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... Astronomical distances are so large that we use the speed of light to measure them Mean Earth-Sun Distance – 150 million Km = 1 Astronomical Unit (AU) = 8.3 Light Minutes 1 Light Year (Ly) = 9.5 trillion Km = 63,240 AU Parsec = 3.26 Lys (parallax angle unit) ...
... Astronomical distances are so large that we use the speed of light to measure them Mean Earth-Sun Distance – 150 million Km = 1 Astronomical Unit (AU) = 8.3 Light Minutes 1 Light Year (Ly) = 9.5 trillion Km = 63,240 AU Parsec = 3.26 Lys (parallax angle unit) ...
Lecture 2 - University of Chicago, Astronomy
... His discoveries were written down in his book called Starry Messenger. Luckily to us all, he wrote it in his native language, Italian, rather in the scholar language of the day, Latin. Had he done otherwise, me may have been using a Latin textbook for this class! However, his most important contribu ...
... His discoveries were written down in his book called Starry Messenger. Luckily to us all, he wrote it in his native language, Italian, rather in the scholar language of the day, Latin. Had he done otherwise, me may have been using a Latin textbook for this class! However, his most important contribu ...
Geocentric vs. Heliocentric
... 1632: "Dialogo Dei Massimi Sistemi" (In Italian! Not Latin! For the common people!) He published his masterpiece, Dialogue on the Two Chief World Systems, in which he had two people, one representing the view of Ptolemy and other the view of Copernicus, present their arguments before an intelligent ...
... 1632: "Dialogo Dei Massimi Sistemi" (In Italian! Not Latin! For the common people!) He published his masterpiece, Dialogue on the Two Chief World Systems, in which he had two people, one representing the view of Ptolemy and other the view of Copernicus, present their arguments before an intelligent ...
Lecture 3 Ptolemy to Galileo
... ● discovered precession of the equinoxes ● determined: obliquity of the ecliptic ● synodic periods of planets ● inclination of Moon's orbit ● place of Sun's “apogee” ● eccentricity of the “Sun's orbit” ● estimate of the Moon's distance, using the diameter of the Earth as a baseline ● He put ...
... ● discovered precession of the equinoxes ● determined: obliquity of the ecliptic ● synodic periods of planets ● inclination of Moon's orbit ● place of Sun's “apogee” ● eccentricity of the “Sun's orbit” ● estimate of the Moon's distance, using the diameter of the Earth as a baseline ● He put ...
Study Guide for 1ST Astronomy Exam
... o Location of the planets and the observational basis for that ordering. (See Figure 11.10) Describe the cause of retrograde motion in our modern Copernican Model. Describe why inferior planets demonstrate a maximum elongation in their motion. Describe how Copernicus determined the relative d ...
... o Location of the planets and the observational basis for that ordering. (See Figure 11.10) Describe the cause of retrograde motion in our modern Copernican Model. Describe why inferior planets demonstrate a maximum elongation in their motion. Describe how Copernicus determined the relative d ...
Nearby Constellations
... Half-hour time exposure facing north & west. The stars are tracing counter-clockwise circles, centered on a point near the prominent North Star (Polaris). Notice the Big Dipper at the lower-left. ...
... Half-hour time exposure facing north & west. The stars are tracing counter-clockwise circles, centered on a point near the prominent North Star (Polaris). Notice the Big Dipper at the lower-left. ...
Lecture 3 Geocentrism vs.Heliocentrism
... Planets on physical spheres – each moving the other – earth and sphere of prime mover stationary ...
... Planets on physical spheres – each moving the other – earth and sphere of prime mover stationary ...
Sir Isaac Newton
... Hipparchus had a problem making his star chart. It was easy enough to map the surface of the Earth, because the Earth has landmarks: rivers, mountains, cities--places of known location, to which other places can be compared. The sky, however, has no landmarks, just the stars themselves. Hipparchus d ...
... Hipparchus had a problem making his star chart. It was easy enough to map the surface of the Earth, because the Earth has landmarks: rivers, mountains, cities--places of known location, to which other places can be compared. The sky, however, has no landmarks, just the stars themselves. Hipparchus d ...
Planetarium Key Points
... Using a motionless sphere we can define a great circle, the horizon, and its poles, zenit and nadir 2. The daily motion of the sphere All the sky moves from Est to West around an axis that seems fixed on the sphere (for short periods of time as human life) The motion and the sphere define two ...
