GLY 1000 Exam 1 Study Guide Chapter 1 Geocentric VS heliocentric Universe concepts o Geocentric Ancient Greek idea The sat motionless in the center of the universe while stars and other planets and the sun orbited around it Proposed by a Greek philosopher around 250 BCE All heavenly objects including the earth orbited the sun o Heliocentric Foucault s pendulum o Proves that earth spins on its axis o He set a heavy pendulum attached to a long string in motion As the pendulum continued to swing the plane in which it oscillated appeared to rotate around a vertical axis o This is due to Newton s first law of motion The circumference of the earth o Calculated by Greek astronomer Eratosthenes o The sun s rays at noon are exactly perpendicular to the earth s surface at Syene and since the earth is spherical then the sun s rays could not simultaneously be perpendicular to the earth s surface at Alexandria o Eratosthenes measured the shadow cast by a tower in Alexandria at noon so x 24421 miles this is within 2 of today s accepted value of 24865 miles o 360 x 7 2 5000 stradia Light years o The distance that light travels in one earth year o A light year is about 6 trillion miles Doppler effect energy passes an observer Red shift o The phenomenon in which the frequency of wave energy appears to change when a moving source of wave o The light of distant galaxies displayed red shifts relative to the light of nearby stars o Red shifts must be a consequence of the Doppler effect and thus that the distant galaxies are moving away from o But Hubble realized that the light from all distant galaxies exhibits a red shift because they are all moving rapidly earth at an immense velocity away from us Forming the planets and the earth moon system page 26 1 Nebular hypothesis A nebula forms from hydrogen and helium left over from the big bang 2 Gravity pulls gas and dust inward to form an accretionary disk and then the proto sun 3 Dust concentrates in the inner rings while ice concentrates in the outer rings then it become shot enough for a fusion reaction 4 Form planetesimal by colliding dust and ice 5 Planets form from planetesimals 6 Gravity reshapes the proto earth into a sphere 7 After the earth forms a small planet collides with it blasting debris that forms a ring around the earth 8 The moon forms from the debris 9 Atmosphere develops volcanic gases Supernova VS normal star o Supernova Short lived very bright object in space that results from the cataclysmic explosion marking the death of a very large star the explosion ejects large quantities of matter into space to form new nebulae o Normal star GLY 1000 Exam 1 Study Guide Inner VS outer planets o Inner planets Terrestrial planets earth like Mercury Venus earth and mars Consist of a shell of rock surrounding a core of iron alloys o Outer planets Jovian planets Jupiter like Gas giant planets Uranus and Neptune appear to consist predominantly of ice Jupiter and Saturn have an elemental composition similar to the sun Chapter 2 Magnetic field is a region affected by the force emanating from a magnet it grows progressively stronger as you approach the magnet and can cause charged particles to move o The solar wind interacts with the earth s magnetic field distorting it into a huge teardrop pointing away from the sun magnetosphere o The magnetic field acts like a shield against the solar wind the region inside the magnetic shield is called the o The Van Allen radiation belts 10500 to 300 km from earth consists of solar wind particles and cosmic rays that move fast enough that can penetrate the weaker outer part of the magnetic field and were then trapped by the stronger magnetic field closer to earth o Some charged particles interact with gas atoms in the upper atmosphere causing the gases to glow this is the aurorae Atmosphere o Earth o Venus o Mercury space o Mars Nitrogen 78 Oxygen 21 Other 1 consisting of argon carbon dioxide neon methane ozone carbon monoxide and sulfur dioxide Consist almost entirely of carbon dioxide Only a small trace of atmosphere because of the planet s high temperatures the atmosphere escaped into Thin atmosphere Primarily carbon dioxide Land and oceans o Humans cannot live for long at elevations greater than about 4 5 5 5 km they would die of suffocation GLY 1000 Exam 1 Study Guide o Land 30 o Surface water 70 o The hypsometric curve plots the surface elevation with the percentage of the earth s surface About 5 of earth s surface lies above 2km Most land lies less than 1km above sea level but the tallest mountain reaches 8 85km Most sea floor lays 4 to5km below sea level the deepest point reaches 11km Earth s composition o Iron 35 o Oxygen 30 o Silicon 15 o Magnesium 10 o The remaining 10 is the other 88 naturally occurring elements o Categories of earth materials Organic chemicals carbon containing compounds Minerals a solid substance in which atoms are arranged in an orderly pattern Glasses a solid in which atoms are not arranged in an orderly pattern Rocks aggregates of mineral crystals and grains and masses of natural glass Igneous hot molten rock cools and freezes Sedimentary grains from preexisting rocks become mented together Metamorphic undergo changes in response to heat and pressure Metals solids composed of metal atoms Alloy is a mixture containing more than one type of metal atom Melts solid materials become hot and transform into liquid Volatiles materials that are easily transformed into gas Oceanic crust Continental crust Moho crust mantle boundary discovery based on that the velocity of earthquake waves suddenly increased at a depth of about 50km this increase is caused by an abrupt change in the property of rock Approximately 0 1 to 1 0 of the earth s radius is the crust Earth s layers o Crust o Mantle Upper mantle Transition zone Lower mantle o Core Liquid outer core Solid inner core Earthquakes o Ground shaking due to the sudden breaking of rocks in the earth o Earthquake waves are vibrations they are seismic waves and they travel at different velocities through different materials Pressure and temperature inside the earth o Pressure and temperature increase with depth in the earth o Geothermal gradient is the rate of change in temperature with depth Lithosphere VS asthenosphere o Lithosphere Consist of crust and the uppermost part of the mantle The boundary is about 1280 C AT THE MANTLE ROCK BECME SSOFT ENOUGH TO FLOW GLY 1000 Exam 1 Study Guide o Asthenosphere Largely solid Chapter 3 Continental
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