The Solar System

1
The Solar System

• The solar system is the sun and everything that
  revolves around the sun.

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Models of the Solar System

• Ancient Greeks the planets, sun and moon were
  on separate spheres that rotate
• The Greek word planasthai means to wander.
• This is called the Earth Centered Model of the
  solar system. ( The Earth is at the center of
  the universe.)

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The Sun Centered Model of the Solar System

• This is also known as the Heliocentric Model. (
  Helios the sun)
• Polish astronomer, Nicholas Copernicus, gave us
  the idea that the Earth goes around the sun in
  1543. WebSite

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Nicholas Copernicus
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Nicholas Copernicus
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Galileo Galilei Heliocentric Theory

• Italian astronomer, Galileo Galilei, found
  evidence that supported a Sun-Centered Model.
  Rice Universitys Galileo Project

Galileos Portrait by Tintoretto
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The Modern Model of the Solar System

• Our view of the solar system is constantly
  changing and improving .
• New moons have been discovered in 2005-2006.
• New Kuiper Belt Objects up to 2,100 miles across
  have been discovered recently.
• Eight planets and many large objects, over 100
  moons, asteroids, and comets orbit the sun.
• The sun is one of 400 billion stars in the Milky
  Way Galaxy. It is typical 200 extrasolar
  planets.

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A Theory for the Formation of the Solar System

• Scientist have evidence that the solar system was
  created out of a nebula 5 billion years ago.
• 1) 4.5 billion years ago, Gravity pulled matter
  inward, and the cloud contracted and began to
  spin.
• 2) Planets formed as particles collided over
  years.
• The sun formed at the center, and began nuclear
  fusion.

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Motions of the Planets

• In the 1600s, German mathematician, Johannes
  Kepler discovered that the planets orbit in an
  ellipse.
• The orbit of the planets is not a circle, but an
  oval or ellipse.
• Kepler discovered that the planets move at
  different speeds.

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The Inner Planets

• The Inner Planets are small and rocky, with iron
  cores.
• Mercury
• Venus
• Earth
• Mars

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Mercury
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Mercury

• The closest planet to the sun.
• The Messenger Probe is on its way to study
  Mercury. Launched Aug. 3, 2004,arrives March
  2011. Web
• Mariner 10 visited in 1975.
• There are 3 Km high cliffs that may indicate that
  Mercury shrank as its core cooled.
• There is a thin atmosphere of hydrogen and
  helium., sodium and potassium.
• The surface is 450 degrees C to 170 degrees C

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Venus

• Its size and mass are similar to Earth. WEB
• There is a dense atmosphere, 90 x the pressure
  of Earths. It is mostly carbon dioxide.

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Venus

• The gases create a greenhouse effect which keeps
  the temperature at 470 degrees C.
• The Russians sent many probes to Venus. The
  U.S.s Magellan was at Venus from 1990 to 1994,
  which showed craters, faults, and volcanoes with
  lava flows.

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Earth facts

• Earth is 1 AU ( astronomical unit ) from the sun.
• A key fact is that Earths temperatures allow
  water to exist as a solid, liquid, and gas.
• The Earths atmosphere protects life from the
  suns radiation.

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MARS Exploration
Viking 1976
Spirit Opportunity 2004-2006
Mars is red because iron oxide (rust) is on most
rocks on the surface of Mars.
Odyssey 2001
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Mars Exploration

• U.S. Mars Reconnaissance Orbiter arrived 3/06.
• MRO detected evidence of liquid water 12/06

Evidence of Water --------
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MRO 2006
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Mars Exploration Present and Future

• NASA Human Mission planned for 2030.

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Mars

• Mars has polar ice-caps. The northern cap is
  thought to be water, while the southern cap is
  frozen carbon dioxide.
• There are volcanoes, canyons, and deserts on Mars
• U.S. Pathfinder rover visited Mars in 1997.

