The document discusses the Earth's place in the universe. It describes the geocentric and heliocentric models of the solar system, with the geocentric model proposed by Ptolemy putting Earth at the center, and the heliocentric model proposed by Copernicus putting the Sun at the center. It discusses Galileo Galilei's use of the telescope to observe celestial bodies and how this supported the heliocentric model, getting him into trouble with the Catholic Church. The document also provides brief descriptions of galaxies, the Milky Way galaxy, the Solar System and its planets, and motions of Earth that result in day/night and seasons.

1. TheEarthin theUniverse

2. Sinceancient times, themovement of celestial bodies has attractedtheinterestof humanbeings.?

3. There are twotheoriesormodelstoexplainoursituation in theUniverse:Thegeocentricmodel

4. TheheliocentricmodelThegeocentricmodelPtolemy was a Greek astronomer who lived between 85- 165 A D. He was one of the first people who proposed a theory about the movement of heavenly bodies. This theory stated that the Earth was at the center of the Universe and all celestial bodies revolved around it.

5. TheheliocentricmodelNicholas Copernicus was a Polish astronomer who lived between 1474-1543.Before his time, people believed in the Ptolemy model. He changed this belief when he introduced the heliocentric theory. He claimed that all planets including the Earth, moved around the sun.

6. Galileo GalileiGalileo Galilei was an Italian astronomer. He was born at the end of the sixteenth century. He was the first person to use a telescope to look at the sky. This invention was a major step forward in the knowledge of the cosmos. His defense of the heliocentric theory offended the Roman Catholic Church and this almost cost his life. He was sentenced by the Inquisition to house arrest for the rest of his life.

7. Galaxies are hugeclusters of stars, interstellar gas and dust. Theymaycontainbillionsortrillions of starsand severalplanetarysystems.Whatis a galaxy?

8. Ourgalaxy: TheMilkyWayTheuniversecontainsbillions of galaxies. TheMilkyWayisthegalaxyin whichourSolar Systemislocatedtogetherwithotherstars and planets.TheMilkyWay has a spiralshape and has severalarms.Welive at thispoint, itiscalledOrionArm

9. The Solar SystemA mediumstar: TheSunThe Solar Systemconsists of A group of 8 planets, somedwarfplanets and 64 satellites.

10. A belt of asteroidsmostlybetweenMars and Jupiter

11. CometsAsteroids are rockyfragments of variable size.Comets are bodies of rock, ice and dustSatellites are bodiesthatrevolvearoundtheplanets.

12. Planets in our Solar SystemTheSunJupiterUranusTheEarthMercuryNeptuneMarsSaturnVenus

13. EarthMovementsPlanetshavetwomovements: a traslationaroundthesun and rotationarounditsaxis.TraslationRotation

14. DayornightTherotationalmotion of theEarth causes whatwecall “night” and “day”Earthrotatesfromwesttoeastdaynight

15. SeasonsSeasons are a consequence of translationalmotion and thetilt of Earth´s axisInviernoLos rayos son más perpendiculares a la superficie terrestre