ASTR 114 1st EditionExam # 1 Study Guide VocabularyStar - Large glowing ball of gas that produces heat and energyPlanet - Large object that orbits a star (Rocky, Icy, or Gaseous in composition) Moon - Object that orbits a planetComet - Small icy object that orbits a planetSolar (Star) System - A star and all material that orbits it Universe - Everything within and between all galaxies Constellations - Regions in the skyZenith - The point directly overheadHorizon - All points 90 degrees away from zenithEcliptic - The suns apparent path through the celestial sphere Circumpolar Stars - Stars that never setEclipse - looks like an elongated circleLunar Eclipse - when the moon appears red in the skyThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Speed - Rate at which an object movies (example: 10 miles/second) Velocity - Speed and direction (example: 10 miles/seconds, due east)Acceleration - Any change in velocity in units of speed/time (miles/second squared) Speed - Distance/TimeVelocity - Speed and DirectionForce - Mass x AccelerationWave - A pattern of motion that can carry energy without carrying matter along with it Wavelength - The distance between two wave peaksFrequency - The number of times per second that a wave vibrates up and down Atomic Number - Number of protons in nucleusRefraction - The bending of light when it passes through waterLecture OneSize of the universeThe distances between planets are huge compared to their sizes. It would take more than 3000 years to count the stars in the Milky Way Galaxy at a rate of one per secondThere are more stars in the sky than there are grains of sand on all of Earth’s beaches Light Years measure distance in reference to space One light-year is 5,910,000,000,000 miles Milky way = 1,000,000 light-years Lecture TwoStars at different distances all appear to lie on the celestial sphere The 88 official constellations cover the sphere Stars rise and set because of earths rotation Axis Tilt is the reason we have seasons on earth A sidereal day is earths rotation with respect to the stars, its 4 minutes shorter than a regular day A sidereal month is the 27.3 day orbit of our moonSidereal year is the time it takes to orbit the sunA tropical year is the cycle of seasons, it’s 20 minutes shorter than the sidereal year A solar day is longer than a sidereal day by about 1/360 because earth moves about one degree in orbit each day Lecture ThreeWe see phases of the moon because half the moon is lit by the sun half is in shadow, and its appearance to us is determined by the relative positions of Sun, Moon, and Earth. Lunar Eclipse is caused by earth’s shadow on the moon Solar Eclipse is caused by moon’s shadow on earth Moons orbit means eclipses occur during two periods each year We only see one side of the Moon is tidally locked with the Earth so it makes one rotation as it revolves around the Earth The Moon has lots of craters that are many different sizes Lecture FourModern science traces its roots to the greeks because they developed models of nature and emphasized that the predictions of models should agree with the observations. Copernicus: proposed a sun centered model of a solar system Determined the layout of the solar system Tycho: Made the most accurate naked eye measurements of planetary positions Thought that the earth had to be in the center of the solar systemHired Kepler, who used his observations to discover the truth about planetary motion Kepler: Discovered ellipses 1st law: Used for mars and Jupiter 2nd law: When planets were far away from the sun they went slower in orbit, when they got closer to the sun they moved faster3rd law: p^2 = a^3 Galileo: Said the earth was moving even though people who came before him said it was still Said that the phases of venus proved that the earth was not at the center of the universe All of his books were banned and he was undedicated by the church He solidified the Copernicus revolution Lecture FiveNewton changed our view of the Universe because he discovered laws of motion and gravitation 1st law of Motion - An object moves at a constant velocity unless a net force acts to change its speed or direction which is called inertia. 2nd law of Motion - Force = Mass x Acceleration 3rd law of Motion - For every force, there is always an equal and opposite forceLecture SixWay we interact with lightEmission: Low density cloud that emits at specific wavelengths, and depends on the temp. and compositionAbsorption: Cloud of gas that absorbs light at specific wavelength leaving dark absorption lines.waves - Carry energy without affecting matterlight - Carries electromagnetic wavesPhotons - Particles of light, the greater the frequency a photon has the more energy1 watt = 1 Joule/SecondWaves consist of wavelengths and frequency wavelengths given off by light transmits electromagnetic waves Speed of light = wavelength x frequency Longer waves = less frequency = less energyDoppler shift - tells us only about the part of an objects motion towards or away from us. Shorter wavelengths = blue shift Shorter wavelengths = red shift Humans cannot see most forms of light Lecture SevenMatter - Is made of atoms.Atoms - Are made of an electron cloud that has a nucleus in the center Atomic Number: numberof protonsAtomic Max Number: number of protons + neutrons Molecules: Mode from two different atomsIsotopes: Atoms that have the same number of protons, but a different number neutronsWhen Atoms move from excited level to ground state level there has to be an equal exchange Chemical fingerprints are all unique and they tell you what atoms are present and where they are exactly.Three Kinds of Spectra- Continuous Spectrum, Emission line spectrum, Absorption line spectrumLecture EightReflection - Telescopes that use mirrors, can be very large Refraction - Telescopes that use lenses, cannot be very large at all Angular Resolution - Larger = More detailed imageLight - Collection Area - Bigger = Better; the more light a telescope can receive the better the telescope• Refraction works in eyes, and cameras the same way it does in telescopes What Astronomers Do With TelescopesImaging: taking pictures of the sky Spectroscopy: breaking light into spectraTime Monitoring: Measuring how light output varies with timeLecture NineTurbulence in earths atmosphere causes distortion in our view of stars causing them to