Thursday, February 28, 2013

Allison Thompson Quiz 6

1. What does the solar system look like?
* Tiny planets with clear patterns and motions.
* Planets are tiny compared to the distance between them.
 
2.What features of our solar system provide clues to how it formed?
 * Sun, planets, and moons orbit in an organized way.
* Terresetrial Planets are rocky, small and close to the sun.
*Jovial Planets are large, gasous and far from the sun.

3. What theory best explains the features of our solar system?
Nebular

4. Where did the solar system come from?
 The cloud of gas that gives birth to our solar system resulted in from the recycled of gas through many generation of stars within our galaxy.


5.What caused the orderly patterns of motion in our solar system?
 As gravity forced the cloud to become smaller, it begun to spin faster.
*As gravity forced the cloud to shrink, it spins faster.
* Collisions forced the cloud to compress into a disc.
* Collisions between gas particles gradually reduce random motions
* Collisions between gas particles all reduce up and down motions
* Spinning cloud flattens as it shrinks


6. Why are there two major types of planets?
 Outer planet gets bigger because of the abundance of hydrogen compounds
* Outer planets accrete and keep H/He gases

7.  Where did asteroids and comets come from?
Left over planetesimals pieces

8. How do we explain the existence of our Moon and other exceptions to the rules?
A big planetesimal slammed into a newly formed earth. Rotations are the only exceptions.

9.  When did the planets form?
We are not sure.

10.How do we detect planets around other stars?

Allison Thompson Chapter 6 Notes

What does the Solar System look like?
* Tiny planets with clear patterns and motions.
* Planets are tiny compared to the distance between them.

The Sun:
* Over 99.9% of the Solar System's mass
*Mostly H/HE
*Converts over 4 million tons of mass into energy

Mercury:
* Made of metal and rock
* Desolated craters with long, tall, steep cliffs
* Very hot and very cold.

Venus
* Nearly Earth's size
* Hellish conditions
* Hotter than Mercury
* Atmospheric pressure as deep as 1km in the ocean
* No oxygen/ no water

Earth
* Oasis of life
* Only planet with liquid
* Surprisingly large moon

Mars
* Looks like Earth
* Giant Volcanoes, huge canyons, and polar caps.

Jupiter
* Farther from the sun
* Different compositions no solid surface
* Giant for a planet
* Many moons

Saturns
* Giant and gases like Jupiter 
* Most spectural rings of the 4 Jovial Planets
* Many moons
* Currently under observation
* Rings are not solid, made of countless rocks and ice chunks orbiting like a moon.

Uranus
* Much smaller than Jupiter/ Saturn but larger than earth
* Extreme axis tilt
* Moons also tip in their orbit

Neptune
* Very similar to Uranus
* Many moons are unusual. Triton orbits backwards

Pluto
* Misfit among planets
* Comet like positions
*Moon is half size of Pluto

What features our Solar System provide clues to how it formed?
* Sun, planets, and moons orbit in an organized way.
* Terresetrial Planets are rocky, small and close to the sun.
*Jovial Planets are large, gasous and far from the sun.

What theory best explains the features of our solar system?
* Nebular Theory

Where did the solar system come from?
* The cloud of gas that gives birth to our solar system resulted in from the recycled of gas through many generation of stars within our galaxy.

What caused the orderly pattern of motions in our solar system?
* As gravity forced the cloud to become smaller, it begun to spin faster.
*As gravity forced the cloud to shrink, it spins faster.
* Collisions forced the cloud to compress into a disc.
* Collisions between gas particles gradually reduce random motions
* Collisions between gas particles all reduce up and down motions
* Spinning cloud flattens as it shrinks

Why are there two types of planets, when all planets are formed from the same nebula?
* As gravity causes clouds to contract, it heats up .
* Inner disks are hotter than outer parts
* Rocks can be much more solid at higher temperatures than ice. 
* Inner frost line is to hot for hydrogen compounds to form ice
* Outer frost line is cold enough to form ice
* Tiny solid particles stick together
* Gravity draws planetesimals to form planets. Process is called accretion
* Gravity of rocks and ice in jovial planets draws in H and HE
* Moons of jovial planets form in miniature disks

Why are there two types of planets?
* Outer planet gets bigger because of the abundance of hydrogen compounds
* Outer planets accrete and keep H/He gases

When did the planets form?
* We cannot find the age of planets.

How do we detect planets around other stars?
* By looking for periodic motion as the stars orbit.

What have other planet systems taught us about our own?
* Planetary systems exhibit a surprising range of layouts, suggesting  that jovial planets sometimes migrate inward from where they were born. It shows that the nebular theory is incomplete.


Chapter 6 Quiz: Olivia Ward


  1. What does the solar system look like?

    Our solar system is made up of planets and their moons, asteroids, and comets that orbit the sun. The planets are little compared to the distance between them. Every planet has its own characteristics, but there are definite patterns that occur throughout. The planets include Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Pluto is considered a dwarf planet.

