History of AstronomyHistory of Astronomyandand

A Quick Look at Our A Quick Look at Our Solar SystemSolar System

History of AstronomyHistory of Astronomyandand

A Quick Look at Our A Quick Look at Our Solar SystemSolar System

Warm Up 8/31/15Warm Up 8/31/15

• What is the result of the moon’s time of rotation and time of revolution being the same?

• What is the result of the moon’s time of rotation and time of revolution being the same?

Early AstronomersEarly Astronomers

• Aristotle (384-322 BC) was one of the first to concluded that the earth was round.

• Eratosthenes (276-194 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 (384-322 BC) was one of the first to concluded that the earth was round.

• Eratosthenes (276-194 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 AstronomersMore Early Astronomers

• Hipparchus (2nd Century BC) determined the location of almost 850 stars.

• Measured the length of the year to within minutes of the modern year.

• Hipparchus (2nd 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 systemTwo 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 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 ModelGeocentric Model

Heliocentric modelHeliocentric model

ON THE SHOULDERS OF GIANTSON 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

Nicolaus Copernicus (1473-1543)

On the RevolutionsOn the Revolutions (1543)

Nicolaus Copernicus (1473-1543)

On the RevolutionsOn 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 19th 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 19th 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.

• 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 (1571-1630)

Johannes Kepler (1571-1630)

• 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)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)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)Galileo Galilei (1564 – 1642)

• Tried for Heresy • Tried for Heresy

“… “… I, after having been admonished by his HOLY Office entirely to abandon 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, 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 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 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 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…” the earth is not the centre of the same, and THAT IT DOESN’T MOVE…”

Galilei as part of his confession in 1616Galilei as part of his confession in 1616

“Eppur si muove”“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 The Catholic Church Apologized to Galileo in Apologized to Galileo in

19921992

The Catholic Church The Catholic Church Apologized to Galileo in Apologized to Galileo in

19921992

Oops our badOops our bad

Isaac Newton (1642-1727)Philosophiae Naturalis Principia Philosophiae Naturalis Principia

MathematicaMathematica

Isaac Newton (1642-1727)Philosophiae Naturalis Principia Philosophiae Naturalis Principia

MathematicaMathematica• 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

Newton also stated that gravity is universal

• In normal words….

• Gravity is everywhere

• In normal words….

• Gravity is everywhere

Albert Einstein (1879 – 1955)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 QuotesEinstein 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 "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 minutes. When you sit on a hot stove for two minutes, it seems like two hours that's relativity." two hours that's relativity."

• If we knew what it was we were doing, it would not be called If we knew what it was we were doing, it would not be called research, would it?"research, would it?"

• "I know not with what weapons World War III will be fought, but "I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stonesWorld 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 "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 minutes. When you sit on a hot stove for two minutes, it seems like two hours that's relativity." two hours that's relativity."

• If we knew what it was we were doing, it would not be called If we knew what it was we were doing, it would not be called research, would it?"research, would it?"

• "I know not with what weapons World War III will be fought, but "I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stonesWorld War IV will be fought with sticks and stones."

Motions of EarthMotions 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.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 AxisEarth’s Axis

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

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

The MoonThe 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!!!