Astronomy Earth ’ s Place in the Universe

Agree or Disagree? ___ Kepler discovered that the path of each planet around the sun is an ellipse. ___ The universe is made of galaxies, galaxies contain stars, stars may have planetary systems. 2

What is Astronomy? The science that studies the universe that deals with The science that studies the universe that deals with Properties of objects in space Properties of objects in space Laws under which the universe operates Laws under which the universe operates

Famous Astronomers The Ancient Greeks The Ancient Greeks Ptolemy Ptolemy Copernicus Copernicus Brahe Brahe Kepler Kepler Galileo Galileo Newton Newton

Famous Astronomers Ancient Greeks Ancient Greeks Geocentric view (Earth centered) Geocentric view (Earth centered) 7 heavenly bodies (Sun, Moon, Mercury – Saturn) and stars 7 heavenly bodies (Sun, Moon, Mercury – Saturn) and stars Aristachus – Heliocentric (Sun centered), retrograde motion Aristachus – Heliocentric (Sun centered), retrograde motion Ptolemy: 141 AD Ptolemy: 141 AD Geocentric Model Geocentric Model Copernicus: 1473 – 1543 Copernicus: 1473 – 1543 Earth was a planet Earth was a planet Model of the Solar System – Sun centered - heliocentric Model of the Solar System – Sun centered - heliocentric

Famous Astronomers Brahe : 1546 – 1601 Brahe : 1546 – 1601 Solar Eclipses Solar Eclipses Geocentric universe Geocentric universe Galileo: 1564 – 1642 Telescope in moons of Jupiter Sunspots Newton: 1643 – 1727 Newton: 1643 – 1727 Law of Universal Gravitation (Gravity) Law of Universal Gravitation (Gravity) 3 Laws of Motion (Inertia, forces, action/reaction) 3 Laws of Motion (Inertia, forces, action/reaction) Supported Kepler Supported Kepler Father of calculus Father of calculus

Famous Astronomers ✤ Kepler: 1571 – 1630 ✓ 3 Laws ✓ 1st law: The orbits of the planets are ellipses, with the Sun at one focus of the ellipse. ✓ 2nd law: The line joining the planet to the Sun sweeps out equal areas in equal times as the planet travels around the ellipse. ✓ 3rd law: The ratio of the squares of the revolutionary periods for two planets is equal to the ratio of the cubes of their semimajor axes.

History of the Universe History of the Universe Big Bang theory Big Bang theory States that at one time, the entire universe was confined to a dense, hot, super-mass ball States that at one time, the entire universe was confined to a dense, hot, super-mass ball About 13.7 billion years ago, a violent explosion occurred, hurling this material in all directions About 13.7 billion years ago, a violent explosion occurred, hurling this material in all directions Marks the beginning of the universe Marks the beginning of the universe

9 Nebula Theory Theory of how the bodies of our solar system evolved from an enormous rotating cloud called the solar nebula. Made up of Hydrogen and Helium Theory how the planets were formed 8

10 The Expanding Universe Theory The Expanding Universe Theory, developed from the observed red shifts of celestial bodies, that the space between galaxies is expanding, so that they appear to recede from us at velocities that increase with their distance 9

Types of Galaxies Spiral Spiral Disk-shaped with concentration of stars in the center and “ arms ” extending from the center Disk-shaped with concentration of stars in the center and “ arms ” extending from the center Contain old and young stars Contain old and young stars Ex) Milky Way Galaxy Ex) Milky Way Galaxy) Milky Way Galaxy) Milky Way Galaxy Elliptical Elliptical Round to oval in shape Round to oval in shape Contain old stars Contain old stars Ex) giant diffuse galaxies -largest Ex) giant diffuse galaxies -largest Irregular Irregular No definite shape No definite shape Composed of young stars Composed of young stars Ex) Large and Small Magellanic Clouds (closest neighbor galaxies) Ex) Large and Small Magellanic Clouds (closest neighbor galaxies)

Agree or Disagree? ___ Kepler discovered that the path of each planet around the sun is an ellipse. ___ The universe is made of galaxies, galaxies contain stars, stars may have planetary systems. 12

13 End of day one!

Agree or Disagree? Electromagnetic radiation includes gamma rays, X-rays, ultraviolet light, visible light, infrared radiation, microwaves and radio waves. Nuclear fission and fusion are the same thing. Sunlight is used in the process of photosynthesis for plants and other autotrophs to make energy. Any living thing could exist without sunlight. 14

The Sun The Sun Solar Interior or Core Solar Interior or Core The Sun produces energy by a process known as nuclear fusion The Sun produces energy by a process known as nuclear fusion Convection currents occur here Convection currents occur here Enough fuel to last another 5 billion years Enough fuel to last another 5 billion years