  2. What features of our solar system provide clues to how it formed?

    There are four major clues that give us clues about the solar system's formation. The sun, planets, and large moons generally rotate and orbit in very organized ways. The planets can be divided into two groups: terrestrial and jovian. The solar system contains a large amount of asteroids and comets, some even being large enough to be considered dwarf planets. Last, but  not least, there are some notable exceptions to these patterns.
  3.  What theory best explains the features of our solar system?
    The Nebular Theory best explains our solar system. A rotating nebula contracted which caused the cloud to heat, flatten, and spin faster. This resulting in a spinning disk of dust and gas. The gas, H and He, remained gaseous, but the other material further condensed into "seeds" for building planets. These "seeds" collided and merged together. The larger merged formed attracted smaller ones. The nebula was then cleared by solar winds which blew the remaining gas into interstellar space.


  4. Where did the solar system come from?

    The solar system came from a cloud of gas. This cloud was produced through galactic recycling through many generations of stars. The gas consisted of 98% H and He, and 2% of all of the other elements.
  5. What caused the orderly patterns of motion in our solar system?

    Our solar system started out as a spinning disk of gas and dust, a collapsing gas cloud. The orderly motions that we see cam from the orderly motions of that spinning disk.
  6. Why are there two major types of planets?

    In the inner solar system, the high temperatures caused terrestrial planets to form. Only metal and rock could condense, which explains composition of terrestrial planets. Because of the cool temperatures of the outer solar system, only jovian planets could form. The temperatures allowed ices to condense, as well as metal and rock.

  7. Where did asteroids and comets come from?

    Asteroids are the rock leftovers that planetesimals of the inner solar system. Comets are the icy leftovers of planetesimals of the outer solar system. Asteroids are believed to be pieces of a broken planet while comets are chunks of rock, dust, ice, and frozen gases.

  8. How do we explain the existence of our Moon and other exceptions to the rules?

    Most of the exceptions to these rules likely cam from collisions or close encounters with leftover planetesimals. Our Moon is most likely the result of a giant impact between a Mars-size planetesimal and Earth.

  9. When did the planets form?

    The planets formed 4.6 billion years ago. This was determined by radiometric dating of the oldest meteorites.

  10.  How do we detect planets around other stars?

    We are able to detect extrasolar planets by indirectly observing the planet's effects on the star it orbits. Most discoveries have been made by using the Doppler technique. Doppler shifts reveal the gravitational tug of a planet on a star.

Chapter 6 Quiz: Jessica Horn


Quiz


  1. What does the solar system look like? The planets are tiny compared to the distances between them. Our solar system consists of the Sun, the planets and their moons, and vast numbers of asteroids and comets. Each world has its own unique character, but there are many clear patterns among the worlds.
  2. What features of our solar system provide clues to how it formed? Four major features proved clues. 1. The Sun, planets, and large moons generally rotate and orbit in a very organized way. 2. The planets divide clearly into two groups: terrestrial and Jovian  3. The solar system contains vast numbers of asteroids and comets, some large enough to qualify as dwarf planets. 4. There are some notable exceptions to these general patterns, 
  3.  What theory best explains the features of our solar system? The nebular theory, which holds that the solar system formed from the gravitational collapse of a great cloud of gas and dust, successfully explains all the major features of our solar system.
  4. Where did the solar system come from? The cloud of gas that gave birth to our solar system was the product of recycling of gas through many generations of stars within our galaxy. This gas consisted of 98% hydrogen and helium and 2% all other elements. 
  5. What caused the orderly patterns of motion in our solar system? A collapsing gas cloud tends to heat up, spin faster, and flatten out as it shrinks in size  Our solar system began as a spinning disk of gas and dust, so the orderly motions we observe today came from the orderly motion of this spinning disk.
  6. Why are there two major types of planets? Planets formed around solid "seeds" that condensed from gas and then grew through accretion. In the inner solar system, temperatures were so high that only metal and rock could condense, which explains why terrestrial worlds are made of metal and rock. In the outer solar system, cold temperatures allowed more abundant ices to condense along with metal and rock. Icy planetesimals grew large enough for their gravity to draw in hydrogen and helium gas, forming the massive Jovian planets.
  7. Where did asteroids and comets come from? Asteroids are the rocky leftover planetesimals of the inner solar system, and comets are the icy leftover polanetesimals of the outer solar system.
  8. How do we explain the existence of our Moon and other exceptions to the rules? Most of the exceptions probably arose from collisions or close encounters with leftover planetesimals. Our Moon is most likely the result of a giant impact between a Mars-size planetesimal and the young Earth.
  9. When did the planets form? The planets began to accrete in the solar nebula about 4.55 billion years ago.
  10.  How do we detect planets around other stars? So far, we are best able to detect extra-solar planets indirectly by observing the planet's effects on the star it orbits. Most discoveries to date have been made with the Doppler technique, in which Doppler shifts reveal the gravitational tug of a planet on a star. We can also search for transits and eclipses in which a system becomes slightly dimmer as a planet passes in frot of or behind its star. 

