History of Astronomy and A Quick Look at Our Solar System

Warm Up 8/31/15 What is the result of the moon’s time of rotation and time of revolution being the same?

Early Astronomers Aristotle ( BC) was one of the first to concluded that the earth was round. Eratosthenes ( BC) observed by looking at the angle of shadows between two cities that the earth was 24,482 miles in diameter. He was WRONG The earth is 24,901 miles in diameter. Idiot Aristotle ( BC) was one of the first to concluded that the earth was round. Eratosthenes ( BC) observed by looking at the angle of shadows between two cities that the earth was 24,482 miles in diameter. He was WRONG The earth is 24,901 miles in diameter. Idiot

More Early Astronomers Hipparchus (2 nd Century BC) determined the location of almost 850 stars. Measured the length of the year to within minutes of the modern year. Hipparchus (2 nd Century BC) determined the location of almost 850 stars. Measured the length of the year to within minutes of the modern year.

Two Views of the solar system Geocentric ModelGeocentric Model: The model that the sun, moon, and known planets (Mercury, Venus, Mars, and Jupiter) orbit the earth. Heliocentric ModelHeliocentric Model: The Earth and other planets orbit the sun. Geocentric Model: The model that the sun, moon, and known planets (Mercury, Venus, Mars, and Jupiter) orbit the earth. Heliocentric Model: The Earth and other planets orbit the sun.

Geocentric Model

Heliocentric model

ON THE SHOULDERS OF GIANTS 5 People that changed our world. Nicolaus Copernicus Johannes Kepler Galileo Galilei Sir Isaac Newton Albert Einstein 5 People that changed our world. Nicolaus Copernicus Johannes Kepler Galileo Galilei Sir Isaac Newton Albert Einstein

On the Revolutions Nicolaus Copernicus ( ) On the Revolutions (1543) Said the Earth was a planet. He made the heliocentric model His book was secretly given to friends and was not published widely until the 19 th century. Said the Earth was a planet. He made the heliocentric model His book was secretly given to friends and was not published widely until the 19 th century. Copernicus was a mathematician, astronomer, physician, classical scholar, translator, Catholic cleric, jurist, governor, military leader, diplomat and economist.

Copernicus proposed that the planets have the Sun as the fixed point to which their motions are to be referred; that the Earth is a planet which, besides orbiting the Sun annually, also turns once daily on its own axis; and that very slow, long-term changes in the direction of this axis account for the precession of the equinoxes.

Johannes Kepler ( ) Discovered the 3 laws of planetary motion: The Path of each planet is an ellipse Planets travel faster the closer they get to the sun and slower the further away they are from the sun. The length of time it takes a planet to revolve around the sun is proportional to it’s distance. Discovered the 3 laws of planetary motion: The Path of each planet is an ellipse Planets travel faster the closer they get to the sun and slower the further away they are from the sun. The length of time it takes a planet to revolve around the sun is proportional to it’s distance.

Had to defend his mother for witchcraft. Trial was thrown out because of authorities failure to use correct procedures for torture. Had to defend his mother for witchcraft. Trial was thrown out because of authorities failure to use correct procedures for torture.

Galileo Galilei (1564 – 1642) Observed the planets using a telescope. Brought back the Heliocentric Model. Observed the planets using a telescope. Brought back the Heliocentric Model.

Galileo Galilei (1564 – 1642) Discovered Jupiter had 4 moons Discovered that planets were circular and not just points of light Discovered Venus has phases like the moon. Discovered the moons surface was not smooth. Discovered sun spots. Discovered Jupiter had 4 moons Discovered that planets were circular and not just points of light Discovered Venus has phases like the moon. Discovered the moons surface was not smooth. Discovered sun spots.

Galileo Galilei (1564 – 1642) Tried for Heresy

“… I, after having been admonished by his HOLY Office entirely to abandon the false opinion that the sun was the centre of the universe and immoveable, and that the earth was not the centre of the same and that it moved,….I have been judged vehemently suspected of heresy, that is, of having held and believed that the sun is the centre of the universe and immoveable, and that the earth is not the centre of the same, and THAT IT DOESN’T MOVE…” Galilei as part of his confession in 1616

“Eppur si muove” “And yet, it moves” He went blind, and died on January 8, 1642 “And yet, it moves” He went blind, and died on January 8, 1642

The Catholic Church Apologized to Galileo in 1992 Oops our bad

Philosophiae Naturalis Principia Mathematica Isaac Newton ( ) Philosophiae Naturalis Principia Mathematica Wrote the book on the laws of gravity. And the 3 laws of motion 1. A body at rest will remain at rest unless acted on by a force. 2. F=ma 3. For every action there is an equal and opposite reaction. Wrote the book on the laws of gravity. And the 3 laws of motion 1. A body at rest will remain at rest unless acted on by a force. 2. F=ma 3. For every action there is an equal and opposite reaction.

Newton also stated that gravity is universal In normal words…. Gravity is everywhere In normal words…. Gravity is everywhere

Albert Einstein (1879 – 1955) “Greatest year in Physics” 1905 Einstein published the Theory of Relativity. Stating the speed limit of the universe is 186,000 miles per second (the speed of light) Won the Nobel Prize in physics for his work in electrodynamics. Also invented the atomic bomb “Greatest year in Physics” 1905 Einstein published the Theory of Relativity. Stating the speed limit of the universe is 186,000 miles per second (the speed of light) Won the Nobel Prize in physics for his work in electrodynamics. Also invented the atomic bomb

Einstein Quotes "Gravity cannot be held responsible for people falling in love.“"Gravity cannot be held responsible for people falling in love.“ "When you sit with a nice girl for two hours, it seems like two minutes. When you sit on a hot stove for two minutes, it seems like two hours that's relativity.""When you sit with a nice girl for two hours, it seems like two minutes. When you sit on a hot stove for two minutes, it seems like two hours that's relativity." If we knew what it was we were doing, it would not be called research, would it?"If we knew what it was we were doing, it would not be called research, would it?" "I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones"I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones." "Gravity cannot be held responsible for people falling in love.“"Gravity cannot be held responsible for people falling in love.“ "When you sit with a nice girl for two hours, it seems like two minutes. When you sit on a hot stove for two minutes, it seems like two hours that's relativity.""When you sit with a nice girl for two hours, it seems like two minutes. When you sit on a hot stove for two minutes, it seems like two hours that's relativity." If we knew what it was we were doing, it would not be called research, would it?"If we knew what it was we were doing, it would not be called research, would it?" "I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones"I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones."

Motions of Earth Two main motions of the Earth: Rotation (spinning of a body on it’s axis) and Revolution (motion of a body along a path around some point in space). Precession is slight movement of the Earth’s axis Two main motions of the Earth: Rotation (spinning of a body on it’s axis) and Revolution (motion of a body along a path around some point in space). Precession is slight movement of the Earth’s axis

Motion cont. At perihelion, Earth is closest to the sun. At aphelion, Earth is farthest from the sun. At perihelion, Earth is closest to the sun. At aphelion, Earth is farthest from the sun.

Earth’s Axis Earth’s axis of rotation is ~ 23.5 degrees. This results in ________?

The Moon Gravitational changes caused by the moon result in ________? More about tides coming soon!!! Gravitational changes caused by the moon result in ________? More about tides coming soon!!!