Astro 7N PSU Exam Overview

Astro 7N PSU Exam 1 Newton's 1st Law An object at rest stays at rest unless acted upon by a force Newton's 2nd Law F=ma Newton's 3rd Law For every action, there is an equal and opposite reaction Strength of Gravity g=M/(R^2) Force of Gravity F=(M1M2/(D^2)) Sun's Movement East to West Due to Earth's rotation Phase Order of the Moon New --> Waxing Crescent --> First Quarter --> Waking Gibbous --> Full --> Waning Gibbous --> Third Quarter --> Waning Crescent --> New Full Moon Sun--Earth--Moon New Moon Sun--Moon--Earth Constellation Large defined area in the sky There are 88 Forms of Light Gamma, X-Ray, UV, Visible, Infrared, Microwave, Radio Bluer Color Short wavelength High frequency Redder Color Long wavelength Low frequency Continuum Spectrum Light at all wavelengths Absorption Spectrum Shows dark lines in the spectrum at certain wavelengths Produced by a gas cloud in front of a light source Absorption Line Dark lines in the spectrum at certain wavelengths Produced when photons are absorbed by electrons and the electrons move from a lower to higher energy level Emission Line Bright lines at specific wavelengths Due to emission of photons from atoms Produced when electrons jump from higher to lower energy levels Light-Gathering Power Important quality of a telescope Amount of light a telescope can gather Angular Resolution The ability of a telescope to distinguish two nearby light sources Atmospheric Problems Certain kinds of radiation can't get through the atmosphere so we can't see a clear picture from a telescope on the ground Atmosphere blurs Kepler's 1st Law The planets orbit the sun in elliptical orbits Kepler's 2nd Law A planet's speed is fastest when its closest to the sun and slowest when its farthest away Perihelion Orbital point nearest the sun Aphelion Orbital point farthest away from the sun Kepler's 3rd Law P^2=a^3 P= orbital period a= semimajor axis (average distance from the sun in AU) Mercury Smaller than Earth Extremely high temp on day side and extremely low temp on night side Lack of atmosphere Many craters Long day- 59 Earth days to rotate Short year- 88 Earth days to orbit Sun Venus Longer day (243 days) than its year (225 days) Rotates clockwise unlike most other planets 1/5 Dense atmosphere with mostly CO2 Very hot surface due to greenhouse gases Earth Thick atmosphere composed of N2 and O2 Mars Similar day and night schedule to Earth Half of Earth's diameter and 1/10 Earth's mass Thin atmosphere Cool surface temp (-65C) 2 moons Comets Few kilometers in size Made of ice and dust from solar system formation Highly elliptical orbits Move slowly across the sky Asteroids Made of rocks left over from planet formation Slightly elliptical orbit Most are less than 1km Move slowly across the sky Meteor Tiny dust particles or grains Less than 1cm in size Streak across the sky quickly Occur when an asteroid crosses Earth's orbit Meteorite A piece of meteor that survives atmospheric entry and lands on Earth Jupiter Small ring system Made up of hydrogen and helium High wind speeds Rapid rotation (10 hours) 12yr rotation around the sun Strong magnetic field Io 1 of Jupiter's moons Closest Active volcanoes Yellow color Europa 1 of Jupiter's moons Water/ice surface Liquid ocean below crust Ganymede 1 of Jupiter's moons Largest moon in the Solar System icy crust Callisto 1 of Jupiter's moons Farthest out Heavily cratered Saturn Ring structure More than 50 moons Titan Saturn's largest moon 2nd largest in solar system Too cold for life Uranus Long orbital period (84yrs) Thick atmosphere made of hydrogen and helium, some methane gives it a blue-green color Spin axis is 90 degrees off (likely caused by a collision) Moon Miranda Neptune Deep blue color Atmosphere of hydrogen, helium, methane Rapid winds Faint ring structure 14 known moons 2/5 Triton Largest moon of Neptune Atmosphere made of nitrogen and methane Kuiper belt Disk-shaped region beyond Neptune, ranges 30-55 AU Oort Cloud Houses long-period comets Beyond Kuiper belt Planet Considerations 1. Orbit the sun 2. Massive enough to be round 3. Clear region around orbit Terrestrial Planets Mercury, Venus, Earth, Mars Earth-sized or smaller Long day Short year Close to the Sun Close to each other High density Generally warmer Few moons Jovian planets Jupiter, Saturn, Uranus, Neptune Much larger than Earth Short day Long year Very far apart Low density Cold All have ring structure Many moons Gray with numerous craters Mercury Bright yellow, no sharp features, no rings Venus Gray and cratered with distinctive large dark spots Luna Red, white pole caps Mars 3/5 Asteroid, non spherical Vesta Stormy stripes Jupiter (I've seen better looking pizzas Io Pale and covered in fine cracks, smooth looking Europa Marbled look Ganymede Darker and more cratered Callisto Large ring system Saturn Titan Saturated orange with complete cloud cover 4/5 Distinct blue green, tipped on its side Uranus dull and gray with wrinkled look Miranda Deep blue, few dark rings Neptune Triton Pluto and Charon 5/5