Astronomy Chapter 18.1. Astronomy People in ancient cultures used the seasonal cycles to determine...
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Transcript of Astronomy Chapter 18.1. Astronomy People in ancient cultures used the seasonal cycles to determine...
Astronomy
• People in ancient cultures used the seasonal cycles to determine when they should plant and harvest crops.
• They built observatories to study the night sky.
• Over time, the science of Astronomy (the study of the Universe) was developed.
Modern Calendar• The modern calendar is based on the
observations of bodies in our solar system.• Day
– Amount of time it takes Earth to rotate once on it’s axis
• Month– Amount of time it takes the moon to orbit once around
the Earth
• Year– Amount of time it takes the Earth to orbit once around
the Sun
Ptolemy
• Claudius Ptolemy:– Greek Astronomer– (140 A.D.)– Believed in an Earth-
Centered Universe– Stated that the other
planets and the sun revolved around the Earth
– Helpful b/c he predicted motions of planets better than any other theory of the time
http://obs.nineplanets.org/psc/theman.html
Ptolemyhttp://player.discoveryeducation.com/index.cfm?guidAssetId=abd10202-edf5-434a-b525-03b3521088e9
Copernicus
• Nicolaus Copernicus:– Polish Astronomer– lived 1473 - 1543– Thought the sun is at
the center of the Universe
– All planets, including Earth, orbit the sun
– Very controversial & caused major changes in science and society
http://en.wikipedia.org/wiki/Copernicus
Copernicushttp://player.discoveryeducation.com/index.cfm?guidAssetId=abd10202-edf5-434a-b525-03b3521088e9
Brahe• Tycho Brahe
– Danish Astronomer– Lived 1546 - 1601– Stated the Sun and
Moon revolve around the Earth
– But other planets revolved around Sun
– Detailed astronomical observations
– Very precise observations of planets and stars.
http://galileo.rice.edu/sci/brahe.html
Brahehttp://player.discoveryeducation.com/index.cfm?guidAssetId=abd10202-edf5-434a-b525-03b3521088e9
Kepler
• Johannes Kepler– Lived 1571 - 1630– Brahe’s assistant– Did work on orbit of Mars
(because he and Brahe did not get along)
– Data ended up helping him prove that all the planets revolve around the sun in elliptical orbits
– Stated the three laws of planetary motion, still in use today
http://www-gap.dcs.st-and.ac.uk/~history/PictDisplay/Kepler.html
Keplerhttp://player.discoveryeducation.com/index.cfm?guidAssetId=abd10202-edf5-434a-b525-03b3521088e9
Kepler’s laws of planetary motion
• http://space.about.com/od/astronomybasics/tp/Keplers_Three_Laws.htm
• 1st law: planets travel in elliptical orbits with sun at one focus
• 2nd law: equal area law– http://physics.about.com/od/astronomy/p/keplerlaws.htm
• 3rd law: harmonic law P2 = D3
Galileo
• Galileo Galilei– 1564 - 1642– Italian scientist– One of the first to use
a telescopeDiscovered:craters and mountains
on the moon4 moons of JupiterSunspotsVenus’s phases
http://www-groups.dcs.st-and.ac.uk/~history/PictDisplay/Galileo.html
Copernicus and Galileohttp://player.discoveryeducation.com/index.cfm?guidAssetId=abd10202-edf5-434a-b525-03b3521088e9
Newton• Sir Isaac Newton
– 1643 - 1726– English Mathematician and
Scientist– Proved that all objects
attract each other through gravitational force.
– Force of Gravity depends on Mass and Distance of objects.
– Gravity holds moons and planets in orbit.
– Linked gravity & laws of planetary motion
http://www.horaz.com/horazyclopedia/Savoir/ARTICLES/Newton_Isaac.htm
Newtonhttp://player.discoveryeducation.com/index.cfm?guidAssetId=abd10202-edf5-434a-b525-03b3521088e9
Modern Astronomy
• Two milestones in modern astronomy– 1. Invention of the telescope– 2. Discovery of gravity
• Before the 1920’s, astronomers believed that our galaxy, the Milky Way, included every object in space.
Measuring the scale of the solar system
• http://player.discoveryeducation.com/index.cfm?guidAssetId=abd10202-edf5-434a-b525-03b3521088e9
Hubble
• Edwin Hubble– American Astronomer– Proved that other galaxies
existed, confirming that the universe is bigger than the Milky Way
– DID NOT develop the Hubble telescope. It was launched in 1990, Hubble died in 1953.
http://www.edwinhubble.com/hubble_bio_001.htm
Hubble Telescope• http://player.discoveryeducation.com/index.cfm?guidAssetId=abd10202-edf5-434a-b525-03b3521088e9