Exam 2 - Introduction to the Solar System

What is the solar system?

The Sun together with the planets orbiting the Sun, moons orbiting the planets, asteroids orbiting the Sun, and other minor objects.

What are the eight planers in order?

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune

What are the four inner planets?

Mercury, Venus, Earth, Mars

What are the four inner planets classified as?

Terrestrial planets

What are the characteristics of terrestrial planets?

Small, dense, made of metal and rock, have few or no moons, no rings, and rotate slowly

What are the four outer planets?

Jupiter, Saturn, Uranus, Neptune

What are the four outer planets classified as?

Jovian planets

What are the characteristics of jovian planets?

Large, low-density, primarily made of hydrogen and helium gas, have many moons, rings, and rotate quickly

What is another term for Jovian planets?

Gas giant planets because they are large and tenuous

What is tenuous?

Composed primarily of gas

What do the 8 planets orbit the Sun on?

Ecliptic Plane

What does the ecliptic plane do to the Solar System?

It makes it flat and the inclinations small

What is the shape the 8 planets orbit around the sun in?

Roughly circular (only slightly elliptical)

What direction do all the planets move in when observed from above?

Counterclockwise

True or False: All 8 planets orbit the sun in the same direction

True

True or False: All 8 planets rotate in the same direction

False

When and how was the Solar System formed?

4.6 billion years ago from a diffuse nebula

What is a diffuse nebula?

giant cloud of gas composed mostly of hydrogen and helium with small amounts of all the other atoms on the Periodic Table

What are examples of different forces that push the gases within the diffuse nebula?

Thermal pressures, gravitational forces, magnetic pressures, and cosmic rays (ultra-high-energy particles)

True or False: Are all these different forces comparable in strength with each other in interstellar space?

True

What is interstellar space?

the space between star systems

What happens when various forces push gases in different directions?

It creates regions of varying density within a diffuse nebula

What happens when a particular region becomes dense enough?

Its self-gravity dominates all the other forces which causes it to collapse under its weight.

What does the collapse lead to?

It leads to the formation of the Sun at the center.

What happens as the surrounding cloud continues to collapse?

Particle collisions become more frequent and the colliding matter tends to stick together and gradually form larger masses

What does the conservation of translational (linear) momentum to the condensing collapsing cloud of gas and dust?

It reduces the motion of larger masses along the direction of the axis of the total angular momentum

What does the conservation of energy do to the cloud?

It causes particles to heat up as collisions are converted by kinetic energy into thermal energy.

What does the law of conservation of angular momentum do to the cloud?

It leads to more circular orbits as random motions are evened out/

What do all the physical laws do to the collapsing material?

It flattens it into a rotating, circular protoplanetary disk

What is a protoplanetary disk?

circular, rotating disk perpendicular to the axis of total angular movement of the forming of the Solar System

What happened in the first couple of hundred million years after the protoplanetary disk formed?

Frequent, sticky, heat-generating collisions caused particles to merge into larger masses during the heavy bombardment period

What happened to the inner protoplanetary disk?

It allowed only metal and rock to condense, being hotter due to its proximity to the Sun

What happened to the cool outer protoplanetary disk?

It allowed additional materials, including hydrogen and helium, to accumulate

What happened to the forming planetesimals?

They grew by accretion as they collided with the surrounding material along their orbits; as they grew larger, their self-gravity forced them into spherical shapes

What are planets and major celestial bodies named after?

Ancient Roman mythological gods or Greek equivalents

What is the Sun named after?

Sol or Helios

What is Mercury named after?

Roman messenger of the gods, or Hermes

What is Venus named after?

Roman goddess of love, or Aphrodite

What is Earth named after?

Terra, or Gaia

What is Earth's Moon named after?

Luna the Roman goddess of the moon or Selene

What is Mars named after?

Roman god of war, or Ares

What are the two moons of Mars named after?

Phobos and Deimos (fear and panic), twin sons of the god of war

What is Jupiter named after?

Roman king of the gods, or Zeus

What is Saturn named after?

The youngest of the titans and father to Jupiter (Zeus), or Kronos

What is the largest moon of Saturn named after?

Titan since Saturn was the youngest of the Titans

What is Uranus named after?

Greek god of the sky, or Caelus, was the father of the titans

What is Neptune named after?

Roman god of the sea, or Poseidon

What is the largest moon of Neptune?

Triton is named after the son of the god of the sea, Neptune

What is Pluto named after?

Roman god of the underworld, or Hades

What is the largest moon of Pluto named after?

Charon, boatman who ferried souls cross the river Styx to the underworld

What is the astronomical symbol of the Sun?

☉

What is the astronomical symbol of Mercury?

☿

What is the astronomical symbol of Venus?

♀

What is the astronomical symbol of Earth?

⊕

What is the astronomical symbol of Earth's Moon?

☽︎

What is the astronomical symbol of Mars?

♂

What is the astronomical symbol of Jupiter?

♃

What is the astronomical symbol of Saturn?

♄

What is the astronomical symbol of Uranus?

⛢

What is the astronomical symbol of Neptune?

♆