Observing the Solar System Chapter 14.1 [p. 538]

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Observing the Solar SystemChapter 14.1 p. 538
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Early Ideas of the Solar System

• The Greeks thought that they were inside a
  rotating dome they called the celestial sphere.
• The Greeks also thought that the universe was
  perfect and unchangeable.
• Earth is stationary the Greeks thought we are in
  a geocentric system
• The Earth is at the center of the revolving
  planets.

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Early Ideas Cont.

• In 140 A.D. Ptolemy
• theorized that the planets moved on little
  circles that move on bigger circles, this
  explained why the planets moved at different
  speeds.
• Ptolemys geocentric model of the planets was
  widely held for nearly 1,500 years after his
  death

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Early Ideas Cont.

• 1500s Nicolaus Copernicus
• 1543, Copernicus came up with a theory that would
  revolutionize the science of astronomy The
  Copernican Revolution
• In a heliocentric system the sun is at the center
  and the planets revolve around the sun.

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Early Ideas Cont.

• 1600s Galileo
• Galileo was the1st scientist to use a telescope
  to look at objects in the sky.
• Galileo made 2 discoveries that supported the
  heliocentric theory
• Venus goes through phases similar to Earths
  moon. These phases could not be explained if
  Earth was the center of the system.
• Jupiters moons revolved around Jupiter.
  Therefore not everything in the sky revolved
  around Earth.

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Early Ideas Cont.

• Late 1500s - 1600s
• Tycho Brahe
• Observed the positions of the planets for 20 yrs.
• Johannes Kepler
• Kepler analyzed Brahes data to determine the
  shape of the orbits.
• He discovered the orbits are elliptical in shape.

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Keplers Three Laws

• First Law Planets move in ellipses, not circles

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Keplers Three Laws

• Second Law A planet moves faster when closer to
  the sun, slower when away

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Keplers Three Laws

• Third Law Planets closer to the sun move faster
  than planets farther from the sun

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Early Ideas Cont.

• 1665Newton
• Newton stated that two factors keep the planets
  in orbit
• Inertia and gravity
• Gravity attracts all objects toward each other
• The strength of gravity depends on the mass of
  the objects and the distance between them.
• Inertia The tendency of a moving object to
  continue in a straight line or a stationary
  object to remain in place
• The more mass and object has, the more inertia it
  has.

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Components of our Solar System

• Planets
• Stars
• Comets
• Asteroids
• Satellites
• Space Trash
• Dark Matter
• Particles (Dust)
• Electromagnetic radiation (Photons)

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Planets

• There are 8 planets
• Mercury
• Venus
• Earth
• Mars
• Jupiter
• Saturn
• Uranus (YOOR uh nus)
• Neptune
• Pluto

Terrestrial Planets
Gas Giants
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Astronomical Unit

• 1 AU (astronomical unit) the Earths average
  distance from the sun (about 150 million
  kilometers or about 93 million miles)

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How We Look Into Space!

• We can see far into space with the help of
  telescopes, satellites and spectroscopes.
• There are many types of telescopes, most of which
  collect and focus electromagnetic radiation,
  including visible light.

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Telescopes

• Visible Light Telescopes
• Reflecting Telescope
• 1668 Isaac Newton built this type of telescope.
• Used a mirror instead of an objective lens.
• Focuses a large amount of light onto a small
  area.
• Refracting Telescope
• 1609 Galileo used this type of telescope to look
  into space.
• Uses a convex lens to gather large amount of
  light and focus in onto a small area.

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Telescopes Cont.

• Radio Telescopes
• Used to detect radio waves from objects in space.
• Have curved surfaces, up to 305m in diameter
• Surfaces concentrate faint radio waves from space
  onto small antennas like those on radios.
• The larger the telescope is, the more radio waves
  it can collect.

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Telescopes

• Infrared Telescopes
• Detect longer wavelengths than visible light
• A building that contains 1 or more telescopes is
  called an observatory.

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Telescopes

• 1897 Yerkes Telescope
• 1m in diameter
• Largest refracting telescope ever built
• The lens is so large, it can collect more light
  than any other refracting telescope
• 1931 Karl Jansky
• Accidentally discovered radio astronomy
• Tried to figure out what static was interfering
  with radio communications. The static was coming
  from objects in space!

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Telescopes

• 1963 Arecibo radio telescope
• Built in a natural bowl in the ground
• It is 305m in diameter
• Located in Puerto Rico
• 1980 The Very Large Array
• 27 radio telescopes in New Mexico
• They can be moved close together or far apart
• They are linked together, so they can be used
  individually or as one giant telescope 25km in
  diameter.

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Telescopes

• 1996 Keck Telescopes
• 2 of the largest reflecting telescopes
• Located in Hawaii
• Each telescope is made of 36 smaller mirrors
  joined together to make one 10m curved mirror.

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Satellites

• Most UV radiation, X-rays, gamma rays are
  blocked by the Earths atmosphere.
• In order to detect these wavelengths, astronomers
  have placed telescopes on satellites and launched
  them into space.

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Satellites

• 1990 Hubble Space Telescope
• HAPPY BIRTHDAY HUBBLE!!!!!!!
• Launched April 24, 1990
• Can see objects in space more clearly than any
  other telescope.

Large Ant Nebula
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Homework

• Read Section One of Chapter 14
• Do the questions at the end of the section, page
  544 1a,b,c,d 2a,b,c 3a,b,c