Studying Science

Studying ScienceChapter 1Astronomy: The Original ScienceSection 1 VocabularyAstronomyYearMonthDayIntroductionSeasonal cycles of the stars, planets, and the moon to mark the passage of timeBest times of year to plant and harvest cropsObservatoriesStudy of the universeLed to first calendars

Our Modern CalendarBased on the observations of bodies in our solar systemTime required for the Earth to orbit once around the sunRoughly the amount of time required for the moon to orbit around the EarthThe time required for the Earth to rotate once on its axis

Whos Who of Early AstronomyHelped people understand their place in the universe Oral historiesDiscovered with their eyes and mindsStars edge of the universePtolemy and Copernicus

Ptolemy: An Earth-Centered Universe140 CE book that combined all the ancient knowledge of astronomy that he could findPtolemaic theoryEarth was at the center of the universe and the other planets revolved around Earth (geocentric)

Copernicus: A Sun Centered Universe1543-New theory that will eventually revolutionize astronomySun is at the center of the universe (heliocentric)Did not replace Plotemaic theory immediatelyCoperinican Revolution

Tycho Brahe: A Wealth of DataLate-1500s-several large tools to make the most detailed astronomical observationsDifferent geocentric modelSun and moon revolve around EarthPlanets move around the sun

Johannes Kepler: Laws of Planetary MotionBrahes assistant continued his workDid not agree with his theory1609-all of the planets revolve around the sun in elliptical orbits and the sun is not in the exact center of the orbits.3 laws of planetary motion

Galileo: Turning a Telescope to the Sky1609-one of the first people to use a telescope to observe objects in spaceCraters and mountains on the Earths moonFour of Jupiters MoonsSunspots on the SunPhases of VenusNot Wandering Stars but physical bodies

Isaac Newton: The Laws of Gravity1687-all objects in the universe attract each other through gravitational forceForce of gravity depends on the mass of the objects and the distance between themExplained why we travel around the sun

Modern AstronomyEdwin Hubble: Beyond the Edge of the Milky WayTwo MilestonesInvention of the TelescopeDescription of GravityBefore the 1920s thought the Milky Way (our galaxy) included every object in space1924-proved that other galaxies existed beyond our galaxyComputers help process data and control the movement of telescopes

TelescopesSection 2 VocabularyTelescopeRefracting TelescopeReflecting TelescopeElectromagnetic Spectrum

IntroductionStandard toolProfessional astronomersAmateur stargazersAn instrument that gathers electromagnetic radiation from objects in space and concentrates it better for observation

Optical TelescopesMost commonStudy visible light from objects in the universeHelps to see so much more in the skyCollects visible light and focuses it to a focal point for closer observationThe point where the rays of light that pass through the lens or that reflect from a mirror coverage

Optical TelescopesSimplest telescope has two lens1. Objective Lens- collects light and forms an image at the back of the telescopesThe bigger the lensThe more light can gather2. Second lens-located in the eyepiece of the telescopeMagnifies the image produced by the objective lens

Refracting Vs. ReflectingRefracting TelescopesReflecting TelescopesTelescopes that use lenses to gather and focus lightObjective lens that bends light that passes through it and focuses the light to be magnified by an eyepieceTwo DisadvantagesCannot be perfectly focusedSize is limited due to the objective lens

Telescope that uses a curved mirror to gather and focus lightLight enters the telescope and is reflected from a large curved mirror to a flat mirrorFlat mirror focuses the image and reflects the light to be magnifiedAdvantagesMirrors can be very largePrevents light from entering the glassFocus all colors of light to the same focal pointRefracting Vs. ReflectingRefracting TelescopesReflecting Telescopes

Very Large Reflecting TelescopesSeveral mirrors work together to collect light and focus it in the same areaHawaiiTwin telescopes36 hexagonal mirrors that work togetherLinking several mirrors-more light to be collected and focused in one spot

Optical Telescopes and the AtmosphereLight gathered by telescopes on the Earth is affected by the atmosphereAtmosphereCauses starlight to shimmer and blur due to the motion of the air above the telescopesLight pollution from large cities can make the sky look brightPlaces for telescopesDry areas Mountaintops

Optical Telescopes in SpaceTelescopes in spaceHubble Space Telescope2.4 meters acrossCan detect very faint objects in space

The Electromagnetic SpectrumVisible light Light that we can seeNot the only form of radiation1852-James Clerk Maxwell proved that visible light is part of the electromagnetic spectrumMade up of all of the wavelengths of electromagnetic radiation

Detecting Electromagnetic RadiationEach color of light is a different wavelength of electromagnetic radiation.We can seeRed light-long wavelengthBlue light-short wavelengthRest of electromagnetic spectrum-radio waves, microwaves, infrared light, etc.Atmosphere blocks most invisible radiationCan pass through-radio waves, microwaves, visible light, etc.

Nonoptical TelescopesTo study invisible radiationDetect radiation that can not be seen by the human eyeEach type of radiation reveals different clues about an object

Radio TelescopesDetect Radio wavesMuch larger than optical telescopes radio waves are much longer than optical wavelengthsMost can be detected day and nightDoes not have to be solid

Linking Radio TelescopesMore detailed imagesWork like on large telescopeVery Large Array27 radio telescopes30km

Nonoptical Telescopes in SpaceMost blocked by the earths atmospherePut a lot of them in spaceChandra X-Ray ObservatoryDetects X-RaysMuch more sensitive

Mapping the StarsSection 3 VocabularyConstellationZenithAltitudeHorizonLight-yearPatterns in the SkyAncient cultures connected stars in patternsNamed sections of the sky based on the patternsSections of the sky that contain recognizable star patternsHelp navigate and keep track of timeDifferent civilization-different namesOrion

Constellations Help Organize the Sky/Seasonal ChangesA Region in the skyShares a border with its neighborLike statesEvery star or galaxy is located within 1 of 88 constellationsAs the Earth revolves around the sun, the apparent locations of the constellations change from season to season.

Finding Star in the SkyAstrolabe-can be used to describe the location of a star or planet-Used on relation to youNeed to know three points of referenceZenithAltitudeHorizonIf you want to describe a stars location in a relation to the Earth, you need to use the celestial sphere

The Path of Stars Across the SkyMost stars and planets rise and set throughout the night-apparent motion is caused by the Earths rotationPoles- the stars are circumpolarStars that can be seen at all times of the year and all times of nightThey never set.Different areas of the universe are visible

The Size and Scale of the UniverseLooking out a car window at treesObjects that are very far away do not appear to move at allSame for stars and planets1500s-Nicolaus Coperinicus noted that the planets appeared to move relative to each other but the stars did notThought that the stars must be much farther away than the planets

Measuring Distance in SpaceCopernicus was correct.Light-Year-Unit of length equal to the distance that light travels in 1 year9.46 trillion kilometersFarthest objects we can observe are more than 10 billion light-years away

The Doppler EffectCar HornDoppler Effect-also occurs with lightIf a light source is moving quickly away from an observer, the light emitted looks redder than it normally doesRedshiftIf a star is moving quickly toward an observer its light appears bluer than it normally doesBlushift

An Expanding UniverseHubble-analyzed the light from galaxies and stars to study the general direction that objects in the universe are movingLight from all galaxies except our close neighbors is affected by redshiftRapidly moving away from each otherAll galaxies except our close neighbors are moving apart, the universe must be expanding