are better astronomical detectors than the human eye because

a. their quantum efficiency is higher. b. the integration time can be longer. c. they can observe at wavelengths beyond the visible.

The average distance of Mars from the Sun is 1.4 AU. How bright is the Sun on Mars compared with its brightness on Earth?

about 2 times fainter

Iron fusion cannot support a star because iron

absorbs energy when it fuses

Imagine that the binary stars in each of the pictures are observed from a telescope located somewhere below the image. Spectra of both stars are taken, and used to find radial velocities for each, which are graphed as a function of time in the plot (Star 1: pink, outer-most orbit; Star 2: blue, inner-most orbit).Label the plot with the matching orbital positions of the stars at each marked time.

adcb

At which of these times would the person shown on Earth be able to observe this waxing crescent Moon?

after sunset

A net force must be acting when an object

all

A net force must be acting when an object (select all that apply):

all

The apparent larger shift of the closer poles to the more distant ones was due to

all 3

When you see a pattern in nature, it is usually evidence of

an underlying physical law.

Drag the labels to each of the spectral types in order of decreasing strength of these hydrogen lines (strongest absorption first, weakest last). Strongest absorptionWeakest absorption

ao bo fo go ko

Constellations are groups of stars that

are close to one another in Earth's sky.

How would you describe the shape of Mercury's orbit?

as an ellipse

Very young star clusters have main-sequence turnoffs

at the top left of the main sequence.

The "square" in the inverse square law for intensity of light means that

at three times the distance, the intensity is 1/9 as great.

An extremely hot object emits most of its light

at very high energies

The angular resolution of a ground-based telescope is usually determined by

atmospheric seeing.

Sort each of the following particles into the appropriate bin according to the electromagnetic force it would feel in the presence of a hydrogen nucleus. The relative charge of each particle is displayed on it.

attracted -1 repelled +1 no 0

The following image is a schematic of the triple-alpha fusion process. Place each label in the correct position on the image.

badc

The following image shows the lifetime of a low-mass star on the H-R diagram. Place each label in the correct position on the image.

bceda

Rank the distances to the stars listed in the table based on their parallax shifts given in arcseconds.

bella bet alnitak rigel alnilam

Place these images that depict different states of evolution for a planetary system in chronological order.

biggest blob, smaller blob, one with purple, one with solar system

Rank the phases of the Moon in the order they appear in one lunar cycle as seen from the Northern Hemisphere, starting with a new Moon. You may need to click on the arrow to scroll through the full range of possibilities.

black right cres

When you look at the sky on a dark night and see stars of different colors, which are the hottest?

blue

Rank each of the following colors by how much each refracts, from most (at top) to least (at bottom).

blue green red

What happens to the appearance of an object as it gets hotter?

bluer and brighter

Light acts like

both a wave and a particle

The tilt of Earth's axis causes the seasons because

both b and c are correct.

The following image shows a cross section of a horizontal branch star. Place each label in the correct position on the image.

burning helium burning hydrogen nonburning hydrogen

Label the stars by their relative surface temperature, based on the habitable zones shown in green.

c low a high b midrange

In the elliptical orbit shown, the given areas were made in the same amount of time. Match the correct description of the change in speed the planet would experience to the proper segment.

c speeding up & slowin down a slowing down all the time d slowing then speeding

For this question, your task is to identify what is being displayed in each coconut-kiwi pair (or just two coconuts).

cab

The growth of a red giant can be compared to the growth of a snowball going downhill. Every change in the conditions inside the star leads to even more rapid change and growth. Order these steps in the snowballing growth of a red giant.

cadbe

Based on these spectra, identify the elements present in each blended spectrum.

cba

The following figure displays the evolutionary track of a 1-MSun star. Place each description of the evolutionary stage in its correct location. You may need to use the scrollbar to view all answer options.

cedba

No matter where you are on Earth, stars appear to rotate about a point called the

celestial pole.

How does the total change (final minus initial) in the properties of a protostar from the beginning of this track to its end compare between a star with five times the mass of our Sun, and a star with the mass of our Sun? Careful: this is a logarithmic plot.

changes its temp, luminosity, radius

Which of the following shapes best represents Earth's orbit?

circle

An inferior planet is one that is

closer to the Sun than Earth is.