Chapter 6 Notes: Jessica Horn

Chapter 6: Formation of Planetary Systems. Our Solar System and Beyond

  • The solar system exhibits clear patterns of composition and motion.
  • These patterns are far more important and interesting than numbers, names, and other trivia.
  • Planets are very tiny compared to distances between them.
    • Sun
      • Over 99.9% of solar system's mass
      • Made mostly of H/He gas (plasma)
      • Converts 4 million tons of mass into energy each second
    • Mercury
      • Made of metal and rock; large iron core.
      • Desolate, cratered; long, tall, steep cliffs.
      • Very hot and very cold: 425 degrees Celsius (day), -170 degrees Celsius (night). 
    • Venus
      • Nearly identical in size to Earth; surface hidden by clouds.
      • Hellish conditions due to an extreme greenhouse effect.
      • Even hotter than Mercury; 470 degrees Celsius, day and night.
    • Earth
      • An oasis of life.
      • The only surface liquid water in the solar system.
      • A surprisingly large moon.
    • Mars
      • Looks almost Earth-like.
      • Giant volcanoes, a huge canyon, polar caps, and more.
      • Water flowed in the distant past.
    • Jupiter
      • Much farther from Sun than inner planets.
      • Mostly H/He; no solid surface.
      • 300 times more massive than Earth.
      • Many moons, rings.
    • Saturn
      • Giant and gaseous like Jupiter.
      • Spectacular rings.
      • Many moons, including cloudy Titan.
      • Cassini spacecraft currently studying it.
    • Uranus
      • Smaller than Jupiter/Saturn; much larger than Earth.
      • Made of H/He gas and hydrogen compounds.
      • Extreme axis tilt.
      • Moons and rings.
    • Neptune
      • Similar to Uranus, except for axis tilt.
      • Many moons, including Triton.
    • Pluto and Eris (Dwarf Planets)
      • Much smaller than other planets.
      • Icy, comet-like composition.
      • Pluto's moon Charon is similar to Pluto.
    • Motion of Large Bodies
      • All large bodies in the solar system orbit in the same direction in nearly the same plane.
      • Most also rotate in that direction.
    • Two Major Planets
      • Terrestrial planets are rocky, relatively small, and close to the Sun.
      • Jovian planets are gaseous, larger, and farther from the Sun.
    • Swarms of Smaller Bodies
      • Many rocky asteroids and icy comets populate the solar system.
    • According to Nebular Theory, our solar system formed from a giant cloud of interstellar gas.
    • Galactic Recycling
      • Elements that formed planets were made in stars and then recycled through interstellar space.
    • Conservation of Angular Momentum: The rotation speed of the cloud from which our solar system formed must have increased as the cloud contracted.
    • Conservation of Energy: As gravity causes the cloud to contract, it heats up.
    • Inside the frost line: Too hot for hydrogen compounds to form ices.
    • Outside the frost line: Cold enough for ices to form.
  • Formation of Terrestrial Planets
    • Small particles of rock and metal were present inside the frost line.
    • Planetesimals of rock and metal built up as these particles collided. 
    • Gravity eventually assembled these planetesimals into terrestrial planets.
  • Formation of Jovian Planets
    • Ice could also form small particles outside the frost line.
    • Larger planetesimals and planets were able to form.
    • The gravity of these larger planets was able to draw in surrounding H and He gases. 
  • Asteroids and Comets
    • Leftovers from the accretion process.
    • Rocky asteroids inside the frost line.
    • Icy comets outside frost line.
  • Captured Moons
    • The unusual moons of some planets may be captured planetesimals. 
  • Odd Rotation
    • Giant impacts might also explain the different rotation axes of some planets.
  • Dating the Solar System
    • Age dating of meteorites that are unchanged since they condensed and accreted tells us that the solar system is about 4.6 billion years old. 

