The orbit of each planet about the Sun is an ellipse with the Sun at one focus
Newton
Built the first reflecting telescope (1668)
Copernicus
Published heliocentric theory of the Universe (1543)
Galileo
Used telescope for astronomical purposes and discovers 4 Jovian moons, Moon's craters, and Milky Way Galaxy (1609)
Ptolemy
Suggested geocentric theory of the universe in work Mathematike Syntaxis (140 BC)
Brahe
Discovered a supernova in the constellation Cassiopeia (1572)
Aristarchus
Suggested the Earth revolves around the Sun. He provided the first estimate of Earth-Sun distance (280 BC)
Eratosthenes
Measured the circumference of the Earth with surprising accuracy (240 BC)
Hipparchus
Developed first accurate star map and star catalogue with over 850 bright stars (130 BC)
First Solar/Lunar calendars
2000 BC in Egypt and Mesopotamia
Julian Calendar
Purely solar calendar implemented in the Roman Empire (45 BC)
Hans Lippershey
Spectacle maker invents telescope (1608)
Kepler
Created the 3 laws of Planetary Motion (1609 - 1619)
Kepler's 2nd law of Planetary Motion
As a planet moves around its orbit, it sweeps out equal areas in equal times. This tells us that a planet moves faster when it is closer to the Sun (near perihelion) than when it is farther from the Sun (near aphelion) in its orbit.
Newton's Laws
3 Laws of Motion and the Universal law of gravitation
Newton's Laws of Motion
1) In the absence of a net force, an object moves with constant velocity
2) a net force affects an object's motion. Force = rate of change in momentum or force = mass X acceleration
3) For any force, there is always an equal and opposite reactive force.
Newton's Universal law of Gravitation
The force of gravity (Fg) between two objects given by the formula Fg = G(M1M2/d2)
Drake Equation
Lays out the factors that play a role in determining the number of communicating civilizations in our galaxy.
Circles within circles
Ancient Greek theory that the earth was the center of the Universe and all planets moved in perfect circles around Earth.
Heliocentric
Belief that the sun is the center of the Universe
Geocentric
Ancient belief that the Earth is the center of the Universe
Conservation of energy
Energy (including mass-energy) can be neither created nor destroyed, but can only change from one form to another
Conservation of momentum
In the absence of net force, the total momentum of a system remains constant
Conservation of angular momentum
in the absence of net torque (twisting force), the total angular moment of a system remains constant
Azimuth
Direction around the horizon from due north, measured clockwise in degrees
Astronomy
The study of the Universe and movement of the planets
Astrology
The study of the movement of the stars and how their alignment affects people's lives
Stars in Milky Way
100 Billion
Stars in the entire Universe
100 Billion X 100 Billion = 10,000,000,000,000,000,000,000 or 10^22
Speed of Light
300,000 km per sec
Size of the Earth
Earth = tip of a ballpoint pen
Sun = size of a grapefruit
Distance to the Sun
1 AU or 150,000,000 km
Distance to the moon
4 days from the earth
Age of the Solar System
13.7 Billion Years
Ecliptic
Apparent movement of the sun and stars across the sky
Zenith
90 degrees above the horizon (straight up)
Azimuth
left to right direction
Mass
amount of particles in a given space
Acceleration due to gravity
The acceleration of a falling object which is designated by g = 9.8 m/s squared
Energy
what makes matter move; kinetic, potential, radiative
Astronimical Units (AU)
The average distance (semimajor axis) of the Earth from the Sun which is about 150 million km
Light Year
Distance light travels in one year which is 9.45 trillion km (9.46 x 10^14) which = 300,000 km/sec
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