When hydrogen is fused into helium, energy is released from

conversion of mass to energy.

Locate a periodic table of the elements such as the one in your book, and use it to determine which of the following elements are produced only in supernova explosions.

copper, silver, gold

Label each region of the Sun with the most important process that is happening there. Energy radiates outward at the speed of light.Nuclear fusion reactions create energy.Moving matter physically transports energy outward.Energy is absorbed, emitted, and deflected by matter in unpredictable directions.

core nuclear radiative energy is absorbed connective moving

Drag the labels to each of the spectral types in order of decreasing strength of these hydrogen lines (strongest absorption first, weakest last).

d a e b c

Four transitions are shown in the image. Order the transitions in the order of increasing energy.

dcba

As wavelength increases, the energy of a photon __________ and its frequency __________.

decreases; decreases

Cameras that use adaptive optics provide higher spatial-resolution images primarily because

deformable mirrors are used to correct the blurring due to Earth's atmosphere.

A molecular cloud fragments as it collapses because

density variations from place to place grow larger as the cloud collapses.

Based on the figure in the Introduction, and the fact that an object with an increasing moment of inertia will spin more slowly to conserve angular momentum, choose the figure that best depicts how a cloud of gas will collapse to form a star system.

disk

A light-year is a measure of

distance

Interstellar dust is effective at blocking visible light because

dust grains are so small.

This H-R diagram shows five possible protostar evolutionary tracks, each one ending at the main sequence. Match each main-sequence lifetime with the star that would result from each evolutionary track.

e a c b d

How many neutrons are in the nucleus represented by the bottom red ball?

e and f

If the Sun were a member of globular cluster, that cluster's H-R diagram would fall between

e and f

This H-R diagram shows five possible protostar evolutionary tracks, each one ending at the main sequence. Match the given main-sequence lifetimes with the star that would result from each evolutionary track.

eacbd

Identify each of the following six planets and order them by distance from the Sun. You may need to scroll right to view all of the images.

earth peach stripes saturn blue blue w white

How would you describe the shape of Mercury's orbit?

ellipse

Sort each of the graphs shown into the bin describing the type of spectrum plotted.

emission - shoots up middle planck - black absorption - high to low

A white dwarf will become a supernova if

enough mass accretes from a companion to give the white dwarf a total mass of 1.38 MSun.

Sort the following statements between being an example of the parallax effect or being just an illusion.

example our eyes nearby trees moon not example web design parallel train

When Earth catches up to a slower-moving outer planet and passes it in its orbit, in the same way that a faster runner overtakes a slower runner in an outside lane, the outer planet

exhibits retrograde motion.

Elements heavier than iron originate:

explosions of high-mass stars

Match each graph to the appropriate evolutionary stage of the Sun.

flat starts med starts high

Determining what causes the seasons is not as straightforward as determining what causes day and night. We can begin by suggesting hypotheses and then testing them for their validity. Let's start with the hypothesis that the seasons are caused by a variable distance between the Earth and the Sun. Sort the observations or physical laws below according to whether they argue for or against this hypothesis.

for hypothesis: Closer light source has stronger intensity. and Earth's orbit is elliptical. against hypothesis: Earth's closest approach to Sun is in January. and S and N hemispheres have opposite seasons.

The image provided shows a light source moving relative to three different observers: Fred, Velma, and Daphne. If the light source is emitting green light and moving with sufficient speed, identify which colors each person could possibly see.

fred - red velma - blue daphne - green

Imagine two objects moving away from you. Object A is faster than object B. You will observe that the light

from both objects is redshifted.

Based on what you have learned about light from previous chapters, how would we determine what this gas in the interstellar medium is made of?

from the wavelength of absorption lines in the spectra of stars whose light passes through the gas

The layers in a high-mass star occur in order of

fusion temperature

The scientific method is a process by which scientists

gain confidence in theories by failing to prove them wrong.

Study the AstroTour about The Solar Core. Then select all the particles/elements that are created by the reaction.

gamma ray neutrino helium positron

The following images are famous examples of different astronomical bodies. Label each image accordingly.

glob open supernova

Stars begin burning helium to carbon when the temperature rises in the core. This temperature increase is caused by

gravitational collapse.

Why do the outer layers fall onto the core?

gravity

A pulsar occurs when a neutron star

has a magnetic axis that is not aligned with the rotation axis.