... Using a motionless sphere we can define a great circle, the horizon, and its poles, zenit and nadir 2. The daily motion of the sphere All the sky moves from Est to West around an axis that seems fixed on the sphere (for short periods of time as human life) The motion and the sphere define two ...
Greek Astronomy - Galileo and Einstein
... Crystal Spheres: Plato, Eudoxus, Aristotle Plato, with his belief that the world was constructed with geometric simplicity and elegance, felt certain that the sun, moon and planets, being made of aither, would have a natural circular motion, since that is the simplest uniform motion that repeats its ...
... Crystal Spheres: Plato, Eudoxus, Aristotle Plato, with his belief that the world was constructed with geometric simplicity and elegance, felt certain that the sun, moon and planets, being made of aither, would have a natural circular motion, since that is the simplest uniform motion that repeats its ...
Ancient Astronomy
... In 1572 observed a Super Nova – no parallax found (over night) Can’t be a star – heavens unalterable – must be near Earth In 1577 observed a comet – no parallax found Observed other stars – no parallax found Concluded Copernicus was wrong - Earth did not move Danish King built him the “Sky Castle” S ...
... In 1572 observed a Super Nova – no parallax found (over night) Can’t be a star – heavens unalterable – must be near Earth In 1577 observed a comet – no parallax found Observed other stars – no parallax found Concluded Copernicus was wrong - Earth did not move Danish King built him the “Sky Castle” S ...
angular size - Particle and Astroparticle Physics
... • In the 1860s, the Scottish mathematician and physicist James Clerk Maxwell succeeded in describing all the basic properties of electricity and magnetism in four equations • This mathematical achievement demonstrated that electric and magnetic forces are really two aspects of the same ...
... • In the 1860s, the Scottish mathematician and physicist James Clerk Maxwell succeeded in describing all the basic properties of electricity and magnetism in four equations • This mathematical achievement demonstrated that electric and magnetic forces are really two aspects of the same ...
Volcanoes and Igneous Activity Earth
... remained in the same relative position to one another, except the seven “wanderers” which were: the sun, the moon, Mercury, Venus, Mars, Jupiter, and Saturn. ...
... remained in the same relative position to one another, except the seven “wanderers” which were: the sun, the moon, Mercury, Venus, Mars, Jupiter, and Saturn. ...
Lecture 17 Ptolemy on the Motion of the Earth
... If those objects too were carried around, fused, as it were, to the air, then they would never appear to have any motion either in advance or rearwards. [45] ...
... If those objects too were carried around, fused, as it were, to the air, then they would never appear to have any motion either in advance or rearwards. [45] ...
Study Guide for 1ST Astronomy Exam
... Study Guide for 1ST Astronomy Exam The successful will be able to… Unit 1: Our Planetary Neighborhood Write the planets in order of increasing distance from the Sun, Define a dwarf planet, Identify dwarf planets in the solar system, Using a ratio determine how much larger one object is compa ...
... Study Guide for 1ST Astronomy Exam The successful will be able to… Unit 1: Our Planetary Neighborhood Write the planets in order of increasing distance from the Sun, Define a dwarf planet, Identify dwarf planets in the solar system, Using a ratio determine how much larger one object is compa ...
Lecture 2 - Physics and Astronomy
... celestial object—what fraction of the sky that object seems to cover The angular diameter (or angular size) of the Moon is ½° or the Moon subtends an angle of ½°. ...
... celestial object—what fraction of the sky that object seems to cover The angular diameter (or angular size) of the Moon is ½° or the Moon subtends an angle of ½°. ...
X-RAY OBSERVATIONS OF SEYFERT GALAXIES The dawn of a …
... Observation of Earths shadow on the moon during lunar eclipses ...
... Observation of Earths shadow on the moon during lunar eclipses ...
History of astronomy - Part I.
... However, in a way, Ptolemy can be considered a plagiarist. He probably did not reobserve the 1000 brightest stars visible from Alexandra. He simple took the star catalogue of Hipparchus and precessed the coordinates for precession by adding the same angular value to the celestial longitudes of thos ...
... However, in a way, Ptolemy can be considered a plagiarist. He probably did not reobserve the 1000 brightest stars visible from Alexandra. He simple took the star catalogue of Hipparchus and precessed the coordinates for precession by adding the same angular value to the celestial longitudes of thos ...
