ASTRON🌍MY

ARISTOTLE

• 384 - 322 B.C.E
• Thought the earth was the center of all things
• Placed models of the stars, moon, planets, and sun surrounding the earth
• Thought the relative location of stars would change as earth moves

Aristotle's Model

ARISTARCHUS

• 310 - 230 B.C.E
• Proposed a heliocentric model of the solar system
• Attempted to measure the relative distance to the moon and sun
• Thus doing, it was a major contribution to science
• His ratio of distance was way to small but was very important

Aristarchus' Model

PTOLEMY

• 100 - 170 C.E
• Wrote a book called Almagest
• Book was based on observations of the planets
• Built a model used for the next 14 centuries
• Model had planets built on circles growing larger

Ptolemy Model

COPERNICUS

• 1473 - 1543
• Thought Ptolemy's model was to complicated
• Developed the first detailed heliocentric model

COPERNICUS' Model

JOHANNES KEPLER

• 1571 - 1630
• Came up with law of planetary motion

LAW OF PLANETARY MOTION

GALILEO GALILEI

• 1564 - 1642
• Modified the telescope
• Saw sunspots looking through his telescope
• Found the moons of jupiter

GALILEO'S TELESCOPE

ISAAC NEWTON

• 1643 - 1727
• Made first reflecting telescope

ISAAC NEWTON'S TELESCOPE

EDWIN HUBBLE

• 1889 - 1953
• Discovered the cosmos
• Made the Hubble Space Telescope

THE COSMOS

GEOCENTRIC MODEL

• description of the cosmos where Earth continued...
• is at the orbital center of all celestial bodies

HELIOCENTRIC MODEL

• a theory that places the Sun as the center continued...
• of the universe, and the planets orbiting around it

KEPLER

• Planets orbit in an ellipses amd have the sun in the center
• Planets sweep out equal areas at equal times
• There is a mathematical relationship to a planets period conituned...
• Of revolution and its distance from the sun

ISAAC NEWTON

• Member of the "gravity hall of fame"
• Used Kepler's Laws and math to describe how gravity behaved
• Force=Mass x Acceleration

LAW OF UNIVERSAL GRAVITATION

• The force of gravity:
• Increases as the masses of the object increases
• Decreases as the distance between the object increases
• Centripetal Force=planet orbits