Astro Exam 2 04-08 Homework Questions

Due to gravitational tidal forces from Earth, the Moon has a deformation of its shape known as a tidal bulge. Likewise, Earth has a tidal bulge owing to the Moon's gravity. The image choices show both tidal bulges, where the arrows denote the direction of gravitational attraction. Which image choice shows the correct relative alignments for the tidal bulges of both Earth and the Moon?

*Image with Earth Pointing right and moon pointing left*

Jovian Storms only

-Associated with oppositely-directed high-speed atmospheric flows -Hosted by rapidly-rotating planet

As astronomers continued to study Pluto and objects in the Kuiper belt, it became clear that Pluto has more in common with Kuiper belt objects than with the eight major planets in the solar system. With the discovery of Eris, an object even larger than Pluto, the International Astronomical Union introduced a new category of solar system objects called dwarf planets. Pluto was reclassified as a dwarf planet in 2006. Which of the following factors contributed to the evolution of scientific thinking that led to the reclassification of Pluto as a dwarf planet?

-Better technology led to improved understanding of objects in the solar system. -More precise observations provided new information about the nature of Pluto -Terminology and classifications changed as scientific understanding and knowledge evolved.

To be effective, a scientific theory must be continually tested. If observations and experiments favor it, a theory can be further developed and refined. If they do not, the theory must be reformulated or rejected. Comparing what you know about the predictions of each Moon formation theory, determine which of the following observations and experiments have been verified. Select all that apply.

-Earth has a large iron core; the Moon does not. -The mantles of Earth and the Moon have similar compositions. -Computer simulations predict that a collision between Earth and a Mars-sized object would produce a Moon-sized satellite with a stable orbit.

Below are two additional figures (Figure A and Figure B) that illustrate characteristics of the solar system. Select which property or properties are illustrated by each figure.

-Figure A: Primitive comets in the Oort cloud orbit the Sun with inclined orbits and reside at a great distance from the Sun. -Figure B: Planetary properties of the solar system are highly differentiated.

Both jovian and terrestrial storms

-Involve upwelling gasses -Involve circulating winds

Based on the evidence for the impact theory, what was the most probable order of events for the collision that led to the formation of the Moon? Rank the steps of the impact theory from earliest to latest. If two steps occurred at precisely the same moment, place one on top of the other.

-Iron core of Earth forms. -Mars-sized object collides with Earth -If the Mars-sized object has an iron core, most or all of it is left behind on Earth and merges with Earth's core. -The Moon forms out of rocky debris ejected from Earth during the collision.

Since the early 1990s, observations of the solar system beyond Neptune, where Pluto resides, have revealed numerous objects orbiting the Sun. This collection of objects is known as the Kuiper belt. More Kuiper belt objects are being discovered each year, providing astronomers with a better understanding of their physical and orbital properties. From the list below, identify which properties are characteristic of Kuiper belt objects.

-Kuiper belt objects have a low relative brightness when observed from Earth. -About 25%% of Kuiper belt objects have the same orbital period as Pluto. -Kuiper belt objects orbit the Sun at great distances. -Kuiper belt objects are small, icy bodies.

Consider the orbiting system around Saturn. Within close proximity to Saturn are rings of material that are composed of hundreds of thousands of small particles. Outside of the rings is a multitude of orbiting moons, ranging in size from tens of kilometers in diameter to thousands of kilometers. Select the statements that correctly describe what would happen if a large moon passed inside of the Roche limit and what does happen to small clumps of material inside Saturn's rings.

-Material inside the Roche limit will be restricted by tidal forces from forming into larger clumps or moons -If a large moon passed inside of the Roche limit it would be torn apart by Saturn's large tidal forces.

Saturn's rings show signs of being an active and dynamic system, with many features changing on short timescales. Scientists believe that the rings are quite young. If the rings are indeed so young, then either they are the result of a relatively recent, possibly catastrophic event in the planet's system, or they are replenished from time to time. Select the statements that could explain how Saturn's rings were created or are replenished.

-Meteoritic impacts chip off debris from the moons just outside the Roche limit. -A large comet collides with a moon near the Roche limit, breaking apart the moon. -A collision occurs between two moons near the Roche limit, shattering both. -Medium-sized moons are torn apart as they pass into Saturn's Roche limit

Consider the figure below and determine which characteristics of the solar system it illustrates.

-Mostly the direction of planetary rotation is the same as the direction of the Sun's rotation. -Mostly satellite orbital direction is the same as the satellites' parent planet rotational direction. -Planets orbit in the same direction as the Sun rotates on its axis.

Jupiter's differential rotation and complex atmospheric structure induce turbulent storms, such as the Great Red Spot. Identify the statements that correctly describe the characteristics of storm systems on Jupiter.

-On Jupiter, the larger the storm, the longer it can last. -Individual storm systems can interact, resulting in the storm growing or fading out. -Storms are localized features, confined and powered by zonal flow.

A few of the characteristics that a model of solar system formation must explain are illustrated in the figure below; choose which one(s) apply to this figure?

-Planets are comparatively isolated in space. -A collection of asteroid-sized objects orbits beyond Neptune in the Kuiper belt. -Planets orbit with nearly circular orbits.

Terrestrial storms only

-Powered by solar radiation -Short-lived (hours to days)

All four jovian planets have storm systems in their atmospheres. From the list below, select the atmospheric characteristics that are found on all four jovian planets. Select all that apply

-Rapid Winds -Banded atmospheric patterns consisting of light colored zones and dark colored belts -Small oval-shaped storm systems

According to the current understanding of Earth's magnetic field and how magnetic fields are generated, which two components in Earth's internal structure are required in order to generate a magnetic field? Select all that apply.