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The Outer Planets

• Most of the outer planets are giant, gas and
  liquid planets. Most have many moons.
• Jupiter
• Saturn
• Uranus
• Neptune
• Pluto

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Jupiter
Signs of an ocean
Many Moons!
The Great Red Spot
Impacts from SL-9
The Moon Europa above a ring
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Jupiter

• Jupiter , The King, is the largest planet.
• Jupiter is made of hydrogen, helium, ammonia,
  methane, and water vapor.
• There may be a deep ocean of hydrogen and helium
  under the thick clouds of gas.
• TheGreat Red Spot is a storm which is bigger
  than Earth and has lasted at least 400 years.

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Moons of Jupiter

• Jupiter has 63 moons (as of 2006). Many have
  been discovered in the last few years.
• Galileo discovered the four largest in 1610,
• Io, Europa, Ganymede, and Callisto.
• Io has volcanoes.
• Europa has a thick ice crust, a thin oxygen
  atmosphere, and oceans, possibly more water than
  Earth.
• Ganymede is the largest moon in the solar system,
  larger than Mercury.

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Volcanoes on Io , the moon of Jupiter
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Europa Moon of Jupiter
NASAs Planet Web Site
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Saturn
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Giovanni Domenici Cassini
Italian astronomer who studied Saturn and
discovered several of its moons in the 1670s.
Web
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Saturn

• Saturn has massive rings made of rock and ice.
• There were 33 moons discovered by 2004.
• In 2005 , the Cassini probe visited Saturn.
• There are 56 moons as of December, 2006.
• Titan is the largest moon. It is bigger than
  Mercury. Its thick atmosphere appears orange. It
  has lakes of methane.

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Some of Saturns Moons
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Saturn
WEB NASA Facts

• Saturns density is so small that it would float
  on water.
• Saturn is a giant gas and liquid planet of
  hydrogen, helium, ammonia, methane, and water.
• Under the thick gas atmosphere, there may be a
  deep ocean. A rocky core may be at the center of
  Saturn.

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Saturn continued

• The Voyager probes visited Saturn in 1980 1981.
  
• The Cassini probe visited in 2004 - 2006

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Cassini Probe 2006

• The ESA probe, Huygens, discovered methane lakes
  on Saturns moon, Titan.
• Titan has a thick , Nitrogen gas atmosphere and
  appears orange.
• Cassini Probe Web Site
• Saturns Moons Web

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Uranus
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Uranus

• It was not discovered until 1781. Jupiter and
  Saturn were known in ancient times.
• There are 13 thin rings around Uranus (as of
  1/06).
• Uranus magnetic
• field is tilted 60 degrees
• from its rotational poles.

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Uranus

• The atmosphere is H, He, and methane. The
  methane gives it a blue-green color.
• Uranus has 27 moons as of 2005.
• The temperature is 216 degrees Celsius

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Neptune
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Neptune

• Neptune is another large gas planet, but it was
  only discovered in 1846.
• Sometimes Neptune is farther than Pluto.
• The atmosphere is similar to Uranus, and appears
  blue.
• There are dark blue features like the Great Red
  spot of Jupiter.

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Neptune

• The god of the sea may have oceans under its
  thick cloud cover. There probably is a rocky
  core.
• Voyager discovered six new moons , and the Hubble
  discovered more. The count for 2005 is 17 moons!
• Neptune has thin rings.
• Neptunes magnetic field is tilted 55 degrees.
• One ring appears to be twisted.

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Pluto
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Pluto Declassified 9/2006

• Pluto is a dwarf planet in the solar system.
• It is a Trans-Neptunian Object (TNO).
• Pluto has one large moon, Charon, and two other
  tiny moons, Nix and Hydra
• Pluto was discovered in1930, Charon in 1978. It
  was demoted Sept., 2006.
• JPL WebSite

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Plutos New Moons

• November, 2005 The candidate moons, Hydra and
  Nix , approximately 27,000 miles away from Pluto.
  The objects are roughly two to three times as far
  from Pluto as Charon. JPL/NASA web site