-
150
Ptolemy
Ptolemy is the creator of the geocentric belief, which puts Earth at the center of the universe. -
Period: Feb 19, 1473 to May 24, 1543
Nicolaus Copernicus
Nicolaus Copernicus was the first person to develop a coprehensive heliocentric model of the solar system. Heliocentric means revolving around the sun. -
Period: Feb 15, 1564 to
Galileo Galilei
Galileo Galilei supported Nicolaus Copernicus' heliocentric model. He publicly supported Copernicus at a time where a geocentric view was far more common. -
Period: Dec 27, 1571 to
Johannes Kepler
- The orbit of every planet is an ellipse with the Sun at one of the two focuses.
- A line joining a planet and the Sun sweeps out equal areas during equal intervals of tim.
- The square of the orbital period of a planet is directly proportional to the cube of the semi-major axis of its orbit.
-
Period: to
Sir Isaac Newton
Sir Isaac Newton built the first reflecting telescope. He also discovered that the planets orbit the sun because of the gravitational pull. -
Uranus
Discovered by William Herschel, Uranus is the third largest planet in our solar system. It is a gas giant with a 51,200 km diameter. At its aphelion it is 3 billion km away from the sun. -
Ceres
Ceres is the biggest asteroid in our solar system The difference between asteroids and comets is that asteroids are made of metal and rock while comets are made of rock, ice, and dust. The difference between a comet and a meteoroid is that a meteoroid orbits the sun while a comet does not. -
Neptune
Neptune is a gas giant with a diameter of 49,500 km. At its aphelion it is over 4.5 billion km away from the sun. -
Hoba
Hoba is the largest meteor ever discovered. It was discovered when a farmer was plowing a field and his plow stopped. it weighs 66 tons. The difference between a meteor, a comet, and an asteroid is that a meteor orbits the sun. -
Pluto Discovered
Pluto differs from the othe outer planets because it is not a true planet, it is a dwarf planet. It is a dwarf planet because it is far smaller than all the other planets -
Halley's Comet - 239 B.C.
Halley's comet was the first comet ever discovered, and is visible on Earth every 75 to 76 years. -
Pluto named a dwarf planet
Pluto, which was before thought of as a regular planet, is designated a dwarf planet -
Gas Giant
Gas giants are planets that are not composed of rock or other solid materials. The gas giants in our solar system are Jupiter, Saturn, Uranus, and Neptune. -
Terrestrial Planets
A terrestrial planet is a planet that is primarily composed of silicate rocks and metals. Mercury, Mars, Venus, and Earth are Terrestrial planets. -
Mercury
Mercury is the smallest planet not including Pluto. It is a terrestrial planet. Its diameter is 4,878 km and at the point in its orbit farthest away from the sun it is about 70 million km from the sun. -
Venus
Venus is the third smallest planet excluding Pluto. Venus is a gas giant with a diameter of 12,104 km. At its point in its orbit farthest away from the Sun it is 109 million km away. -
Saturn
Saturn, a gas giant, is the second biggest planet in our Solar System. It has a diameter of 120,540, and at its aphelion it is 1.5 billion km away from the sun. -
Mars
Mars is the second smallest planet excluding Pluto, a terrestrial planet with a 6,794 km diameter. At its point farthest away from the sun it is 249 million km away. -
Earth
Earth is a terrestrial planet with a diameter of 12,756 km. At the point farthest away from sun (the aphelion) it is nearly 153 million km away from the sun. -
Jupiter
Jupiter, a gas giant, is the biggest planet in our solar system. It has a diameter of 142,800 km, which is over 11 times larger than Earth's. At its aphelion it is over 815 million km away form the sun.