-Rapidly rotating core -Conducting liquid core

Which of the following predictions should be true if the Capture Theory is correct?

-The Moon and Earth should have completely different compositions. -Mathematical models would need to predict that the capture of a Moon-sized satellite would be likely in Earth's early history.

Which of the following predictions should be true if the Impact Theory is correct?

-The Moon and Earth should have similar mantle compositions, but other parts of their compositions should be dissimilar. -Computer simulations would need to predict that a collision between Earth and a Mars-sized object would produce a Moon-sized satellite with a stable orbit.

Formation of Terrestrial Planets

-accreted from planetesimals of rock and metal -surfaces dramatically altered during the heavy bombardment

Characteristics of Earth atmosphere

-atmosphere composed primarily of nitrogen -ultraviolet-absorbingstratosphere

In the image, a scarp known as the Discovery Scarp is shown cutting across several craters. Unlike Earth, Mercury has no plate tectonics or fault lines, so astronomers theorize that the scarp was produced by a process that involved a cooling and contracting of Mercury's surface. Rank the surface features by their relative ages from oldest to youngest.

-crater A -crater B -scarp

Characteristics of Mars atmosphere

-extremely low density atmosphere -global dust storms

Comets

-form a coma when near the Sun -visible in the sky as a fuzzy patch of light that rises and sets with the stars -most are located either in Kuiper belt or Oort cloud

Formation of Jovian Planets

-formed in a region of the solar system with lower orbital speeds -formed in regions cold enough for water to freeze -accreted from icy planetesimals -large moons formed in surrounding disks of material -ejected icy planetesimals that are now Oort cloud comets

Jovian Planets

-primarily composed of hydrogen, helium, and hydrogen compounds -low average density -numerous orbiting moons -extensive ring systems

Terrestrial Planets

-solid, rocky surface -small size -located within the inner solar system

Characteristics of Venus atmosphere

-sulfuric acid clouds -almost no surface winds -runawaygreenhouse effect

After the discovery of Uranus, astronomers calculated its orbit and predicted its position in the sky using Kepler's laws of planetary motion, which had been known since the early 17th century. However, they soon discovered a small discrepancy between the predicted and actual positions of Uranus. As a scientist, what should you do when presented with such a conflict between prediction and observation?

-think about what else might cause the observed discrepancy -verify that your observations are correct -consider that Uranus may not be a planet -consider that Uranus may not be a planetconsider whether Kepler's laws need to be modified to account for the new observations

Asteroids

-typically orbit the Sun at approximately 3 AU -compositions similar to that of the terrestrial planets

Meteors

-visible in the sky as a bright streak of light for only a few seconds -dust particles entering Earth's atmosphere at high speed

Which of the following features on Mars is/are volcanic in origin?

Alba Mons

Some jovian storms such as Jupiter's Great Red Spot have been observed to last for years to decades. The reason why these large storms live so long is not well understood, but astronomers have begun to monitor these storms more closely with spacecraft and have discovered some common properties among them. Which of the following properties does not contribute to the longevity of large jovian storms?

Atmosphere composed mainly of hydrogen and helium

What seems to be the most common feature of the landing sites of the various Mars missions?

Evidence for water at some point in Mars' history

True or false, after investigating a great many features on the surface of Mars, we can say that all Martian geology, other than impact cratering, is deep in the past.

False

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.

Consider the figure below and determine which property or properties of the solar system it illustrates.

Planets orbit in virtually the same plane.

Pluto was first observed in 1930, and its largest moon, Charon, was discovered in 1978. A few years after Charon's discovery, astronomers were able to observe a series of eclipses as Pluto and Charon passed in front of one another. By studying how the brightness of Pluto and Charon changed as they eclipsed each other, astronomers were able to measure the masses and radii of both Pluto and its moon. What did these measurements imply about the average densities of Pluto and Charon?

Pluto and Charon have average densities that are expected for objects made mostly of water ice.

Which of the following predictions should be true if the Confirmation Theory is correct?

The Moon and Earth should have very similar compositions.

Which of the following locations does not show direct evidence of a liquid water past on Mars?

Valles Marineris

Scientists expected Venus to have a large amount of water. However, little detectable water has been found anywhere on Venus, either on its surface or in its atmosphere. Water, like carbon dioxide, is a greenhouse gas. What is NOT a reason for Venus to now be so dry?

Venus never had any water because it is too close to the Sun.

The magnetic fields in all planets are generated by the dynamo effect, caused by rapidly rotating and conducting material flowing in the interiors of the planets. We have just seen that all four of the jovian planets have magnetic fields. Earth also has a planetary magnetic field, but Venus does not, although it is very similar to Earth in mass. Which of the following would be a reason why Venus does not have a magnetic field?

Venus's very slow rotation rate does not allow a magnetic field to form.

Estimate the fractions of Earth's volume represented by the crust.

about 1%

On the basis of the data presented in the text, estimate the fractions of Earth's volume represented by the inner core.

about 1%

Estimate the fractions of Earth's volume represented by the outer core.

about 15%

Estimate the fractions of Earth's volume represented by the mantle.

about 80%

The ________________ states that the Moon formed far from Earth and later became gravitationally bound by Earth after a close encounter.

capture theory

According to the ____________________, Earth and the Moon formed at about the same time out of the same pre-planetary matter.

coformation (or sister) theory

A glancing collision between a large, Mars-sized object and a youthful, molten Earth led to formation of the Moon according to the _________________.

impact theory

Saturn's rings look bright because __________.

light from the Sun reflects off the material in the rings

Saturn's rings are composed of __________.

lots of individual particles of ice and rock