Fusion and Fission Fusion Particles “Fuse” together to create energy Found on the Sun and Stars Fission Particles split to create energy Found in Nuclear Reactors splitting atoms to create energy 16

17 Energy from the Sun Solar energy into chemical energy through photosynthesisphotosynthesis Plants use sunlight to produce sugar through the actions of the chlorophyll Chemical Formula 6H 2 O + 6CO > C 6 H 12 O 6 + 6O 2 30

18 How does the magnetic field protect us from harmful solar radiation rays?

Agree or Disagree Revolution is the motion of a body along a path around some point in space. Rotation is the turning, or spinning, of a body on its axis. Barycenter is the center of mass between celestial objects. Nutation is the wobble movement observed in precession. 19

Agree or Disagree Precession is a slow movement in rotation of a body on its axis. Earth’s revolution results in day and night. One Earth around rotation the sun is a year. Seasons on Earth are due to the Earth’s rotation around the Sun. Seasons of the Northern and Southern hemisphere are opposite. 20

Light Electromagnetic radiation (spectrum) Electromagnetic radiation (spectrum) Gamma rays - fastest Gamma rays - fastest X-rays X-rays UV rays UV rays Visible spectrum (ROYGBIV) Visible spectrum (ROYGBIV) Infrared waves Infrared waves Radio waves – slowest Radio waves – slowest Electromagnetic Spectrum: The arrangement of these waves according to their wavelengths and frequencies Electromagnetic Spectrum: The arrangement of these waves according to their wavelengths and frequencies

Light: Wave or Particle? Wave: Found on Earth Wave: Found on Earth Particle: Photons found in space Particle: Photons found in space

Spectroscopy Study of the properties of light that depend on wavelength. Study of the properties of light that depend on wavelength. Visible white light passes through a prism producing the colors of the rainbow (ROYGBIV) Visible white light passes through a prism producing the colors of the rainbow (ROYGBIV)ROYGBIV

Rotation The turning or spinning of a body on its axis The turning or spinning of a body on its axis Causes day and night Causes day and night Two kinds of measurement Two kinds of measurement Mean Solar Day – time interval from one noon to the next (24 hours) Mean Solar Day – time interval from one noon to the next (24 hours) Sidereal Day – time it takes for Earth to make one complete rotation (360 ’ ) with respect to a star other than the sun (23 hours, 56 minutes, 4 seconds) Sidereal Day – time it takes for Earth to make one complete rotation (360 ’ ) with respect to a star other than the sun (23 hours, 56 minutes, 4 seconds)

Revolution Motion of a body along a path around some point in space. Motion of a body along a path around some point in space. Earth ’ s orbit is elliptical Earth ’ s orbit is elliptical Earth ’ s distance from the sun varies Earth ’ s distance from the sun varies Perihelion Perihelion –Earth is closest to the sun –147 million km away –Occurs on January 3rd Aphelion Aphelion –Earth is farthest from the sun –152 million km away –Occurs on July 4th

Precession slight movement, over a period of 26,000 years where Earth ’ s axis points in different directions slight movement, over a period of 26,000 years where Earth ’ s axis points in different directions Points to two stars Points to two stars Polaris Polaris Vega Vega Currently pointing to Polaris Currently pointing to Polaris Doesn ’ t affect the seasons Doesn ’ t affect the seasons

27 Nutation and Barycenter Nutation oscillatory movement of the axis of a rotating body or a wobble occurs about 18.6 years Barycenter the point between two objects where they balance each other the center of mass where two or more celestial bodies orbit each other Barycenter website with animation Barycenter website with animation

 Seasons are caused by the tilting of the earth on its axis Seasons  When the Earth is tilted towards the Sun – warmer seasons  When the Earth is tilted away from the Sun – cooler seasons

29 How would you describe the Earth ’ s shape and appearance? What affects its shape? 17

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Agree or Disagree Tides are only caused by the Sun’s magnetic pull. 31

What are Tides? changes in elevation of the ocean surface What causes Tides? Gravitational forces of the moon and sun

Tidal Range Vertical distance between the high and low tides. Vary from place to place and week to week.

Spring Tides Occur during the new and full moons All gravitational forces are added together Extreme high and low tides High tidal range

Neap Tides During the 1 st and 3 rd quarters of the Moon Gravitational forces are offset Tidal range is the smallest value

Tides Tides occur 50 minutes later due to … Rotation pattern of earth and moon. This is known as a lunar day

Tidal Patterns Diurnal (daily) one high and one low tide each lunar day. Occurs at Pensacola, Fl. And the Gulf coast. Semidiurnal (semi-daily) 2 high and 2 low tides: each high and low tides are similar to the preceding high and low. Occurs in the Atlantic coast Mixed 2 high and 2 low tides each day. Each high and low tides are different from each other. Occurs on the west coast.

38 End of Astronomy Unit! 32