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Jan 1, 1220
BC- 385 to BC-322 Aristotle
Aristotle was born in BC 385 in Greece and died in BC 322 in Greece. Aristotlew as a Greek philosopher and scientist who made a geocentric model of the solar system. -
Jan 2, 1220
AD- 90 to AD- 168 Ptolomy
Ptolomy was born in 90 AD in Egypt and died in 168 AD in Egypt. Ptolomy was known as a mathematician, astrologer, geographer, and an astronomer. Ptolomy believed that the solar system was geocentric and made a model of it. -
Feb 19, 1473
Nicolaus Copernicus
Copernicus was born on February 19th 1473 in Poland and died on May 24th 1543. Copernicus was a renaissance mathematician and astronomer. Copernicus did not believe in the geocentric models and made his own heliocentric model of the solar system. -
Feb 15, 1564
Galileo Galilei
Galileo Galilei was born on February 15th, 1564 in Pisa, Italy and died on January 8th, 1642 in Arcetri, Italy. Galileo was an Italian astronomer, physicist, engineer, philosopher, and mathematician who played a role in the scientific revolution in the Renaissance time period. Galileo did not believe in the geocentric theory, but thought the same has Copernicus: the heliocentric theory. -
The Geocentric and Heliocentric Theories
The geocentric theory was a theory that the sun and the other planets revolved around Earth, but this theory was proved wrong when Galileo and Copernicus lived. Ptolemy and Aristotle believed in this theory. The heliocentric theory was a theory that the planets revolved around the sun, and the solar system was sun-centered. Galileo and Copernicus believed in this theory. -
The Outer Planets
The Outer Planets of the solar system were discovered in the late 1700s. These planets are the planets farther away from the sun than the Earth, and the planets around Earth. The Outer Planets are, Uranus, Neptune, Saturn, and Jupiter. -
Artificial Satellites
Artificial Satellites are man made satellites sent into space to get information of the Earth and moon by orbiting them. The first U.S. artificial satellite made was the Explorer 1. -
NASA Rockets
The U.S. National Space Association called NASA was formed on July 29, 1958. NASA is still known today for it's many rockets trips to, so far, the moon. The rockets were made to reach planets in space and to explore the solar system. -
Orbital Missions
Orbital missions are missions to send an aircraft to orbit a planet and to get information from the planet. The first orbiter was the Friendship 7, this capsule orbited the Earth. -
Missions to the Moon
These missions were spacecrafts sent to the moon to explore and study the planet. The first US mission to the moon was Apollo 11. -
Mars Robotic Explorers
The Mars robotic explorers are little robots that NASA sends to Mars so we can collect information from the planet. We use robots since it's too dangerous to send a human to Mars now. The first U.S. robotic explorer was Maven, sent on November 18, 2013.
