The sun, the earth, and the moon

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The sun, the earth, and the moon
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Our Solar Centre

• The Sun

• An Example of a Solar Tornado

• Has solar tornadoes
• A tall funnel of twisting plasma mmm!
• Can be 20,000km (diameter) and spins at
  500,000km/h
• Has a temperature of several million degrees
  Celsius

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The Sun a Typical Star

• Composed mainly of
• Hydrogen
• Helium
• Also has heavier elements
• Iron
• Carbon
• Oxygen
• Was born about 5 billion years ago, and will live
  for about 5 billion more years

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The Nature of the Sun

• Emits radiation in almost all forms found in the
  electromagnetic spectrum
• Visible light, UV radiation (causes sunburn)
• Its mass is estimated by observing how fast the
  planets, etc. orbit around it
• Nuclear reactions in the Sun are the same ones in
  the most powerful hydrogen bomb
• Hydrogen is converted into Helium (releases
  ENERGY)

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Layers of the Sun

• 6 main layers
• Core
• Inner part, temps at 15 million degrees Celsius
• Where nuclear fusion happens
• Radiative Zone
• Outside the core, dense plasma
• Light takes 100,000 years to pass through it
  (meaning...?)
• Convective Zone
• Big bubbles of hot plasma ooze up to surface,
  w/energy
• Cool plasma come down from surface to heat up
  again
• Constant circulation of plasma is called
  convection
• Photosphere
• Boundary between inside and outside of Sun,
  making it yellow
• What we see on Earth ? has the lowest temperature
  of 5500 degrees C
• Chromosphere
• Reddish, but cant see it unless theres a solar
  eclipse b/c of photosphere
• Corona
• Outermost layer, extends for millions of km most
  visible during solar eclipse

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Label Our Sun!! ?
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Surface Features of the Sun

• The Sun has a magnetic field
• Generated by movement of plasma deep in Sun
• It extends far out into space
• Very powerful

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Surface Features of the Sun

• Sunspots
• A region on surface of the Sun thats cooler than
  surrounding areas
• Where magnetic field is extremely strong
• This slows down convection ? no mixing of plasma
• Cools from 600oºC ? 4000ºC
• Every 11 yrs, max sunspots reached

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• Prominences
• A large, usually curved, bright stream of
  particles
• Extends out from photosphere into corona
• May last for many hours

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• Solar Flares
• Massive explosion at surface of Sun
• Interacts with chromosphere and corona
• Flings hot plasma into space

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• Coronal Mass Ejection
• Extremely powerful kind of flare
• Large amount of plasma is thrown out at 1000km/s
• Earths magnetic field protects us when this
  meets the Earth
• Causes auroras
• Can damage orbiting satellites and electrical
  transmission lines

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Learning Checkpoint

1. Which two elements make up more than 99 of the
   Sun?
2. Where in the Sun does nuclear fusion occur?
3. Name four types of surface features of the Sun.
4. How can a coronal mass ejection on the Sun cause
   damage on Earth?

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Suns Effects on Earth

• Solar Wind
• Constant flow of charged particles streaming out
  of the Suns surface in all directions
• Helped to create the solar system
• Electrical equipment can be damaged by this

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• Aurora Borealis (Northern Lights)
• Solar wind creates this display of green, yellow,
  and red light in the skies
• Aurora Australis (Southern Lights)
• Happens when charged particles of solar wind
  collide with atoms in Earths atmosphere
• Particles are trapped from solar wind in magnetic
  field and taken towards north and south poles

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How the Solar System Formed

• After Sun was formed (from what!?!?) the leftover
  dust, gases, etc. in nebula continued to spin
• This created a disk around the new star
• Bodies began to form
• Created our planets, moons, asteroids, comets
• This is how other star-and-planets systems formed
  too
• Planet a celestial object orbiting one or more
  stars can form a spherical shape
• DOES NOT create and radiate own light ? just
  reflects light of star(s) it orbits

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How the Solar System Formed
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Rocky Inner Planets

• Formed when spinning dust and gas slammed into
  each other and started sticking together
• Larger particles made more collisions and grew
  faster
• Gravity caused them to contract and bind together
• Objects too near the Sun got sucked into it
• Four large objects lasted Mercury, Venus, Earth,
  Mars

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Earths Moon
Mars is the only other rocky planet with moons!!