The interior of an evolved high-mass star has layers like an onion because

heavier atoms fuse closer to the center, where the temperature and pressure are higher.

Identify the element whose emission spectrum is shown in the graph by comparing it to the known spectra of five different elements.

helium

At this instant, where is the first quarter Moon in the person's sky?

high in south

Eta Carinae is an extreme example of a

high temp & massive

Place in order the stages of nuclear burning that evolving high-mass stars experience.

hydrogen helium carbon neon oxygen silicon

Occam's razor states that

if two hypotheses fit the facts equally well, choose the simpler one.

Based on these graphs of the Sun's pressure, density, and temperature in its interior, where are the nuclear reactions occurring?

in a central region 20% the size of the entire Sun

If the distance between Earth and the Sun were cut in half, the gravitational force between these two objects would

increase by a factor of 4.

If we wanted to increase the Hubble Space Telescope's altitude above Earth and keep it in a stable orbit, we also would need to

increase its orbital speed.

This next image is of the same molecular cloud, but taken with a filter selecting a different set of wavelengths. Label the image with the part of the electromagnetic spectrum it was likely imaged in.

infrared

Dust in the interstellar medium can be observed in

infrared radiation

Building effective detectors for particles or waves that scientists would like to study is a real challenge. Some are easily detected, while others are not. Rank the following items in order of increasing difficulty of detection.

infrared, neut, gravity

Sort the particles into the categories describing whether they are input particles that get used up in the reaction, new output particles persisting after the reaction, or intermediate particles that exist only temporarily during the reaction.

input: Hydrogen, electron output: Neutrino, Gamma Ray, Helium-4 intermediate:Deuterium, Helium-3, Positron

Assuming that each of the following objects is a typical example of its class, rank them by increasing density.

intercloud interstellar molecular protostar star

The following graph depicts nucleosynthesis within stars. It plots the average binding energy per nucleon versus the number of nucleons in a nucleus. The dots are the locations of various elements within the graph.

iron cannot

The following images show different stages of a Type II supernova. Place them in chronological order. For reference, the black arrows represent neutrinos streaming from the core, and the colorful arrows represent the physical motion of material within the star.

iron core neutrinos streaming pointing out shock wave white

The celestial equator

is directly above Earth's equator

Polaris, the North Star, is unique because it

is the only star in the sky that doesn't move throughout the night.

Warm neutral hydrogen can be detected because

it emits light when electrons drop through energy levels.

Copernicus's model of the Solar System was superior to Ptolemy's because

it had a mathematical basis that could be used to predict the positions of planets.

If the energy leaving the planet is restricted, what happens to the temperature of the planet?

it increases

When the Sun runs out of hydrogen in its core, it will become larger and more luminous because

it starts fusing hydrogen in a shell around a helium core.

A pulsar "pulses" because

its magnetic axis crosses our line of sight.

Ordinarily, the hotter an object is, the more luminous it is. In this case, the temperature has gone down, but the luminosity has gone up. How can this be?

larger

Based on your observations of this diagram, choose all the statements that correctly describe what is happening to the star during this time.

larger and redder

Four transitions are shown in the image. Identify the transitions in order of increasing wavelength of the photon that each transition would emit.

largest, second largest, second smallest, smallest

When a star like the Sun moves up the red giant branch in the H-R diagram, it begins to burn hydrogen to helium in a shell surrounding a degenerate helium core. This cycle speeds up over time. In the following figure, label the descriptions of the missing steps in the cycle.

left c an increase mid a a higher right b a greater

In the binary system shown here, a small blue star orbits a larger red star, moving from left to right in front of the red star. Match the orientation of the stars to the appearance of the light curve of the system.

left front right none

Place the following two types of radiation in the appropriate place on the electromagnetic spectrum.

left gamma right radio

Place each star at its correct position on the H-R diagram.

left to right main seq white dwarf supergiant giant

Refraction is caused by

light changing speed as it enters a new medium

Sort each graph into the bin describing how the data depends on the independent variable.

linear long close tg

The following graph shows the relative abundances of elements in our Solar System. Use the information in the graph to rank the elements in order from least to most abundant.

lithium iron carbon oxygen helium hydrogen

If you went to Mars, your weight would be

lower because Mars has lower mass and a smaller radius that together produce a lower gravitational force.

