Nicolaus Copernicus
From Poland. Copernicus concluded that Earth is a planet. He proposed a model of the solar system with the sun at the center.
Tyco Brahe
Born a Danish nobility. Brahe's observations, especially of Mars, were far more precise than any made previously. Built a instruments, such as the angle measuring device. To measure the locations of heavenly bodies.
Johannes Kepler
Kepler was Brahe's able assistant. Kepler kept most of Brahe's observations and put them to exceptional use. Kepler discovered 3 laws of planetary motion.
Kepler Laws 1
The path of each planet around the sun is an ellispse, with the sun at one focus. The other focus is symmetrically locted at the opporsite end of the ellispse.
Kepler Laws 2
Each planet revloves so that an imaginary line connecting it to the sun sweeps over equal areas in equal time intervals. If a planet is to sweep equal areas in teh same amount of time, it must travel more rapidly when it is nearer the sun and more slowly
Kepler Laws 3
The square of the length of time it takes a planet to orbit the sun (Orbital period is proportional to the cube of its mean distance to the sun. Orbital period of revolution is measured in Earth years. Planet's distance to the sun is expressed in astronom
Galileo Galilei
Most immportant contributions were his descriptions of the behavior of moving objects. Galileo used lens made by a Dutch lens maker to constructed his own telescope and used it to study the sky.
Galileo Galilei Discoveries
1. Four moons orbiting Jupiter. Proving that earth was not the center of motion in the universe.
2. Planets are cricular disks, not just points of light, as was previously thought. Planets were not stars.
3. Venus has phases just like the moon. So Venus o
Sir Isaac Newton
Newton described a force that holds the moon in orbit around Earth. Although others had theorized the existence of such a force, Newton was the first to formulate and test the law of universal gravitation.
Inertia
Proposed that a moving object will continue to move at a constant speed and in a straight line.
Ptolemaic model of the solar system
The planets moving in circular orbits around a motionless Earth. The precision with which his theory was able to predict the motion of the planets allowed it to go unchallenged
Aristotle
Greek Philosopher. Earth is round because it always casts a curved shadow on the moon when it passes between the sun and the moon.
Eratosthenes
Successful attempt to establish the size of Earth is credited.
Genocentric Model
The moon, sun, and the known planets Mercury, Venus, Mars, and Jupiter go around Earth.
Heliocentric Model
Earth and the other planets orbit the sun.
Rotation
Is the turning, or spinning, of a body on its axis. Main results of Earth's rotation are day and night. Earth's rotation has become a standard method of measuring time. Each rotation of the earth around its axis equals about 24 hours.
Revolution
Is the motion of a body, such as a planet or moon, along its orbit around some point in space. Earth revolves around the sun in an elliptical orbit at an average speed of 107,000 kilometers per hour.
Precession
A slow movement of Earth, is the motion of Earth's axis as it tracces out a circle on the sky.
Solar Eclipse
Earth and the sun, it casts a dark shadow on Earth and produces a solar eclipse This situation occurs during new moon phases.
Lunar Eclipse
The moon is eclipsed when it moves within Earth's shadow. This situation occurs during fullmoon phases.
The Lunar Surface
Craters- which are round depressions in the surface of the moon.
Highlands-Most of the lunar surface is made up of densely pitted, light-colored areas known as highlands. Highlands cover most of the surface of the far side of the moon.
Maria- A dark, rela
Phases of the moon
On a monthly basis we observe the pahses of the moon as a change in the amount of the moon that apperas lit.
Crescent Phase
About 2 days after a new moon a thin sliver appears low in the western sky just after sunset.
First-quarter phase
The following week the lighted portion of the moon visible from Earth increases (waxing) to a half circle. and can be seen from about noon to midnight.
Full-moon phase
In another week the complete disk can be seen rising in the east as the sun is sinking in the west. During the next 2 weeks the percentage of the moon the can be seen steadily declines (warning).
New-moon phase
(warning) the cycle soon begins again with the reappearance of the crescent moon.
Perigee
When the moon is closest to the Earth.
Apogee
The moon is farthest from Earth.
Perihelion
At Perihelion Earth is closest to the sun. About 147 million kilometers away. Perihelion occurs about January 3 each year. Earth is closest to the sun in January.
Aphelion
Earth is farthest from the sun-about 152 million kilometers away. Aphelion occurs about July 4. Earth is farthest from the sun in July
Synodic Month
The time interval required for the moon to complete a full cycle of phases is 29.5 days or one synodic month.
Sidereal Month
The true period of the moon's revolution around Earth, however is only 27.3 days and is known as the sidereal month.
Solar Day
Time interval from one noon to the next, which is on average, about 24 hours. Noon is when the sun has reached it highest point in the sky for the day.
Sidereal Day
The time it takes the Earth to make one complete rotation (360 degrees) with respect to a star other than our sun. Sidereal day is measured by the time required for a star to reappear at the identical poisiton in the sky where it was observed the day befo
Equinoxes
when a day and night are of equal length in both hemispheres
Solstices
each of these days, when the sun is the farthest north or south of the equator