Chapter 6 Notes: Olivia Ward

Formation of Planetary Systems: Our Solar System and Beyond

6.1 A Brief Tour of the Solar System
What does the solar system look like?
  • The solar system exhibits clear patters of composition and motion.
  • Large bodies in the solar system have orderly motion. All planets have circular orbits going in the same direction and nearly in the same plane.
  • Planets fall into two major categories: small & rocky terrestrial planets and large, hydrogen-rich jovian planets
  • Swarms of asteroids and comets populate the solar system. Vast numbers of rocky asteroids and icy comets are found throughout the solar system.
  • Several notable exceptions to these trends stand out: some planets have unusual axis tilts.
  • The Solar System
    • The Sun
      • Over 99.8% of the solar system's mass
      • Made mostly of H and He gas (plasma)
      • Converts 4 million tons of mass into energy each second
    • Mercury
      • Made of metal and rock: large iron core
      • Desolate, cratered, long & tall steep cliffs
      • 425° C during the day, -170° C during the night
    • Venus
      • Nearly identical to the size of Earth
      • Surface hidden by clouds
      • Hellish conditions due to an extreme greenhouse effect
      • Even hotter than Mercury: 470°C day and night
    • Earth
      • An oasis of life
      • The only surface of liquid water in the solar system
      • A surprisingly large moon
    • Mars
      • Looks almost like Earth
      • Giant volcanoes, a large canyon, polar caps
      • Water flowed in the distant past
    • Jupiter
      • Much farther from the Sun than the other inner planets
      • Mostly H & He, no solid surface
      • 300 times more massive than Earth
      • Many moons:
        • Io (active volcanoes all over)
        • Europa (possible subsurface ocean)
        • Ganymede (largest moon in the solar system)
        • Callisto (a large, cratered ice ball)
    • Saturn
      • Giant and gaseous like Jupiter
      • Spectacular rings
      • Many moons (including Titan)
      • Rings are not solid. They are made out of chunks of ice and rock.
    • Uranus
      • Smaller than Jupiter & Saturn, much larger than Earth
      • Made of H & He gas and hydrogen compounds
      • Extreme axis tilt
      • Moons and rings
    • Neptune
      • Similar to Uranus (except axis tilt)
      • Many moons (Triton)
    • Pluto
      • Much smaller than other planets (dwarf planet)
      • Icy, comet-like composition

6.2 Clues tot he Formation of our Solar System
What features of our solar system provide clues to how it formed?
  • Two major planet types: terrestrial and jovian
  • Swarms of smaller bodies
    • Many rock asteroids and icy comets populate the solar system
  • Notable exceptions
    • Rotation of Uranus
    • Earth's large moon
What theory best explains the features of our solar system?
  • Nebular Theory: our solar system formed from a giant cloud of interstellar gas (nebula = cloud)


6.3 The Birth of the Solar System
Where did the solar system come from?
  • Galactic Recycling
    • Elements that formed planets were made in stars and then recycled through interstellar space (process repeats).
  • Evidence from other gas clouds
    • We can see stars forming in other interstellar gas. (clouds lending support in the nebular theory)
What caused the orderly patterns of motion in our solar system?
  • Conservation of angular momentum
    • The rotation speed of the cloud from which our solar system formed must have increased as the cloud contracted.
  • Flattening
    • Collisions between gas particles in the cloud
    • The spinning cloud flattens
  • Disks around other stars
    • Observations of disks around other stars support the nebular hypothesis


6.4 Learning from Light
Why are there two major types of planets?
  • Planets fall into two major categories:
    • Small: rocky terrestrial planets
    •  Large: hydrogen-rich jovian planet
  •  Formation of terrestrial planets
    • Small particles of rock and metal were present inside the frost line.
    • Planetesimals of sock and metal built up as these particles collided.
    • Gravity eventually assembled these planetesimals into terrestrial planets.
  • Accretion of Planetesimals
    • Many smaller objects collect into just a few large ones.
  • Formation of jovial planets
    • Ice could also form small particles outside the frost line.
    • Larger planetesimals and planets were able to form.
  •  Asteroids and Comets
    • Leftovers from the accretion process
    • Rocky asteroids inside frost line
    • Icy comets outside frost line
  • Heavy Bombardment
    • Leftover planetesimals bombarded other objects in the late stages of solar system foundation.
  • Origin of Earth's Water
    • Water may have come to Earth by way of icy planetesimals from the outer solar system.
How do we explain the existence of our Moon and other exceptions to the rules?
  • Captured Moons
    • The unusual moons of some planets may be captured planetesimals (irregular shaped).
  • Odd Rotation
    • Giant impacts might also explain the different rotation axes of some planets
When did planets form?
  • 4.6 billion years ago
  • Radioactive Decay
    • Some isotopes decay into other nuclei
      A half life is the time for half the nuclei in a substance to decay.

U.S. Cities on Front Line as Sea Levels Rise: Scientific American

U.S. Cities on Front Line as Sea Levels Rise: Scientific American:

"The signs of rising water are everywhere in this seaport city: yellow "Streets May Flood" notices are common at highway underpasses, in low-lying neighborhoods and along the sprawling waterfront."

'via Blog this'

Psychological Challenges of a Manned Mission to Mars

Psychological Challenges of a Manned Mission to Mars:

 "We all have them—a sibling who "borrows" your clothes without returning them, a co-worker who never puts your stapler back where she found it, a spouse who refuses to pick up his socks."

'via Blog this'

Monster Black Hole's Spin Revealed for 1st Time: Scientific American

Monster Black Hole's Spin Revealed for 1st Time: Scientific American:

 "Astronomers have made the first reliable measurement of a supermassive black hole's spin, showcasing a technique that could help unravel the mysteries of these monsters' growth and evolution."