Based on your observations of the H-R diagram and what you have learned of the balance between gravity and pressure, sort each stage of a star's life below in order of increasing energy produced by the peak of its nuclear reactions.

lowest energy main sequence horizontal branch red giant asymptotic giant branch highest energy

The following are all potential explanations for the motion of sailing rocks, but not all of them are scientific hypotheses given the rules listed above. Which ones are not scientific hypotheses?

magic God ghosts

Sunspots, flares, prominences, and coronal mass ejections are all caused by

magnetic activity on the Sun.

Recall that conservation of angular momentum causes collapsing objects to rotate faster. With that in mind, sort the following objects in order of the rotational speed you would expect them to have when they first form, from slowest to fastest.

main sequence white dwarf neutron star black hole

Improved resolution is helpful to astronomers because it enables them to view

many objects close together, very distant objects, and small features of an object.

What is the single most important property of a star that will determine its evolution?

mass

The following infrared image shows part of the plane of the Milky Way Galaxy. Identify the region where a molecular cloud (think: dense and cold) will eventually result in the formation of new stars and planets.

middle

Now, rank the same objects by increasing temperature. For spherical objects, use the surface temperature.

molecular interstellar protostar star intercloud

Drag each label denoting length of time it takes light to travel from one location to another to the correct target.

moon earth 1.2 sec earth sun 8.5 min pluto star 4.3 years milky way 100,000 yrs

As a blackbody becomes hotter, it also becomes __________ and __________.

more luminous; bluer

Stars radiate like black bodies. Using the information given in the figure, this would mean that hotter stars emit __________ radiation __________ wavelengths, and their continuous spectra would peak at __________ wavelengths.

more, over all, shorter

The physical model of the Sun's interior has been confirmed by observations of

neutrinos and seismic vibrations.

The solar neutrino problem pointed to a fundamental gap in our knowledge of

neutrinos.

What phase is the Moon in when you initially open the simulation?

new

Each image shown depicts how light travels inside a particular type of telescope. Analyze each image and identify which type of telescope it is.

newt tube, cass less lines, ref more lines

The following image is a cross section of an asymptotic giant branch star. Place each label in the correct position on the image.

nonburning carbon burning helium burning hydrogen nonburning hydrogen

The following image is a cross section of a red giant star. Place each label in the correct position on the image.

nonburning helium burning hydrogen nonburning hydrogen

What time of day is it for the person shown on the Earth when you intially open this simulation?

noon

Based on this information, determine where you would expect to find Polaris in your local sky when you are standing at the equator.

north

To the right of the following figure are two labels: "pulsar observed" and "pulsar not observed." Click and drag each one to the appropriate target below the pulsar where an observer would be standing and see what is described.

not observed

Sort each scenario into the category indicating whether or not the car is accelerating.

not accelerating constant speed & velocity

An empirical science is one that is based on

observed data.

Astronomers determined the composition of the interstellar medium from

observing its emission and absorption lines.

The cosmological principle states that

on a large scale, the universe is the same everywhere at a given time.

Two stars are of equal luminosity. Star A is 3 times as far from you as star B. Star A appears _________ star B.

one-ninth as bright as

If the star Polaris has an altitude of 35°, then we know that

our latitude is 35° north.

As the core collapses, the neutrons hit this limit in density, and a new, extremely strong outward pressure called neutron degeneracy pressure appears. What effect might this have on the material outside the neutron degenerate core, which was previously collapsing under gravity?

outward

Which of Galileo's astronomical observations were best explained by a heliocentric model?

phases of Venus moons of Jupiter

If we were to take a snapshot of where the photons are inside the Sun, and which direction they are traveling, we would find that

photons are traveling in all directions.

What surrounds the object at the center?

planetary nebula

Kepler's second law says that

planets move fastest when they are closest to the Sun.

