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Now it’s time to learn about… FAMOUS SCIENTISTS • Nicholaus Copernicus • Galilei Galileo • Johannes Kepler • Isaac Newton Nicholaus Copernicus Helio- sun Centric- centered Heliocentric-sun centered solar system Postulating- assuming truth about Wait what is Heliocentric? (1473-1543) Polish astronomer and mathematician. Copernicus became interested in astronomy and published an early description of his "heliocentric" model of the solar system in Commentariolus (1512). In this model, the sun was actually not exactly the center of the solar system, but was slightly offset from the center. The idea that the Sun was the center of the solar system was not new (similar theories had been proposed by Aristarchus and Nicholas of Cusa), but Copernicus also worked out his system in full mathematical detail. Even though the mathematics in his description was not any simpler than Ptolemy's (an ancient Greek astronomer), it required fewer basic assumptions. By postulating only the rotation of the Earth, revolution about the sun, and tilt of Earth's rotational axis, Copernicus could explain the observed motion of the heavens. However, Copernicus retained circular orbits, which we know today to be wrong. Unfortunately, out of fear that his ideas might get him into trouble with the church, Copernicus delayed publication of them. not Postulating? Nicholaus Copernicus Helio- sun Centric- centered Heliocentric-sun centered solar system Postulating- assuming truth about (1473-1543) Polish astronomer and mathematician who, as a student, studied canon law, mathematics, and medicine at Cracow, Bologna, Rome, Padua, and Ferrara. Copernicus became interested in astronomy and published an early description of his "heliocentric" model of the solar system in Commentariolus (1512). In this model, the sun was actually not exactly the center of the solar system, but was slightly offset from the center. The idea that the Sun was the center of the solar system was not new (similar theories had been proposed by Aristarchus and Nicholas of Cusa), but Copernicus also worked out his system in full mathematical detail. Even though the mathematics in his description was not any simpler than Ptolemy's (an ancient Greek astronomer), it required fewer basic assumptions. By postulating only the rotation of the Earth, revolution about the sun, and tilt of Earth's rotational axis, Copernicus could explain the observed motion of the heavens. However, Copernicus retained circular orbits, which we know today to be wrong. Unfortunately, out of fear that his ideas might get him into trouble with the church, Copernicus delayed publication of them. Galileo Galilei (1564-1642) An Italian physicist and astronomer, was greatly remembered for some very important contributions to astronomy and physics. In 1609 he heard that in Holland a spy glass had been invented, and he was inspired to create the first telescope (a refracting telescope), which was as powerful as a modern day field glass. By December of the same year, he had built another telescope twenty times stronger than the first, which he was able to discovery craters on the moon with, stars in the milky way, and the four largest satellites of Jupiter. He had also observed the phases of Venus by this time. After his great discoveries, he mainly stuck to writing books. In 1613 he published a book about sunspots and in 1624 a book called Dialogue on the Tides. Although it is not for certain why Galileo became blind near the end of his life, many believe it was from his viewings of the sun through a telescope. Field Glass? 1. craters on the moon 2.Field stars in binoculars the glassmilky way 3. four largest satellites of Jupiter Satellites? 4. phases of Venus Satellite- Any object that revolves around another object in space. Johannes Kepler (1571-1630) Johannes Kepler, the son of a mercenary soldier and an innkeeper's daughter, was born prematurely just 2 days after Christmas 1571. Maestlin, Kepler’s mentor, was a proponent of the heliocentric model of the solar system and planets introduced by astronomer Nicolaus Copernicus. Johannes Kepler, too, accepted this theory immediately. Giving up his plan of becoming a clergyman, Kepler developed a complex hypothesis to explain the distance between the orbits of planets. (He, like so many before him, mistakenly believed these orbits were circular. Still, his early calculations matched the observational evidence within 5%. In his later work, he altered his thinking to believe that planetary orbits are elliptical.) Johannes Kepler next theorized that