Phys/AST 113 - The Solar System - Unit 3 Review

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

The 8 planets in order

Ellipses

Orbits are _____________ (shape)

Counterclockwise

Orbits move _______________________ (direction)

Terrestrial Planets

Rocky, inner solar system, slow rotation, and few or no moons; Mercury, Venus, Earth, Mars

Jovian (Gaseous) planets

Gaseous, outer solar system, rapid rotation, rings, and many moons; Jupiter, Saturn, Uranus, Neptune

Dwarf planet

an object that only fulfills the first two things that makes a planet a planet (orbits the sun, large enough for its own gravity to make it round)

Small solar system body

an asteroid, comet, or other object that orbits a star (the Sun) but is too small to qualify as a planet or dwarf planet

Asteroids

rocky objects which orbit between Mars and Jupiter; asteroid belt

Comets

chunks of very dirty ice that come from beyond the orbit of Neptune

Kuiper Belt

- Region that extends from around Neptune to about 500 AU from the Sun.
- Some comets come here.
- Pluto and some dwarf planets are found here.
- Icy and rocky bodies.
- More massive than asteroid belt.

Oort Cloud

- Proposed massive sphere of cometary material from 50,000 to 100,000 AU from Sun.
- Leftover material (asteroids and comets) from formation of solar system.
- Source of unbound comets.

5

How many dwarf planets orbit our Sun?

8

How many classical planets orbit the Sun?

Venus (243 Earth days)

Which planet has the longest day (slowest rotation)?

Jupiter

Which planet has the highest mass?

Venus

Which planet has the highest surface temperature?

Earth

Which planet has the highest density?

Mercury

Which planet orbits the Sun the fastest?

Jupiter

On which planet would you weigh the most?

Big Bang

After the _____ _____, only the lightest elements emerged

Hydrogen and Helium

What two elements were the first stars primarily made of?

Heavier elements

The first stars processed the hydrogen and helium to make (carbon, oxygen, etc.):

Giant molecular clouds

cold, massive clouds of gas and a little bit of dust

Hydrogen

Element with the highest percentage in Giant Molecular Clouds (71%)

Collapsing

First stage of star formation

Protostar

A contracting cloud of gas and dust; the earliest stage of a star's life; the greatest concentration of matter at the center

Kelvin-Helmholtz contraction

As material falls inward, it gains speed, collides with other material, and heats up. The whole nebula heats up.

Pressure, temperature

Eventually, the _____________ and ______________________ at the center get high enough for hydrogen to be converted into helium. A star is born!

The Sun

A planet is a body that orbits:

Cleared the neighborhood

A planet has "___________ _____ ________________" of smaller objects

Gravity

A planet is large enough for its own __________ to make it round

Kepler-90

Multi-planet system that has the most (8) confirmed exoplanets, which implies that there are many more planets than stars in the Galaxy

They migrate inward (toward their star)

Why are the first extrasolar planets so close to their star?

The first extrasolar planets

1. Masses larger than Jupiter.
2. Eccentric orbits.
3. Are located very close to their stars (closer than the Earth).

Transit

Most extrasolar planets have been found using what method?

Wobble

Increasing the mass of a planet and/or moving it closer to its star can make it ___________ more

Transit Method

- Planet orbits in front of star, and the amount of light from the star decreases a little.
- Orientation along line of sight.
- Yields size of star.
- Difficult to measure.
Main idea: A method for detecting extrasolar planets that come between us and their parent star, dimming the star's light.

Blueshift

Shift of light to a shorter wavelength as it moves closer

Redshift

Shift of light to a longer wavelength as it moves away

Radial Velocity Method

- Also called the Doppler shift method.
- Spectrum shifts blue-red, red-blue (star wobbling toward or away from us).
- Orbit must be flat to us (the viewer).
- Yields planet's orbital period, mass (sum of masses), and distance from star.
Main idea: A technique used to detect extrasolar planets by observing Doppler shifts in the spectrum of the planet's star.

Astrometric Method

A technique for detecting extrasolar planets by looking for stars that wobble periodically (through a series of photos due to it being detected from precise measurements)

3 Methods for Detecting Planets Around Stars

1. Astrometric method,
2. Radial velocity method,
3. Transit method

Extrasolar planet

A planet beyond our solar system, orbiting a star other than our Sun

Conservation of Angular Momentum

How do we explain the orbits of planets being in the same plane and orbiting in the same direction?

Gravity

How did the solar nebula heat up?

Yes

Are meteorites all nearly the same age?

4.56 billion years old

How old is the solar system?

Half-Life

The time required for one-half of a quantity of a radioactive substance (the nuclei) to decay

Radioactive Decay

The process whereby certain atomic nuclei spontaneously transform into other nuclei; Change from one element to another

Radioactive Dating

A technique for determining the age of a rock sample by measuring the radioactive elements and their decay products in the sample

Core Accretion Model

The hypothesis that each of the Jovian planets formed by accretion of gas onto a rocky core

Jovian Planet Formation

Collide and stick (gas accretion) + ice

Differentiation

The process by which the heavier elements (denser objects) in a planet sink toward its center while lighter elements (less dense objects) rise towards its surface

Accretion

the coming together and cohesion of matter under the influence of gravitation to form larger bodies; collide and stick

Terrestrial Planet Formation

1. Dust grains and pebbles collide sticking together.
2. They accumulate into larger planetesimals.
3. Planetesimals collide and stick, forming protoplanets.
4. Protoplanets collide and stick, forming planets.