Hydrostatic equilibrium in the Sun means that

pressure balances the weight of overlying layers

The structure of the Sun is determined by both the balance between the forces due to _______ and gravity and the balance between energy generation and energy _______.

pressure; loss

Rank each color of light according to how much will be transmitted through to the other side of the cloud. Use the scroll bar to see all answer and placement options.

purple, blue, green, yellow, orange, red, IR

Which of the following can be observed from Earth's surface?

radio waves visible light

This activity will involve working with the entire electromagnetic spectrum (light!). It is the particles of light—the photons—that carry the energy. (Light can act as a wave or as a particle.) In preparation for the activity in your workbook, you need to rank the regions of the spectrum based on the energy associated with the wavelengths, from lowest to highest energy.

radio, infrared, visible, ultraviolet, xray

In the video, the loaded car accelerated less than the unloaded car when the same force was applied. This was noticeable because the loaded car

reached the end of the track more slowly. was traveling less quickly after a little time had passed.

Place the main-sequence lifetime of each of the following stars in order from shortest to longest.

short rigel can ach cap sir sun

Photons and particles that originate in the Sun reach Earth in a wide range of time intervals. Place these in order of their travel times.

shortest photosphere, neutrino, coronal, core

A high-mass star burns through a succession of heavier elements, after running out of hydrogen for nuclear fusion. Arrange these elements in order of the length of the stage during which the star burns.

si o ne c he

Match the absorption spectrum to the correct orientation of the stars. Assume that we are viewing the system from the bottom of each figure.

skinny right, center, skinny left

When light enters a medium from space it

slows down.

The Sun is part of

solar system < Milky Way Galaxy < universe

The Crab Nebula, a supernova remnant located in the constellation of Taurus, has been observed by many different telescopes, both ground-based and space-based. Following are four images of the nebula covering different wavelength regions of the spectrum. Separate the images on the basis of which ones had to be taken by a space-based telescope because the atmosphere is opaque at those wavelengths.

space based: UV and xray ground based: radio and optical

When we say that the universe is expanding, we are actually saying

space itself is expanding, carrying clusters of galaxies farther and farther apart.

Label the positions in the Earth's orbit with the appropriate day in the Northern Hemisphere. In the diagram shown, north is up and south is down. The direction of the Earth's axial tilt is exaggerated.

spring summer winter fall

Place the following steps that lead some low-mass stars in binary systems to become novae or supernovae in the correct order. Note that the first step is given.

star 1 (the more massive) star 1 fills star 2 gains a white dwarf orbits star 2 fills the white dwarf becomes

Order the steps in the scientific method by dragging each label to the corresponding target.

start w suggest make perform

Rank the objects in terms of the gravitational force on them, from smallest to largest.

styrofoam apple gold

Sort the following methods into whether or not it would work to detect the parallax shift of the object.

successful: launch a satellite combine images make simultaneous would not work: observe the moon

Rank the images of a star's changing interior from earliest to latest stage in its evolutionary sequence.

sun yellow hazy white blue middle small blue mid surround by yellow big blue mid white blue white mid small circle w haze

Rank the following classifications of stars from those that contribute the most light to the brightness of distant galaxies to those that contribute the least.

supergiant horizontal G K

When photodisintegration starts in a star, a process begins that always results in a

supernova

The time it takes for a planet to come back to the same position relative to the Sun is called its __________ period.

synodic

When less energy is radiated from a terrestrial planet, its __________ increases until a new __________ is achieved.

temperature; equilibrium

When we discuss continuous radiation, we are talking about electromagnetic radiation (light)

that varies smoothly in a predictable pattern over a wide range of wavelengths.

Newton's second law of motion states that

the acceleration of an object is proportional to the net force acting on it.

When we talk about the Big Bang, we are actually explaining

the beginning and evolution of all of space and all of time.

Based on this fact, what can we find from the wavelengths of absorption lines seen in the spectrum of a star?

the composition of any gas between the light-emitting "surface" of the star and the observer

The tilt of Earth's axis causes the seasons because

the days are longer the rays of light

Consider this information, and choose the property below that Type Ia supernova can help us measure.

the distance to a galaxy

A planetary nebula forms from

the ejection of mass from a low-mass star

The energy required to begin nuclear fusion in a protostar comes from

the gravitational potential energy of the protostar.

From your observations of these spectra, which wavelengths would be best to observe objects in order to get a view that is the least obstructed by interstellar extinction?

the longest wavelengths possible

The red giant branch is nearly vertical on the H-R diagram because:

the luminosity rises, but the temperature is nearly constant.

When radiation from an object passes through the interstellar medium

the object appears redder and dimmer.

