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Ptolemy's first known observation was March 26, 127. Ptolemy wrote a book called Almagest, and he created a geocentric model that was used for 14 centuries..
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Copernicus was born on February 19, 1473. He used "a wheels-on-wheels" method in his detaile heliocentric model. A heliocentric model is a model of the solar system with the sun in the center. Copernicus's model was thought of as the first step towards a more modern model.
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Galileo was born in 1564. He used scientific methods in his work similar to the ones we use today. Galileo made major improvements to the telescope which helped him to observe Jupiter's moons, reallize that Earth was not the only planet that could be orbited, and discover that Venus has phases similar to Earth's moon.
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The Soviet Union launched the first artificial satellite on this day.
An artificial satellite is a machine built by humans that orits a planet. -
Yuri A. Gagarin was the first cosmonaut to orbit Earth.
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In 1962 the Telstar satellite was joined, by technicians, to a Delta rocket. The Telstar satellite was the first satellite to send out TV signals.
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The Mariner 2 reached 35,000 km away from Venus in 1962, and it returned with data from the planet.
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The first mission to the moon was in 1969. Apollo 11 was the rocket that took the astronauts to the moon.
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The first space station was launched in 1971. The space station had an orbital mission. This means it was supposed to orbit Earth.
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In 1972 Pioneer 10 was the first space probe to make observations of Jupiter and travel through the astroid belt.
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The last mission to the moon was in 1972. The rocket that took the astronauts to the moon was Apollo 17.
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In 1976 Viking 2 landed on Mars. It took over 16,000 pictures until it stopped working in 1978. Viking 2 was a Mars robotic explorer. It was a robot, a type of machine, that landed on the surface of Mars and traveled over the land taking pictures and gathering data.
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In 1981 space shuttle flights began to occur. They retrieved satelltes that were orbiting Earth.
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In 1989 Galileo was launched. It's purpose was to study Jupiter. It passed by Jupiter in 1995. Jupiter is one out of the four outer planets. Jupiter, Saturn, Uranus, and Neptune are all outer planets also know as gas giants. These gas giants are large planets that are made out of many gasses. These planets are very cold becasue they are so far from the sun.
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In 1996 the Mars Sojourner analyzed the surface of Mars whith an x-ray spectrometer. The Mars Sojourner landed on Mars in 1997.
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In 1997 the Cassini-Huygens space probe was launched. It was created to study saturn and it's moons.
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The Mars Exploration and Opportunity landed on Mars and explored opposite sides of the Martian surface. The Mars Exploration Rovers Spirit landed on Mars on January 4, 2004. The Opportunity landed on Mars on January 25, 2004.
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The Deep Impact released an impactor into Comet Temple 1 to study it's interior's composition.
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In 2009 NOAA, the National Oceanic Atmospheric Administration, got ready to launch a polar orbiter weather satellite.
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Aristotle was born 385 B.C.E., the month and day is not clear but April 16 is one estimate at his birth date. Aristotle proposed a geocentric model of the Earth, a model of the solar system with Earth as the center. He thought the stars moved with Earth as it moved, becasue he couldn't identify parallax, the apparent movement of an object.