Lecture 2 : Early Cosmology
... 2. The Earth's center is not the center of the universe. 3. The Earth and planets revolve around the Sun. 4. The distance from the Earth to the Sun is imperceptible compared with the distance to the stars. 5. The rotation of the Earth accounts for the apparent daily rotation of the stars. 6. Th ...
... 2. The Earth's center is not the center of the universe. 3. The Earth and planets revolve around the Sun. 4. The distance from the Earth to the Sun is imperceptible compared with the distance to the stars. 5. The rotation of the Earth accounts for the apparent daily rotation of the stars. 6. Th ...
Lecture 8 Ptolemy
... If those objects too were carried around, fused, as it were, to the air, then they would never appear to have any motion either in advance or rearwards. [45] ...
... If those objects too were carried around, fused, as it were, to the air, then they would never appear to have any motion either in advance or rearwards. [45] ...
29:52 Characteristics and Origins of the Solar System January 25
... The second of these lines is the ecliptic. The ecliptic is the projection of the Earth’s orbital plane on the celestial sphere. If we plotted up all the positions of the Sun against the background stars, it would trace out the ecliptic. Because of the 23.5 degree tilt of the Earth’s axis, the celest ...
... The second of these lines is the ecliptic. The ecliptic is the projection of the Earth’s orbital plane on the celestial sphere. If we plotted up all the positions of the Sun against the background stars, it would trace out the ecliptic. Because of the 23.5 degree tilt of the Earth’s axis, the celest ...
The History of Astronomy
... To avoid religious persecution he published his work “de revolutionibus orbium coelestium” posthumusly. ...
... To avoid religious persecution he published his work “de revolutionibus orbium coelestium” posthumusly. ...
Celestial Sphere, Celestial equator, N
... celestial sphere. Because of this, the stars and sun appear to trace circles on the celestial sphere – they appear to rise in the east and set in the west because of the rotation of the Earth about its axis. The stars and location of the Sun we see depends on the time of the year and on our position ...
... celestial sphere. Because of this, the stars and sun appear to trace circles on the celestial sphere – they appear to rise in the east and set in the west because of the rotation of the Earth about its axis. The stars and location of the Sun we see depends on the time of the year and on our position ...
The Heliocentric Model of the Solar System
... Hypothesis: The Sun is the center of the solar system. Only Moon orbits around Earth; Planets orbit around Sun. • Aristarchus of Samos was the first to propose it in ancient Greece (~300 BC) - but Aristotle’s model was the favorite one • He proposed that the Sun is the ‘center of life’ • Also th ...
... Hypothesis: The Sun is the center of the solar system. Only Moon orbits around Earth; Planets orbit around Sun. • Aristarchus of Samos was the first to propose it in ancient Greece (~300 BC) - but Aristotle’s model was the favorite one • He proposed that the Sun is the ‘center of life’ • Also th ...
Celestial spheres
The celestial spheres, or celestial orbs, were the fundamental entities of the cosmological models developed by Plato, Eudoxus, Aristotle, Ptolemy, Copernicus and others. In these celestial models the apparent motions of the fixed stars and the planets are accounted for by treating them as embedded in rotating spheres made of an aetherial, transparent fifth element (quintessence), like jewels set in orbs. Since it was believed that the fixed stars did not change their positions relative to one another, it was argued that they must be on the surface of a single starry sphere.In modern thought, the orbits of the planets are viewed as the paths of those planets through mostly empty space. Ancient and medieval thinkers, however, considered the celestial orbs to be thick spheres of rarefied matter nested one within the other, each one in complete contact with the sphere above it and the sphere below. When scholars applied Ptolemy's epicycles, they presumed that each planetary sphere was exactly thick enough to accommodate them. By combining this nested sphere model with astronomical observations, scholars calculated what became generally accepted values at the time for the distances to the Sun (about 4 million miles), to the other planets, and to the edge of the universe (about 73 million miles). The nested sphere model's distances to the Sun and planets differ significantly from modern measurements of the distances, and the size of the universe is now known to be inconceivably large and possibly infinite.Albert Van Helden has suggested that from about 1250 until the 17th century, virtually all educated Europeans were familiar with the Ptolemaic model of ""nesting spheres and the cosmic dimensions derived from it"". Even following the adoption of Copernicus's heliocentric model of the universe, new versions of the celestial sphere model were introduced, with the planetary spheres following this sequence from the central Sun: Mercury, Venus, Earth-Moon, Mars, Jupiter and Saturn.