The surface of the Sun appears sharp in visible light because

the photosphere is thin compared to the other layers of the Sun.

The advantage of an interferometer is that

the resolution is dramatically increased

The cosmological principle says that

the rules that govern the universe are the same everywhere.

Compared to your mass on Earth, on the Moon your mass would be

the same; mass doesn't change.

Which of the following factors does not directly influence the temperature of a planet?

the size of the planet

Post-main-sequence stars lose up to 50 percent of their mass because

the star swells until the surface gravity is too weak to hold material.

Which of the following properties must be measured to determine the masses of stars in a typical binary system?

the velocities of the two stars the period of the orbits of the two stars the average separation between the two stars

Sunspots appear dark because

they are cooler than their surroundings.

All large astronomical telescopes are reflectors because

they are not as heavy.they can be shorter.chromatic aberration is minimized.

The position of the larger member of a binary system is shown here, along with the orbital path of the second. Locate the companion star based on the current position of the larger star. Companion star

top

Place each star at its correct position on the H-R diagram. Main sequence starWhite dwarfSupergiantGiant

top c a d b

Astronomers use two points in Earth's orbit to get the best possible parallax measurement. Even better measurements would be possible with observations from

two points in the orbit of Mars, separated by half a Martian year.

Using the graph, identify the characteristics of either Type II or Type Ia.

type ii - developed from single massive star - as bright as several milli suns at peak - luminosity abruptly lessens after 75 days type ia - as bright as 10 billi suns at peak - devel binary star system - luminosity steadily decreases after 40 days

Based on all of this, which type of light will be most affected by interstellar extinction?

ultraviolet

The unique patterns that appear in spectra of light give astronomers clues about the objects that are reflecting, absorbing, or emitting that light. We use unique patterns in our lives, some in a specialized sense and others in a generalized way. Sort the following items into unique or not unique patterns.

unique: food bar codes dna analysis fingerprints not unique: housing developments astrological forecasts

Label the four general luminosity classes of stars on the H-R diagram.

up down d super c giant b main a white

Sort the listed wavelengths of light by region of the electromagnetic spectrum. The wavelengths in micrometers (10-6 m) are given in μm units.

uv 121 v 656 infr 12 1000 6

Drag each phase of the Moon to its correct location during that phase.

wax gib first q wax cres wan gib third q wan cres

Understanding in science means that

we are able to connect facts through an underlying idea.

The "second" high tide is caused by

weaker gravity pulling on Earth on the side opposite the Moon.

The following images show the evolution of two close binary stars. Rank them from earliest to latest stage in this system.

white orange red blue cloud

What is at the center of the image?

white dwarf

The luminosity of a star changes throughout its life. For a star of 1 MSun, rank the stages of its life according to its luminosity at each stage.

white dwarf on the main protostar horizontal red giant

Rank these images of the interior of an evolving high-mass main-sequence star from earliest to latest stage.

white middle blue middle grey middle yellow middle

If Earth's axis were tilted by 45°, instead of its actual tilt, how would the seasons be different than they are currently?

winters colder

Based on the above graph, which of these types of light from astronomical sources are not observable from the ground?

x-ray gamma ray infrared at 100 micrometer (10-4 m) ultraviolet at 100 nm

Five different telescopes have taken images of the Crab Nebula, a supernova remnant located in the constellation of Taurus. Following are those five images showing the energy output of the nebula at five different wavelengths. Rank them from the highest to lowest energy being emitted by various parts of the nebula.

xray UV opt infrared radio

Kepler's third law tells us that:

𝑝^2=𝑎^3

Rank the following in order of increasing size.

(smallest) earth, sun, solar system, milky way, virgo supercluster, universe (largest)

What is the eccentricity of a circular orbit?

Rank the tides that occur at each date in order from strongest to weakest.

1. full moon in January 2. new moon in July 3. first quarter moon in July 4. third quarter moon in January

The following astronomical events led to the formation of you. Place them in order of their occurrence over astronomical time.

1. hydrogen 2. stars are born 3. stars die 4. enriched dust 5. the sun and planets

Rank the following in order of size, from smallest to largest.

1. radius of earth 2. a light-minute 3. distance from earth to sun 4. a light-hour 5. the radius of the solar system 6. a light-year

There are many perfectly valid subjects that cannot be studied using the scientific method. Which of the following cannot be studied in a scientific way?

religion art the relative tastiness of various foods

Day and night are caused by the

rotation of the Earth on its axis.

