| Question |
 |
|
| Answer |
|
|
| Kepler's 1st law of Planetary Motion |
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 |
| Rotation |
The spinning of an object around its axis |
| Revolution |
The orbital motion of one object around another |
Ch.18 LTI-MA 509