• Few hundred million years later...something as
  big as Mars may have hit the Earth
• Objects re-melted and mixed
• Metal core melded with Earths core
• Crusts melded together
• Earth cooled
• Pieces of debris from collision were caught by
  Earths gravity and eventually compacted into the
  Moon

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Asteroid Belt

• Between Mars and Jupiter
• Small as grains of sand 1000km across
• Scientists look for these near other stars
• Could indicate there are rocky planets there
  too!!
• This is where we got the age of the solar system
• Asteroids fell to Earth and oldest one was 4.56
  billion
• Earth was therefore formed at the same time
• Sun must have been around while earlier

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Gaseous Outer Planets

• Jupiter, Saturn, Uranus, Neptune
• After asteroid belt, snow line
• On Sun side of this line, its where Suns
  radiation keeps H2O in gas phase
• In snow line, waters cooled and forms droplets,
  then freezes
• Ice acted as a glue for gas and dust to stick
  together ? these planets grew faster!!
• All gas giants are orbited by many moons ?
  Jupiter and Saturn each have more than 60!!

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Minor Planets

• After gas giants, many large balls of ice formed
  ? minor or dwarf planets
• Pluto most famous
• 3 moons Nix and Hydra (tiny), and Charon (1/2
  Pluto)
• Millions of objects besides these orbiting the
  Sun
• Some larger, some smaller, than Pluto
• Create a thin disk like asteroid belt around
  entire solar system
• 25 of them are large enough to be considered
  minor planets

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Comets and Meteors

• Oort Cloud most distant region of SS, consisting
  of billions of fragments of ice and dust ? major
  source of comets
• Comet celestial object made of ice and dust
• Tail is created by sun heating and breaking apart
  some of the ice particles
• Meteoroid small pieces of rock/metal travelling
  throughout the solar system (no path)
• Meteor meteoroid that enters Earths atmosphere
  and begins to burn up because of FRICTION
• Meteorite a meteor that does not burn up
  completely and hits Earth

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Earth in Motion

• At equator 12 h daylight, 12 h night
• In Arctic some days, Sun doesnt set (summer)
  and some days, Sun doesnt rise (winter)
• What causes this?
• Tilt of the Earth on its axis

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Two Types of Motion

• Rotation

• Revolution

• One complete spin (counter clockwise) of the
  Earth on its AXIS
• Takes about 24h
• Earth moves at 1670 km/h
• Axis is tilted at 23.5º
• Creates day and night

• One complete orbit of Earth around the SUN
• Takes about 1 year
• Creates seasons
• Tilted axis revolution
• Tilted TO Sun summer
• Tilted AWAY FROM Sun fall

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Rotation and Revolution
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The Moon

• 1/6 Earths mass
• Also rotates on an axis
• Rotation and revolution are about equal
• 27.3 days, moon rotates and revolves once
• This is why we always see the same side of the
  moon
• Reflects Suns light ? changes in look (phases)
• One complete change of phases ? lunar cycle
• Full moon Earth between moon and sun
• New moon moon between Earth and sun

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Eclipses

• Solar Eclipse

• When moon blocks Suns light to Earth
• Two types
• Partial Sun is partially blocked
• Total Sun is completely blocked

• Lunar Eclipse

• When Earth blocks Suns light from shining on
  moon
• Two types
• Partial moon is partially blocked
• Total moon is completely blocked

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Tides

• The alternate rising and falling of level of
  oceans everyday
• Caused by
• Rotation of the Earth in the presence of the Moon
• Rotation of the Earth in the presence of the Sun
• Example Bay of Fundy
• Largest difference between high tide and tow tide
  levels (as much as 17 m in one day!)