An observer sees the Moon in full phase, __________________, at 6 A.M.

setting in the west

Suppose that you drop the following objects (all of the same shape and size) off of a tall tower.Rank the objects in terms of the gravitational force on them, from smallest to largest.

styrofoam apple, apple, gold apple

We always see the same side of the Moon because

the Moon rotates once each revolution.

On the vernal and autumnal equinoxes

the Sun rises due east and sets due west. the Sun is located on the celestial equator. the entire Earth has 12 hours of daylight and 12 hours of darkness.

You do not see eclipses every month because

the Sun, Earth, and the Moon line up only about twice a year.

Subsequent semi-diurnal (twice daily) tides happen precisely once every 12 hours and 25 minutes. Given what you know of the motions of the Earth and Moon, where is this extra 25 minutes likely coming from?

the orbit of the Moon around the Earth

The seasons are caused by

the tilt of the Earth's axis.

Label each marked location on the celestial sphere with the term that best describes it. The Earth is oriented in the standard way, with north up and south down.

top A right C left D bottom B

As two objects orbit one another, they are always

on opposite sides of the center of mass, traveling in opposite directions in space.

You see the first quarter Moon on the meridian. Where is the Sun?

on the western horizon

"This natural phenomenon was caused by extraterrestrial visitors who leave no measurable trace of their presence."

Hypotheses must be verifiable.

Examine the following figure, which demonstrates star trails that would be visible in a photo centered on the North Star (Polaris) when the camera's shutter is left open to reveal the path the stars are taking as they move during part of one night. Which of the following best describes your observations?

All of the stars move in a counterclockwise path around Polaris. The stars closest to Polaris move in smaller circles.

The process of making predictions and testing scientific models never ends, as there is always the possibility that some future experiment or observation will show that a previously well-accepted model doesn't actually work under all circumstances. However, if a hypothesis is backed up by a very large body of evidence and has never failed a test, it may be elevated to the status of a theory. According to the scientific method, choose all of the following statements that are correct.

Why is there an angle between the ecliptic and the celestial equator?

Earth's axis is tilted with respect to its orbit.

Imagine that Earth were in a stable orbit at its current distance from the Sun, but around a different star that had twice the mass of the Sun. Which of the following would have to be true?

Earth's year would be shorter.

"This model is proven to be correct because it makes accurate predictions 75 percent of the time."

Hypotheses must be abandoned or revised if they fail a single test.

How does the changing position of the Sun on the ecliptic affect our view of the Sun in our local sky at different locations on Earth?In this interactive figure (Flash required) investigate how the path of the Sun changes in the local sky of a person at various latitudes on Earth. Then choose the following statements that match your observations. (See the Hint if you need tips on how to use the figure.)

In the Northern Hemisphere, the Sun is lower in the sky in December than it is in June. At latitudes closer to the poles, the difference in the Sun's illumination throughout the year is more extreme. In the Northern Hemisphere, the length of the day is shorter in December than it is in June.

In the Northern Hemisphere, the Sun is lower in the sky in December than it is in June. In the Northern Hemisphere, the length of the day is shorter in December than it is in June. At latitudes closer to the poles, the difference in the Sun's illumination throughout the year is more extreme.

Suppose you read on the Web that a new planet has been found. Its average speed in its orbit is 33 kilometers per second (km/s). When it is closest to its star, it moves at 31 km/s, and when it is farthest from its star, it moves at 35 km/s. This story is in error because

Kepler's second law says the planet must move fastest when it is closest, notwhen it is farthest away.

There is evidence that wind can set the rocks moving when the ground becomes muddy or when thin layers of ice form beneath the rocks. This scenario has not been falsified by any tests conducted so far, and it is currently the favored explanation within the scientific community. What is the next step in the scientific process?

Make further predictions about this hypothesis and conduct more tests, abandoning or revising the hypothesis if any of the tests are failed.

Once we have come up with a number of plausible hypotheses to explain the "sailing rocks" phenomenon shown, what is the next step we should take, according to the scientific method?

Make predictions for each hypothesis, which will be observed if that hypothesis is correct.

What are the two pieces of information that must be considered to explain the seasons?

