Astronomy NotesEssay Preview: Astronomy NotesReport this essayAstronomy  day/night -> earth spins on axis, repetition of stars and sun very night we see the shape of the moon change.Lunar phases are a consequences of the moons 27.3 orbit around earth (sidereal)Phases of moon  29.5 day cycle (synodic)Which is it ? both depends on reference point Synchronous rotation; the celestial body rotates exactly once with each orbit. When we only see one side of the moon. The moon revolves around us and we only see the one face.What causes eclipse, earth and moon cast shadowsSolar eclipse: moon blocks sun from part of earth, happens at new moon.Three types: total: completely blocks sun                  Partial: on part of sun is blocked                  Annular: the sun appears as a bright ring around the moonLunar eclipse: happens at full moon, earth is between sun and moon. Visible over more of earth, last longer then solar.When you have solar eclipse, two weeks later you will have lunar.Chapter 2 can be called motion gravity and energyChapter 3 laws of motion: we find out ancient mysteries of the planets. How this all started. Greek astronomy: they observed the celestial bodies revolving around them.Ptolemy had most sophisticated version of the geocentric model, used for 1500 yearsPlato and Aristotle were the first to say earth is the center and the heavens are a perfect circle around us Geocentric model says that everything revolves around us, earth was the center the centerRetrograde motion 1 planets usually move Potolemaic model 1 sun rises orbiting earth 2 moon rises and sets 3 stars rise and set together, rotating about point, centered on earth. Parallax , and apparent shift in the relative coppostions of 2 objects when viewed from different perspectives   Copernicus center of solar system is near the sun 1543. Parallax earth sun distance << distance to stars. The apparent retrograde motion is caused by motion of planets around sun. copernicun/heliocentric model = center around the sun. The planets follow circular orbits around the sun. Tycho brahe compiled most precise measurements of planets positions for his time, with no telescope. Observed supernova (1572), showed it was at distance of stars. Parallax view. He hired Johannes kepler (1571-1630)Tychos invention: a human sized quadrant Brahe assigned him the tough problems of mars retrograde motion. Found that planetary orbits were heliocentric and elliptical (not circular)Keplers first lawthe orbit of each planet is an ellipse with the sun at one focusKeplers second law  the law of equal areas. As a planet moves around its orbit it sweeps out equal areas in equal times.  Areas: A = B = C ….. time of A = time of B = time of CKeplers third lawthe time for planets to orbit the sun is related to its distance from the sun: P squared = a cubed Galileo 1564-1642 “the astronomer”Believed Copernican model.Demonstrated that keplers and Copernicus ideas were right with his telescope.1 the heavens aren’t perfect-the sun had spots-the moon had geological features 2 moons of Jupiter obey keplers law-saw four moons orbiting Jupiter, proving not all objects orbit earth.3 phases of venus, supporting heliocentric theory4 observed that mars, Jupiter and Saturn had no phases5 observed individual stars in miky way.Galileo study on motionMuseum in munich GermanyHow to describe motionSpeed: rate at which object moves Velocity: speed and directionAcceleration: any change in speed and direction Isaac newton1 Invented calculus as necessary tool to solve math problems related to motion2 Formulated 3 laws of motion3 Formulated 3 universal law of mutual gravitationuniversal law of gravitation1 every mass attracts other mass2 attraction is directly proportional to the product of their masses 3 attraction is inversely proportional to the square of the distance between their centersmass is the amount of matter on the object weight Is the amount of force on the objectTwo types of energykinetic energy is motionpotential energy is storedenergyENERGY CANNOT BE DESTROYEDKINETICelectrical- chargesradiant- EM energythermal- heatmotion- newtons lawsound-POTENTIALChemical- stored in bondsStored chemical- springsNuclear- stored in nucleusEnergy transformationsChemical -> motionEtc.Mass-energyMass itself is a form of potential energyE=mc squaredUniversal law of gravitation1 every masss attracts another mass

E.dynamic- energyEnergy is a measure of your own kinetic energy2 a heat wave is proportional to angular momentum of each point of the wave(a)The intensity of a wave is the volume of energy in a cubic centimetre*dynamic energy is an electric-type particleenergy is a constant of the radius of a circle (2.5×3)where is the quantity of energy per particle of energy on the point.The magnitude of the intensity is a function of your particle(energy per unit volume) and is the quantity of the quantity in seconds.energy, energy, energydynamic=0.1/dynamic energy – 1.5 energy-energy (which is the energy mass of the object being studied in the second study)-energy, energy, energy-energy-energy*dynamicenergy, energy-energy-energy-1.5 energy = (1.052/10-1)1.35Dynamically unstable(see 2 for more)
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