Astronomy Exam 2

Continental drift

large-scale horizontal movements of continents relative to one another and to the ocean basins during one or more episodes of geologic time

1. The least dense planet: 2. The largest moon in the solar system 3. The smallest planet 4. The moon with the thickest atmosphere

1. Saturn 2. Ganymede 3. Mercury 4. Titan

Meteoroids-Meteor/meteorite A)Collide with Earth's atmosphere B)If an object makes it through the atmosphere and lands on the surface of the Earth

A-Meteor B-Meteorite

How do asteroids and comets differ?

Asteroids: are composed primarily of rock and metal and reside in the inner part of the solar system with a greater density. Comets are typically icy objects that come from the outer and become visible as they approach the sun ice sublimates.

Mountain building

Created when 2 tectonic plates push against each other raising the earth's surface

Frozen water exists on the lunar surface primarily in which location? Why?

Deep craters on the Moon's south pole: Parts of these craters are permanently in shadow and therefore do not receive enough energy from the Sun to evaporate the ice and escape into space.

Compare the current atmospheres of Earth, Venus, and Mars in terms of composition, thickness (and pressure at the surface), and the greenhouse effect.

Earth's atmosphere is about 4/5 nitrogen and 1/5 oxygen; Venus's atmosphere is mostly carbon dioxide, with a pressure about 90 times higher than Earth's. Mars' atmosphere is also mostly carbon dioxide, with a pressure only about one hundredth that of Earth. Venus has had an ongoing runaway greenhouse effect, leading to extraordinarily high surface temperatures. Earth is presently seeing the greenhouse effect increase with higher levels of carbon dioxide in the atmosphere. Mars has had a "runaway refrigerator" effect leading to a thinner atmosphere and colder temperatures over time.

What is the source of Earth's magnetic field?

Electric currents in the conductive iron alloys of its core

Summarize the four main hypotheses for the origin of the Moon.

Fission hypothesis: suggests that the Moon was once part of Earth but separated early in their history. Sister hypothesis: proposes that the Moon formed together with, but independent of, Earth. Capture hypothesis: The moon formed elsewhere in the solar system and was later captured by Earth. The newer giant impact hypothesis: suggests that a Mars-sized object grazed Earth, ejecting material from both Earth and itself—material that condensed to form the Moon.

Which type of planets have the most moons? Where did these moons likely originate?

Giant Planets Moons originated from the small-body population during the formation of the solar system.

The mountains on the Moon were formed by what process?

Gigantic impacts during the Moon's young lifeThese impacts left huge inner craters surrounded by colossal rims that would later become mountain ranges.

What does a planet need in order to retain an atmosphere? How does an atmosphere affect the surface of a planet and the ability of life to exist?

Gravity- sufficient enough to create a dense atmosphere around it, so that it can retain heat coming from the sun.

Why is Mars red?

Iron minerals in the Martian soil oxidize, or rust, causing the soil and atmosphere to look red.

Why are asteroids and comets important to our understanding of solar system history?

It is believed that comets and asteroids are the relics of the material that formed the solar system

Which planet has the strongest magnetic field, and hence the largest magnetosphere? What is its source?

Jupiter

Why do meteors in a meteor shower appear to come from just one point in the sky?

Meteor shower particles are all traveling in parallel paths, at the same velocity, they will all appear to radiate from a single point in the sky to an observer below.

In what ways are meteorites different from meteors? What is the probable origin of each?

Meteorites are large enough to withstand the violent passage through Earth's atmosphere, whereas meteors burn up from the heat of friction. Meteors typically come from comets that have passed through the solar system; their solid material is freed when the ice is vaporized by the heat of the Sun. Most meteorites, on the other hand, are from asteroids or from debris kicked up on the Moon or Mars during an impact..

How are comets related to meteor showers?

Most meteor showers originate with particular comets that pass through the inner solar system and lose some of their solid material, which then goes into orbit along the comet's path.

Greenhouse effect

Natural situation in which heat is retained in Earth's atmosphere by carbon dioxide, methane, water vapor, and other gases

Which of the gas giants has the largest icy/rocky core compared to its overall size?

Neptune

What is, by far, the most abundant component of Earth's atmosphere?

Nitrogen

Describe the two types of comet tails and how each are formed.

Plasma tail: comprises electrons and ions that are ionized by the sun's ultraviolet radiation Dust tail consists of micrometer-scale particles. The dust tail is wide and slightly bent because of the pressure of the light from the sun and the orbital action of the comet's nucleus.

What are the seasons like on Jupiter?

Since Jupiter's spin axis is only tilted about 3° from the perpendicular, it does not experience seasons at all.

How do terrestrial and giant planets differ? List as many ways as you can think of.

Terrestrial- Closer to the sun, smaller, higher densities, silicates and metals. Giant- low densities, far from the sun, larger, no solid surface, more moons.

Give brief descriptions of both the Kuiper belt and the Oort cloud.

The Kuiper Belt is a "junkyard" of countless icy bodies left over from the solar system's formation. The Oort Cloud is a vast shell of billions of comets

Why does the moon not have an atmosphere?

The Moon's mass, and therefore its gravitational force, is not large enough to retain gases and volatile compounds. Therefore, any gases released on the Moon quickly escape into space.

Describe the solar nebula, and outline the sequence of events within the nebula that gave rise to the planetesimals.

The Sun and planets began to form in a rotating cloud of nebular gas and dust. These materials eventually clumped together with a hot protosun at the center and chunks of planetesimals rotating around it. Through repeated collisions, the planetesimals grew into protoplanets, and eventually the solar system came about.

Give a brief description of the asteroid belt.

The asteroid belt is a region of space between the orbits of Mars and Jupiter containing a few large minor planets and thousands of smaller bodies. These all have orbital periods ranging from 3.3 to 6 years.

Why do the upper levels of Neptune's atmosphere appear blue?

The gaseous molecules in Neptune's atmosphere scatter blue light, giving Neptune its color. The same process makes Earth's sky appear blue.

What characteristics do the worlds in our solar system have in common that lead astronomers to believe that they all formed from the same "mother cloud" (solar nebula)?

They generally rotate and revolve in the same direction and their orbits lie roughly in the same plane. The chemical makeup of the giant planets is similar to the sun.

Describe and compare the rings of Saturn and Uranus, including their possible origins.

The rings of Saturn form a complex system of particles and pieces of ice and are highly visible. They may have formed from one or more moons that broke up due to a collision. The rings of Uranus are thin and difficult to see. They are made of carbon and hydrocarbons.

What was the solar nebula like? Why did the Sun form at its center?

The solar nebula was a huge cloud of material made up of gas and dust. The sun formed at the center due to gravitational forces, caused that material to stick together, and once the mass and density increased sufficiently, nuclear fusion caused a star to form: the sun.

Explain the energy source that powers the volcanoes of Io.

The tidal energy that is generated by Jupiter and its other big moons.

Compare the properties of Titan's atmosphere with those of Earth's atmosphere.

Titan's atmosphere is made mostly of nitrogen, like Earth's, but with a surface pressure 50 percent higher than Earth's. Titan has clouds, rain, rivers, lakes and seas of liquid hydrocarbons like methane and ethane.

Describe the seasons on the planet Uranus.

Uranus's dramatic 98-degree tilt gives rise to the most extreme seasons in the solar system. For nearly 21 years, a quarter of the Uranian year, one pole is bathed in sunlight while the other exists in complete darkness

What is the composition of clouds on Mars?

Water ice and CO2 ice particles