Transcript Astronomy

Astronomy
The Solar System
Our solar system consists of one Sun,
eight planets, a few dwarf planets, and
many, many, moons.
 The solar system also contains asteroids,
meteors, meteorites, meteoroids and
comets to name a few.
 The solar system also has man made
items, also. Such as, satellites, rockets, a
space station, and “space junk.”
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THE SUN
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The Sun is the closest star to us
It is what gives us light and energy for life
It is 92 million miles away from Earth = one
astronomical unit (AU)
It is like a giant nuclear power plant, constantly
converting Hydrogen into Helium. (H -> He)
It will eventually die out once it loses its fuel
source, and the star will collapse
The Sun’s Interior
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The Core: the location in the center of the star
where the nuclear fusion is taking place
The Radiation Zone: middle layer where the
energy very slowly passes from the core
outward
The Convection Zone: outermost layer where
the hot gases rises from the RZ and cool and
then fall back towards the RZ—creating a
convection current
The Sun’s Interior
Features on the Sun
Sunspots: cool areas located on the Sun
 Prominences: loops of gas usually linking
groups of sunspots
 Solar Flare: connected prominences that
have so much energy that they are
released from the Sun out into space
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They can be seen as auroras on Earth
 They can disrupt our satellite links and cell
phone services
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Prominence
Prominence and Solar Flares
Sunspot
Auroras
Sun Spots
Solar flare: March 9, 2012
 http://abclocal.go.com/wpvi/video?id=8575
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Stars
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Stars are classified according to their color, temperature,
size, composition, and brightness.
Color: determined by the temperature
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(coolest) Red  Red-Orange  Yellow  White Blue (hottest)
0C
3000
4500
5750
10,000 50,000
Size: Even though they all appear the same to us, they can
be very different
Composition: Helium, Hydrogen, Sodium, Calcium
Brightness: depends on its size and temperature
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Apparent Brightness: Brightness as seen from Earth
Absolute Brightness: Brightness of the star if we were all at equal
distances to every star
The Hertzsprung-Russell Diagram
The EIGHT Planets
(plus Pluto)
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The Inner Planets
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Small and Rocky
Few or no Moons
Mercury
Venus
Earth
Mars
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The Outer Planets
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Large and gaseous
Many Moons
All have rings
Jupiter
Saturn
Uranus
Neptune
Planets’ orbits around the Sun
Poor Pluto
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Why doesn’t Pluto qualify as a planet?
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It’s too small
It doesn’t fit the pattern of a planet in that location in our
solar system
Its orbit is out of sync with the other planets
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It is now considered a DWARF PLANET
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Sometimes called a sub-planet
Mercury — Inner Planet
Smallest Planet
 Closest to the Sun
 Has virtually no atmosphere, which is why
it has so many craters
 Moon: none
 Day: 59 Earth days
 Year: 0.24 Earth Year
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( about 88 days)
Venus — Inner Planet
Very similar is size and shape to Earth, so
it is sometimes called “Earth’s Twin”
 Its atmosphere is so thick its always
cloudy, but those clouds are acidic!
 Moon: none
 Day: 243 Earth days
 Year: 0.62 Earth Years
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( 226 days)
Earth — Inner Planet
Rocky planet with an atmosphere which is
mostly Nitrogen
 Only planet with Life
 Only planet with
liquid water
 Moon: one
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Mars — Inner Planet
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The RED PLANET
The atmosphere is 95% CO2.
The planet has extreme temperature
differences…70oF during the day and
-225oF at night!
Mars also is tilted like Earth, so it too
has seasons
Location we are planning on making a
space station in the near future
Moons: two
Day: 24.7 Earth hours
Year: 1.9 Earth Years
(693 Earth Days)
Asteroid Belt
The inner planets and the outer planets
are separated by an asteroid belt
 An asteroid is a small rocky substance
that orbits the Sun
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Jupiter – Outer Planet
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Largest Planet
Thick atmosphere made out
of Hydrogen and Helium
Probably has a dense core,
but most of the planet is
gaseous
Has rings
Moons: 60+
Day: 10 Earth Hours
Year: 12 Earth Years
Saturn—Outer Planet
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Second largest planet in
the solar system
Well known for its system
of rings
Gaseous planet made out
of Helium and Hydrogen
Moons: 31+
Day: 11 hours
Year: 29 years
Uranus—Outer Planet
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Also a gaseous planet, with traces of methane
which makes it blue-green
It axis of rotation is tilted so it rotates head over
heel instead of spinning like a top
Does have rings
Moons:13+
Day: 16 hours
Year: 84 Earth Years
Neptune –Outer Planet
Cold, blue planet
 It has clouds and storms,
but not with water like
ours
 Does have rings
 Moons: 13+
 Day: 16 hours
 Year: 164 years
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Meteors/Meteorites/Meteroids
Meteoroid: free floating rock in outer space
 Meteor: rock fragments burning as they
make there way through our atmosphere;
we see them as “Shooting Stars”
 Meteorite: If there are any pieces of rock
that make it to the ground, the remaining
piece is called a meteorite
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Meteor or shooting star
Crater caused by meteorite
Meteorites on Mars
Black Holes
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An object in space whose gravity is so
strong that not even light can escape
Comet
A comet is a ball of dust and ice that
orbits the Sun
 Sometimes called a “Dirty Snowball”
 The most famous is Halley’s Comet that
appears every 76 years, due in 2062,
(last seen in 1986, next seen in 2062)
 The last comet we could see was HaleBopp in 1997
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Comets
Halley’s Comet
Hale-Bopp 1997
Seasons
The seasons on Earth are due to the tilt of
the Earth, NOT how close we are to the
Sun.
 We are actually closest to the Sun in the
Winter, but the Northern Hemisphere is
tilted away from the sun, so we receive
less direct Sun rays.
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Tilt of the Earth causes Seasons
During the winter, we are tilted AWAY from the Sun.
During the summer, we are tilted TOWARDS the Sun
Distance of Earth to the Sun during
its Orbit
We are CLOSER to the Sun on January 2nd than on July 2nd
Size Comparisons
Size Comparisons
Size Comparisons
Size comparisons
History of the Earth in 2 minutes
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Video clip