Sunlight is more concentrated in the Northern Hemisphere in July. The Sun rises earlier and sets later in July in the Northern Hemisphere.

Newton determined that the force of gravity on an object is proportional to its mass, causing its mass to be canceled out (Newton's second law) and resulting in a constant acceleration. If the laws of physics are universal, then Newton should be able to apply his discoveries about gravity on Earth to the motion of the planets in our Solar System. Newton's third law says that for every force there is an equal reaction force in the opposite direction. What does this imply about the force of gravity associated with a person standing on the Earth?

The Earth's gravity pulls downward on the person, and the person's gravity pulls upward on the Earth.

If these tidal forces naturally cause synchronous rotation for each object, why is the Moon currently in synchronous rotation with the Earth, but the Earth is not in synchronous rotation with the Moon?

The Moon is much less massive than the Earth, so it will take longer for it to slow the Earth into synchronous rotation.

The gravity of this off-center bulge has an effect on the Moon. Study the above figure, and choose the statement below that follows from it.

The Moon used to be closer to Earth than it is now.

During the day, the Sun is too bright for us to see where it is located with respect to the constellations, but we can use our observations of stars at night to figure this out. Based on the way stars shift position over the course of a year, your knowledge of how the time of day is defined, and the fact that the same constellations are seen at the same place in the sky at the same time of night on a given day of the year, which of the following is most likely correct?

The Sun appears to move across the constellations over the course of a year, ending where it started with respect to the background stars by the end of that period.

Assuming you are in the Northern Hemisphere, how would you expect the location of the Sun in your local sky at noon to differ from season to season?

The Sun will appear to be higher above the southern horizon in the summer than in the winter.

Isaac Newton developed a theory of gravity by first considering Galileo's experiment of dropping objects of different masses from the Leaning Tower of Pisa. Galileo found that, when air resistance is negligible, all objects took the same amount of time to hit the ground when dropped from the top of the tower.

The acceleration of all objects dropped from the tower is the same.

The stars closest to Polaris move in smaller circles. All of the stars move in a counterclockwise path around Polaris.

If the Moon had twice the mass that it does, how would the strength of the lunar tides change?

The highs would be higher and the lows would be lower.

Is the hypothesis that the seasons are caused by a variable distance between the Earth and the Sun verified or falsified by the evidence?

The hypothesis is falsified because some of the evidence is against it.

What does the change in the period with respect to the eccentricity tell you about the dependence of the period on the eccentricity?

The period does not depend on the eccentricity.

From our point of view on Earth, it feels as if we are stationary and the celestial sphere and Sun are all rotating around us. In actuality, however, the Earth is moving, rotating on an axis that is tilted with respect to the orbit it takes around the Sun.Open the AstroTour called "The Earth Spins and Revolves." Watch the Introduction, and the first half of the Explanation (up until the interactive part). Then, choose one of the following conclusions that best explains the cause of the shift from day to night.

The shift from day to night is caused by the rotation of the Earth around its axis.

Then, choose one of the following conclusions that best explains the cause of the shift from day to night.

The shift from day to night is caused by the rotation of the Earth around its axis.

Count the number of squares in the yellow area and in the red area. You will need to decide what to do with fractional squares.Are the areas the same? Should they be?

Yes, yes

If Earth's axis were tilted by 45°, instead of its actual tilt, how would the seasons be different than they are currently?

Winters would be colder.

Let the simulation run from its initial setting until the Moon reaches waxing crescent and then pause it.At which of these times would the person shown on Earth be able to observe this waxing crescent Moon?

after sunset

For a pair of objects, the center of mass is located

along the line between the two objects, closer to the more massive object.

Where on Earth can you stand and, over the entire year, see the entire sky?

at the equator

If you were standing at Earth's North Pole, where would you see the north celestial pole relative to your zenith?

at the zenith

Kepler's second law says that if a planet is in an elliptical orbit around a star, then the planet moves fastest when the planet is

closest to the star.

Arrange the observer and the Moon so that it is approximately 6:00 P.M. (sunset) for the observer and the Moon is just rising on the eastern horizon. What is the phase of the Moon?

full

You see the Moon rising, just as the Sun is setting. What phase is the Moon in?

full

Where is the Moon in the person's sky when you initially open up the simulation?

high in the south

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