'via Blog this'

Paricutín: “Save Me From the Dangers in Which I am About to Die” | Rosetta Stones, Scientific American Blog Network

Paricutín: “Save Me From the Dangers in Which I am About to Die” | Rosetta Stones, Scientific American Blog Network:

"Dionisio Pulido suddenly found himself having a very bad day."

'via Blog this'

Wednesday, February 27, 2013

Chelsea Esposito Notes


Chapter 1

Our place in the Universe

Star – a large, glowing, ball of gas that generates heat and light through nuclear fusion.

Planet- A moderately large object that orbits a star. It shines by reflecting light. Planets may be rocky,
icy, or gaseous.

Moon (or satellite) - An object that orbits a planet

Asteroid- A relatively small and rocky object that orbits a star.

Comet- A small and icy object that orbits a star

Nebula- an interstellar cloud of gas and/or dust

Galaxy- a great island of starts in space, all held together by gravity and orbiting a common center.

-Andromeda is our closest galaxy

How did we come to be?

Birth of universe: the expansion of the universe began with a hot and dense Big Bang. One region of
the universe has expanded with time. The universe continues to grow but, on a smaller scale gravity
has pulled matter together to make galaxies.

Galaxies as Cosmic Recycling Planets: The early universe contained only two chemical elements:
hydrogen and helium. All other elements were made by starts and recycled from one stellar
generation to the next with in galaxies like our Milky Way.

Life Cycles of Stars: Many generations of starts have lived and died in the MW.

Earth and Life: By the time our SS was born, 4.5 billion years ago, about @5 of the original hydrogen
and He had been converted into heavier matter.

How can we know what the universe was like in the past?

Light travels at a finite speed: 300,000 km/s

Thus, we see objects as they were in the past. The farther away we look in distance, the further back
we look in time.

Light year- the distance light can travel in one year, about 10 trillion km (6 trillion miles). At great
distances, we see objects as they were when the universe was much younger.

Can we see the entire universe?

No. There may be things from farther away and the light has no reached us.

How big is the universe?

The MW is about 100 billion galaxies. 10^11 stars/galaxy x 10^11 galaxies = 10^22

It has as many stars as grains of sand on the of Earth’s beaches.

How is the Earth moving?

Contrary to our perception, we are not “sitting still”. We are moving with the Earth. Earth rotates
around its axis once every day. At typical relative speeds of more than 70,000 km/hr. Starts are so far
away that we cannot easily notice their motion.

Do galaxies move?

Galaxies are carried along with the expansion of the universe. How did Hubble figure it out?

Are we ever sitting still?

No. Everything is always expanding, rotating, or growing.

CHAPTER 2

The Celestial Sphere

Starts at different distances all appear to lie on the celestial sphere. The ecliptic is the Sun’s apparent
path. The 88 official constellations cover the celestial sphere.

The Milky Way

A band light that makes a circle around the celestial sphere. What is it? Our view into the galaxy.

An objects altitude (above horizon) and direction (along horizon) specify its location in our local sky.

Zenith- the point directly overhead

Horizon- all points 90 degrees away from the Zenith

CHAPTER 4

Making Sense of the Universe: Understanding Motion

Energy and Gravity

How do we describe motion?
How is mass different from weight?

1.
2.

Speed: Rate at which objects move

Speed = distance/time (units of m/s)

Velocity: speed and direction

Acceleration: Any change in velocity. Units of speed/time (m/s^2)

Acceleration of Gravity

All falling objects accelerate at the same rate (not counting friction of our resistance.)

On Earth g ≈ 10 m/s^2 : speed increases 10 m/s, with each second of falling

Acceleration of Gravity (g)

Galileo showed that g is the same for all falling objects, regardless of their mass.
Momentum = m x V
A net force changes momentum which generally means an acceleration ( Δ in velocity)
The rotational momentum of a spinning or orbiting object is known as angular momentum

-
-
-
-

Mass – amount of matter in an object

Weight- the force that acts on an object

On the moon, your weight is less, your mass is the same

Why are astronauts weightless in space?

-There is gravity in space

-weightlessness is due to a constant state of free-fall

Mass= quantity of matter

Weight= force acting on mass

4.2 Newton’s Laws of Motion

How did Newton change our view of the universe?

What are Newton’s three laws of motion?

How did Newton change our views of the Universe? Newton 1642-1727

- He realized the same physical laws that operate on Earth also operate in the heavens -> one
universe

- Discovered laws of motion and gravity

- Much more: experiments with light, first reflecting telescope, calculus.

Newton’s Three Laws

1st: an object moves at constant velocity unless an Earth force acts to change its speed or direction.

2nd: force = mass x acceleration

3rd: For every force, there is always an equal and opposite reaction force.

Is the force that Earth exerts on you longer, smaller, or the same as the force you exert on it?

Earth and you exert equal and opposite forces on each other.

4.3 Conversation Laws in Astronomy

- What keeps a planet rotating and orbiting the sun?

