Download The sun, the earth, and the moon

THE SUN, THE EARTH, AND THE
MOON
Our Solar Centre
The Sun
 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
An Example of a Solar Tornado
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
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)
Layers of the Sun
 6 main layers:
Core
1.


Inner part, temps at 15 million degrees Celsius
Where nuclear fusion happens
Radiative Zone
2.


Outside the core, dense plasma
Light takes 100,000 years to pass through it (meaning...?)
Convective Zone
3.



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
4.


Boundary between inside and outside of Sun, making it yellow
What we see on Earth  has the lowest temperature of 5500 degrees C
Chromosphere
5.

Reddish, but can’t see it unless there’s a solar eclipse b/c of photosphere
Corona
6.

Outermost layer, extends for millions of km; most visible during solar eclipse
Label Our Sun!! 
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
Surface Features of the Sun
 Sunspots
 A region on surface of the
Sun that’s 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
 Prominences
 A large, usually curved,
bright stream of
particles
 Extends out from
photosphere into corona
 May last for many hours
 Solar Flares
 Massive explosion at
surface of Sun
 Interacts with
chromosphere and
corona
 Flings hot plasma into
space
 Coronal Mass Ejection
 Extremely powerful kind




of flare
Large amount of plasma is
thrown out at 1000km/s
Earth’s magnetic field
protects us when this
meets the Earth
Causes auroras
Can damage orbiting
satellites and electrical
transmission lines
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?
Sun’s Effects on Earth
1. Solar Wind



Constant flow of
charged particles
streaming out of the
Sun’s surface in all
directions
Helped to create the
solar system
Electrical equipment
can be damaged by
this
Aurora Borealis (Northern
Lights)
2.




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 Earth’s atmosphere
Particles are trapped from solar
wind in magnetic field and taken
towards north and south poles
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
How the Solar System Formed
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
Earth’s 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 Earth’s core
 Crusts melded together
 Earth cooled
 Pieces of debris from collision were caught by
Earth’s gravity and eventually compacted
into the Moon
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
Gaseous Outer Planets
 Jupiter, Saturn, Uranus, Neptune
 After asteroid belt, “snow line”
 On Sun side of this line, it’s where Sun’s radiation
keeps H2O in gas phase
 In snow line, water’s 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!!
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
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 Earth’s atmosphere
and begins to burn up because of FRICTION
 Meteorite: a meteor that does not burn up completely
and hits Earth
Earth in Motion
 At equator: 12 h daylight, 12 h night
 In Arctic: some days, Sun doesn’t set (summer)
and some days, Sun doesn’t rise (winter)
 What causes this?
 Tilt of the Earth on its axis
Two Types of Motion
Rotation
Revolution
 One complete spin
 One complete orbit of




(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
Earth around the SUN
 Takes about 1 year
 Creates seasons
 Tilted axis + revolution
 Tilted TO Sun = summer
 Tilted AWAY FROM Sun = fall
Rotation and Revolution
The Moon
 1/6 Earth’s 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 Sun’s 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
Eclipses
Solar Eclipse
 When moon blocks Sun’s light
to Earth
 Two types
1.
2.
Lunar Eclipse
 When Earth blocks Sun’s light
Partial: Sun is partially blocked
from shining on moon
Total: Sun is completely blocked  Two types
1.
2.
Partial: moon is partially blocked
Total: moon is completely blocked
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!)