the sun emitted a constant force across the planes of a planet's orbit, which diminished with distance. He believed this force pushed the planets around their orbits. One of his major works was entitled Astronomia Nova (New Astronomy), which was published in 1609. Using the observations of his predecessor along with his own, he was able to calculate the orbit of the planet Mars. Forgetting all previous notions of circular planetary orbits, he theorized that the planets move in elliptic orbits with the sun at one focus. This was the first of Kepler's so-called Laws of Planetary Motion. The second law said Faster that theCloser closer a planet comes to a sun, the faster it moves. Proponent? HYPOTHESIS: The distance the in Proponentone between who argues orbits of of something planets. support Not circular THEORY: But The sun emitted a constant forceElliptical across the planes of a planet's orbit, which diminished with distance. He believed this force pushed the planets around their orbits. Isaac Newton Elucidationto make clear or plain (1642-1727) Certainly one of the greatest scientists who ever lived, Isaac Newton had a profound impact on astronomy, physics, and mathematics. Born prematurely and after his father’s death, Newton had a difficult childhood. His mother remarried when he was just three, and he was then sent to live with his grandparents. After his stepfather died, his mother brought him home to Woolsthorpe in Lincolnshire, where she wanted him to become a farmer. An uncle recognized his scholarly talents, however, and he eventually made it to Trinity College in Cambridge. Many of his great ideas came in 1665-66, when he spent time back at Woolsthorpe while Cambridge was closed because of the plague. Among his many achievements were the invention of the reflecting telescope—the basic design behind all large telescopes used today; the invention of a branch of mathematics known as calculus, a critical tool throughout science; the elucidation of the three laws of motion; and the development of the law of universal gravitation. Elucidation? reflecting telescope elucidation of the three laws of motion branch of mathematics known as calculus development of the law of universal gravitation Tools to study the universe • Telescopes • Probes • Satellites • Spacecraft Telescopes Electromagnetic radiation? A telescope is an astronomical tool which gathers and focuses electromagnetic radiation. Electromagnetic radiation Telescopes A telescope is an astronomical tool which gathers and focuses electromagnetic radiation. There are two types of visual telescopes: Reflecting telescopes What are the two types of telescopes boys and girls? Refracting telescopes Telescopes Uses of telescopes: • To look at stars from backyard. •To study galaxies far away. •To see features of the moon. •Can you name more? Probes Probe- a space probe is anUnmanned? unmanned space mission in which the spacecraft leaves Earth’s orbit Unmanned- not piloted by man but by robotics rover Probes Uses of Probes: • Closer inspection of other planets. • Taking samples of soil from other planets. • Investigate asteroid and comet composition. • Can you think of anymore? Satellites • Satellites- Any object that revolves Revolves?around another object in space. Why is the Revolvemoon a to orbit a central point satellite? Because the moon revolves around the Earth silly! Hubble Space Telescope Satellites • Satellites- Any object that revolves around another object in space. Why is the moon a satellite? Because the moon revolves around the Earth silly! Satellites Uses of Satellites: • Study the features of the Earth and Moon. •Weather, communication, remote sensing, & navigation. •Astronomy satellites •Others? Spacecraft A spacecraft is a vehicle that travels through space. (Spacecraft include robotic or unmanned space probes as well as manned vehicles. The term is sometimes also used to describe artificial satellites, which have similar design criteria.) Spacecraft Uses of Spacecraft: • All uses listed above • Bring man into space to … – Study effects space has on man or other living things from Earth – Fix manmade satellites in space – Go to the moon – Maybe go to Mars??? Rockets vs. Shuttles Rockets- A rocket is a vehicle, missile or aircraft which obtains thrust by the reaction to the ejection of fast moving exhaust gas from within a rocket engine. Multistage Rocket Rockets vs. Shuttles Shuttles land so that theyBut a space shuttle still may be reused in the needs a rocket to get it future! into space! The Shuttle is the first orbital spacecraft designed for partial reusability.