- Where do objects get their energy?

Conservation of Momentum?

The total momentum of interacting objects cannot change unless an external force is acting
on them.
Interacting objects exchange momentum through equal and opposite forces.

-

-

What keeps a planet rotating and orbiting the sun?

Angular Momentum

Am = mass x acceleration

Where do objects get their energy?

-
-

Energy makes matter move.
Energy is conserved, but it can…
o Transfer from one object to another
o Change in form.

Basic types of energy
- Kinetic (motion)
- Radiation (light)
- Stored or potential

Energy can change type but cannot be destroyed.

Thermal Energy: The collective kinetic energy of many particles.
- Thermal energy is related to temperature but it is not the same.
- Measure of the total kinetic energy of all the particles in a substance. It, therefore, depends
on both temperature AND density.

Gravitational Potential Energy

-
-
-
-

on Earth , it depends on…
an objects mass (m)
strength of gravity (g)
-distance an object could potentially fall.

The Force of Gravity

-Universal Law of Gravitation

1. Every mass attracts every other mass

2. Attraction is directly proportional to the product of their mass.

How does Newton’s law of gravity extend Kepler’s Laws?

Kepler’s finest two laws apply to all orbiting objects, not just planets.
Ellipses are not the only orbital paths.

-
-

Newton’s version of Kepler’s 3rd law: If a small object orbits a larger one and you measure the
orbiting object’s orbital period AND average orbital distance.

How do energy and gravity together allow us to understand orbits?

-
-

Total orbital energy (grav. + kinetic energy) stays constant if there is no external force.
Orbits cannot change spontaneously.

Changing an Orbit

è What can make an object gain or lose orbital en?
o Friction or atmospheric drag
o A gravitational encounter

Escape Velocity
- If an object gains enough orbital energy, it may escape (change from a bound to unbound
orbit).
- Escape velocity from Earth

Tide s

The moon’s gravity pulls harder on near side of Earth than on far side.
The difference in the moon’s grav. Pull stretches the Earth.
Size of the tide depends on the phase of the moon.

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-
-

Tidal Friction

-Tidal friction gradually slows Earth’s rotation (and makes the moon get father from Earth).

- Moon once orbited faster (or slower), t.f. caused it to “lock” in synchronous rotation.

CHAPTER 6

-closer to the sun, the faster the orbit

- Planetecimal - little pieces of a planet

Breif Tour

The solar system exhibits clear patterns of composition and motion.

These patterns are far more important and interesting than numbers, names, and other trvia.

Planets fall into two categories

small, rocky terrestrial planets
large, hydrogen-rich jovian planets

-
-

Asteroids and comets populate the solar system

found throughout, but are concentrated in 3 distinct regions.

-

Several notable exceptions to these trends stand out.

some planets have unusual axis tilts, unusually large moons, or moons of unusual orbits
Planets are very tiny compared to the distances between them.

-
-

SUN

-
-
-

Over 99.8% of solar system’s mass
Made mostly of gas (H/He) (plasma)
Converts 4 million tons of mass into energy each second.

Mercury

- Made of metal and rock; large iron core

- Desolate, cratered; long, tall, steep cliffs.

- Very hot and very cold, day 475 degrees Celsius, night -170 degreeds Celsius

Venus

Nearly identical in size to Earth; surface hidden by clouds
Hellish conditions due to an extreme green-house effect
Even hotter than Mercury: 470C, day and night

-
-
-

Earth

-
-
-

an oasis of life
only surface with liquid water in the ss
a surprisingly large moon

Mars

Looks almost Earth-like
Giant volcanoes, a huge canyon, polar caps, and more
Water flowed in the distant past; could there have been life?

-
-
-

Jupiter

much farther from the sun than inner planets
4 moons
o Io: active volcanoes
o Europa: possible subsurface ocean
o Ganymede
o Callisto

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Saturn

Giant and gaseous like Jupiter
Spectacular rings
Many moons
Its rings are not solid
Cassini launched ’97, landed in ‘04

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Uranus

Smaller than Jupiter and Saturn
Made of H/He

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Neptune

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Axis tilt

Pluto & other Dwarves

To small to clear an orbital path to be considered a planet.

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6.2 Clues to the Formation of Our Solar System

What features of our solar system provide clues to how it formed?

Motion of large bodies
o All in same direction & plane

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Swarms of small bodies

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Many rocky asteroids and icy comets populate the solar system
Oort Cloud, Kuiper belt, asteroid belt

Notable Expectations

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unusual axis tilts

Nebular Theory

Unusual axis tilts

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Nebular Theory

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Our ss formed from a giant cloud of interstellar gas.
(nebular = cloud_

6.3 Birth of SS

Galactic Recycling

Elements that formed planets were made in starts and then recucled through interstellar
space.
We can see stars forming in interstellar gas clouds.