The Sun's heat (radiation)

What pushed away gas in the inner region of the solar nebula, leaving the other materials (rocky materials and gases) to form rocky planets near our Sun and gaseous planets further away in the outer parts of the solar system?

Warmer, cooler

As the protosun was growing, the inner parts of the solar nebula were _______ while the outer parts were ________ (temp).

Protoplanetary Disk

A disk of material encircling a protostar or a newborn star, formed from a flattened nebula (caused by contraction and rotation). Planets orbit in the same direction on the same plane due to the:

Conservation of Angular Momentum

The angular momentum of an object cannot change unless an external twisting force (torque) is acting on it.
L = (m)(Vrot)(r) [L - angular momentum, m - mass, Vrot - rotational velocity, r - radius]

(When there is) Fusion in the core

When does a star actually become a star?

Proto-

Before, first

Gravity (took it there)

Why is the Sun at the middle of the solar system?

Jupiter-like

What were the first exoplanets like?

Kepler Mission

determined how many earth-sized planets there are in or near the habitable zone using transit method (also the reason why the transit method has the most planet detections)

Exoplanet properties

Jupiters (Jupiter-like), Neptunes (in size), Super-earths (a little more massive than Earth), Earths

700+

____ (number) super-earths confirmed, with many more candidates

Crust

Part of the Earth's interior that has low density, mainly silicates; made out of lighter material from the process of differentiation

Mantle

Part of the Earth's interior that is mainly iron-magnesium; slow motion, like wax

Core

Part of the Earth's interior that contains two different types: Outer, which is a dense liquid material that is made of a mixture of iron, nickel, and perhaps sulfur AND Inner, which is solid and consists of iron and nickel

Seismic waves

elastic waves in the earth produced by an earthquake or other means

P waves

longitudinal seismic waves

S waves

transverse seismic waves that cannot travel through liquid, meaning that they cannot travel through the outer core

Quicker

Smaller bodies radiate heat ____________ (rate)

Hotter

Larger bodies should have ____________ (temperature) interiors

Longer

The Earth holds a lot of heat, meaning that it takes ____________ (rate) to cool down

No

Do Earth's geometric poles and magnetic poles line up?

Planet-wide magnetic field

A planet has a ____________-_____ ____________ _________ if:
1. It has charged material.
2. The charged material is put in motion (it most be put in motion).

Static (fixed)

Magnetic fields are not __________. North and south poles move independently.

Flips

Our magnetic field does this from time to time; no one knows why this occurs, but another one will be occurring soon

Solar wind

Charged particles (mostly protons and electrons) emitted by the Sun; steady/constant

Aurora

an atmospheric phenomenon consisting of bands of light caused by charged solar particles from the magnetosphere striking atoms in the upper atmosphere, which causes the gases to emit light

Hot

A planet or moon with this type of interior (temperature) is needed to shift the crust (plate tectonics)

Plate tectonics

Evidence of _______ ______________:
1. Does the planet/moon have mountain ranges?
2. Does it have riffs?
3. Subduction? (One crust may slip beneath another, melt the old crust, and mixes it in with the new crust)
4. Earthquakes?

New crust

At a riff between separating plates, lava oozes upward and forms:

Mountain ranges

Where plates collide, deep oceanic trenches and ______________ ________ are formed

Nitrogen

What element is Earth's atmosphere mostly made of (78%)?

Coriolis Effect

When Earth rotates, it causes the path of an object to change; less rotation = less of this effect, and more rotation = more of this effect

Greenhouse effect

the trapping of the sun's warmth in a planet's lower atmosphere due to the greater transparency of the atmosphere to visible radiation from the sun than to infrared radiation emitted from the planet's surface

Greenhouse gases

CO2 and H20 (water vapor)

No (too small)

Does the Moon have an atmosphere?

Maria

Dark, flat areas on the moon's surface formed from huge ancient lava flows; lack of craters = younger surface

More dense

Is the material in Maria more or less dense than the material in the Lunar Highlands?

Lunar Highlands

Older, light-colored terrain, heavily cratered portions of the Moon's surface; Predominately on the far side of the moon where the crust is thicker

Less, older

The Highlands tend to be [less or more?] dense and [older or younger?]

One

The Moon is a ______ plate world, due to its crust cooling down fast, creating a thick crust with no plate tectonics

No (its too cooled down)

Does the Moon have a magnetic field?

Yes

Do quakes happen on the moon?

Crust

Part of the Moon's structure that varies in thickness

Mantle

Part of the Moon's structure that is too cold and rigid

Small molten core

Part of the Moon's structure that contains a lower percentage of iron than Earth