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Conservation of Angular Momentum

Heating, Spinning faster, Flattening

-like a ballerina bringing in her arms during a spin

Formation of Terrestrial Planets

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small particles of rock and metal were present inside the frost line.
Planetesimals of rock and metal built up as these particles collided.
Gravity eventually assembled these planetesimals into terrestrial planets.

Tiny solid particles stick to create planetesimals.

Accretion of Planetesimals

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Many smaller objects collected into just a few larges ones.

Formation of Jovian Planets

Ice could form small particles outside the frost line.
Larger planetesimals.-

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Tuesday, February 26, 2013

Chapter 6 Quiz Jessica Brandon


Chapter 6 Quiz
1.     What does the solar system look like?
·      Planets are tiny compared to the distances between them.
·      Each world has its own character, but there are many clear patterns.

2.     What features of our solar system provide clues to how it formed?
·      Motions of large bodies:  All in same direction and plane
·      Two major planet types: Terrestrial and jovian
·      —Swarms of small bodies: Asteroids and comets
·      Notable exceptions: Rotation of Uranus, Earth’s large moon, and so forth

3.     What theory best explains the features of our solar system?
·      The nebular theory, which holds that our solar system formed from a cloud of interstellar gas, explains the general features of our solar system.

4.     Where did the solar system come from?
·      Galactic recycling built the elements from which planets formed.
·      We can observe stars forming in other gas clouds.

5.     What caused the orderly patterns of motion in our solar system?
·      The solar nebula spun faster as it contracted because of conservation of angular momentum.
·      Collisions between gas particles then caused the nebula to flatten into a disk.
·      We have observed such disks around newly forming stars.

6.     Why are there two major types of planets?
·      Rock, metals, and ices condensed outside the frost line, but only rock and metals condensed inside the frost line.
·      Small solid particles collected into planetesimals that then accreted into planets.
·      Planets inside the frost line were made of rock and metals.
·      Additional ice particles outside the frost line made planets there more massive, and the gravity of these massive planets drew in H and He gases.

7.     Where did asteroids and comets come from?
·      They are leftover planetesimals, according to the nebular theory.

8.     How do we explain the existence of our Moon and other exceptions to the rules?
·      The bombardment of newly formed planets by planetesimals may explain the exceptions.
·      Material torn from Earth’s crust by a giant impact formed the Moon.

9.     When did the planets form?
·      Radiometric dating indicates that planets formed 4.5 billion years ago.

10. How do we detect planets around other stars?
·      A star’s periodic motion (detected through Doppler shifts) tells us about its planets.
·      Transiting planets periodically reduce a star’s brightness.
·      Direct detection is possible if we can block the star’s bright light.

Chapter 6 Notes Jessica Brandon



Chapter 6 Formation of Planetary Systems Our Solar System and Beyond
·      The solar system exhibits clear patterns of composition and motion.
·      These patterns are far more important and interesting than numbers, names, and other trivia.
·      Planets are very tiny compared to distances between them.
Sun
·      Over 99.9% of solar system’s mass
·      Made mostly of H/He gas (plasma)
·      Converts 4 million tons of mass into energy each second
Mercury
·      Made of metal and rock; large iron core
·      Desolate, cratered; long, tall, steep cliffs
·      Very hot and very cold: 425°C (day), –170°C (night)
Venus
·      Nearly identical in size to Earth; surface hidden by clouds
·      Hellish conditions due to an extreme greenhouse effect
·      Even hotter than Mercury: 470°C, day and night
Earth
·      An oasis of life
·      The only surface liquid water in the solar system
·      A surprisingly large moon
Mars
·      Looks almost Earth-like, but don’t go without a spacesuit!
·      Giant volcanoes, a huge canyon, polar caps, and more
·      Water flowed in the distant past; could there have been life?
Jupiter
·      Much farther from Sun than inner planets
·      Mostly H/He; no solid surface
·      300 times more massive than Earth
·      Many moons, rings Jupiter Jupiter’s moons can be as interesting as planets themselves, especially Jupiter’s four Galilean moons
·      Io (shown here): Active volcanoes all over
·      Europa: Possible subsurface ocean
·      Ganymede: Largest moon in solar system
·      Callisto: A large, cratered “ice ball”Saturn
·      Giant and gaseous like Jupiter
·      Spectacular rings
·      Many moons, including cloudy Titan
·      Cassini spacecraft currently studying it
·      Rings are NOT solid; they are made of countless small chunks of ice and rock, each orbiting like a tiny moon.
Uranus
·      Smaller than Jupiter/Saturn; much larger than Earth
·      Made of H/He gas and hydrogen compounds (H2O, NH3, CH4)
·      Extreme axis tilt
·      Moons and rings
Neptune
·      Similar to Uranus (except for axis tilt)
·      Many moons (including Triton)
Neptune Pluto and Eris
·      Much smaller than other planets
·      Icy, comet-like composition
·      Pluto’s moon Charon is similar in size to Pluto
****What features of our solar system provide clues to how it formed? ****
Motion of Large Bodies
·      All large bodies in the solar system orbit in the same direction and in nearly the same plane.
·      Most also rotate in that direction.
Two Major Planet Types
·      Terrestrial planets are rocky, relatively small, and close to the Sun.
·      Jovian planets are gaseous, larger, and farther from the Sun.
Swarms of Smaller Bodies
·      Many rocky asteroids and icy comets populate the solar system. Notable Exceptions
·      Several exceptions to normal patterns need to be explained.
·      Swarms of Smaller Bodies
·      According to the nebular theory, our solar system formed from a giant cloud of interstellar gas.

****Where did the solar system come from? ****
·      Galactic Recycling
·      Elements that formed planets were made in stars and then recycled through interstellar space.
·      Evidence from Other Gas Clouds
·      We can see stars forming in other interstellar gas clouds, lending support to the nebular theory.
·      The Orion Nebula with Proplyds
****What caused the orderly patterns of motion in our solar system? ****
·      Orbital and Rotational Properties of the Planets Conservation of Angular Momentum
·      The rotation speed of the cloud from which our solar system formed must have increased as the cloud contracted.
·      Rotation of a contracting cloud speeds up for the same reason a skater speeds up as she pulls in her arms.
·      Collisions between particles in the cloud caused it to flatten into a disk.
·      Flattening Collisions between gas particles in a cloud gradually reduce random motions.
·      Formation of Circular Orbits Collisions between gas particles also reduce up and down motions.
****Why does the Disk Flatten? ****
·      The spinning cloud flattens as it shrinks.
·      Formation of the Protoplanetary Disk Disks Around Other Stars
·      Observations of disks around other stars support the nebular hypothesis.
****Why are there two major types of planets? ****
·      As gravity causes the cloud to contract, it heats up.
·      Conservation of Energy Collapse of the Solar Nebula Inner parts of the disk are hotter than outer parts.
·      Rock can be solid at much higher temperatures than ice.
·      Temperature Distribution of the Disk and the Frost Line
·      Inside the frost line: Too hot for hydrogen compounds to form ices Outside the frost line: Cold enough for ices to form
·      Formation of Terrestrial Planets
·      Small particles of rock and metal were present inside the frost line.
·      Planetesimals of rock and metal built up as these particles collided.
·      Gravity eventually assembled these planetesimals into terrestrial planets
·      Tiny solid particles stick to form planetesimals.
·      Summary of the Condensates in the Protoplanetary Disk Gravity draws planetesimals together to form planets.
·      This process of assembly is called accretion. Summary of the Condensates in the Protoplanetary Disk
·      Accretion of Planetesimals
·      Many smaller objects collected into just a few large ones.
·      Formation of Jovian Planets
·      Ice could also form small particles outside the frost line.
·      Larger planetesimals and planets were able to form.
·      The gravity of these larger planets was able to draw in surrounding H and He gases.
·      The gravity of rock and ice in jovian planets draws in H and He gases.
·      Nebular Capture and the Formation of the Jovian Planets Moons of jovian planets form in miniature disks.
·      Radiation and outflowing matter from the Sun — the solar wind — blew away the leftover gases. The Solar Wind
****Where did asteroids and comets come from? ****
·      Asteroids and Comets
·      Leftovers from the accretion process
·      Rocky asteroids inside frost line
·      Icy comets outside frost line Heavy Bombardment
·      Leftover planetesimals bombarded other objects in the late stages of solar system formation
·      Origin of Earth’s Water
·      Water may have come to Earth by way of icy planetesimals from the outer solar system.
***How do we explain the existence of our Moon and other exceptions to the rules?*
·      Captured Moons
·      The unusual moons of some planets may be captured planetesimals.
·      Odd Rotation
·      Giant impacts might also explain the different rotation axes of some planets.
·      Review of nebular theory
·      There are two main types of planets: terrestrial and jovian.
·      Planets orbit in the same direction and plane.
·      Asteroids and comets exist.
·      There are four terrestrial and four jovian planets.
·      There are two main types of planets: terrestrial and jovian.
·      Planets orbit in the same direction and plane.
·      Asteroids and comets exist.
·      There are four terrestrial and four jovian planets.
****When did the planets form? ****
·      We cannot find the age of a planet, but we can find the ages of the rocks that make it up.
·      We can determine the age of a rock through careful analysis of the proportions of various atoms and isotopes within it.
·      Radioactive Decay
·      Some isotopes decay into other nuclei.
·      A half-life is the time for half the nuclei in a substance to decay
·      Age dating of meteorites that are unchanged since they condensed and accreted tells us that the solar system is about 4.6 billion years old.
·      Dating the Solar System Dating the Solar System
·      Radiometric dating tells us that the oldest moon rocks are 4.4 billion years old.
·      The oldest meteorites are 4.55 billion years old.
·      Planets probably formed 4.5 billion years ago.

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