Astr 1101 test 3 review Doppler effect Radial motion line of sight movement Transverse motion across the line of sight Objects moving towards each other o Compressed waves o Wavelength shorter light bluer Objects moving away from each other o Stretched waves o Wavelength longer light redder Doppler shift equation o Change in wavelength Emitted rest wavelength Speed of light o Velocity of source Telescopes 2 main types o Refracting uses lenses gathering light o Reflecting uses mirrors gathering light 3 main functions o Gather light o Refine detail o Magnify not as important Velocity positive for redshifted negative for blueshifted Refracting o Lights changes speed as it moves through lenses and forces it to bend Reflection Resolving power o How fine of detail o Increasing size of telescope increases resolving power Different kinds of telescopes in different places Earth s atmosphere blocks some radiation out Longer wavelengths are easy to absorb while shorter wavelengths are blocked o Some types of waves can only be detected at certain elevations o All wavelengths can be seen in space Some telescopes are placed in space above Earth s atmosphere because the light from stars can be blocked from Earth s atmosphere Other light Infrared o Allows us to see through objects o Used in night vision cameras o Actually pick up temperature Warm bright Cold dark o Astronomers use infrared to see planets Planets don t create any light of their own almost impossible to see next to a bright star Planets give off their own light in infrared Our star the sun Heat transport o Conduction Transfer through direct contact Transfer through another object o Convection o Radiation Transfer via photons Energy generation o Nuclear reactions Fusion combing atoms together Fission breaking atoms apart o Neutrino Nearly massless particles Escape the sun easily Result of fusion inside of sun Help us to understand sun s processes Sun s atmosphere o Photosphere cool thin low density bottom layer 500 km thick sunspots caused by magnetic field dark because it s cooler than surrounding o Chromosphere Hot low density gas Middle layer o Corona Hot extremely low density gas Top layer o Magnetic field Cause mass ejection Prominences big gaseous feature escaping the sun Flares little gaseous feature escaping the sun Energy is created in the sun via fusion of light elements into heavier ones Earth s atmosphere and the Human effect Rayleigh scattering o Reason the sky is blue sunset is red o Atmosphere scatters blue light more effectively than red light Human s effect on Ozone o Human s particularly caused destruction by using chlorofluorocarbons CFC s o Ozone blocks much of UV light in atmosphere o Montreal Protocol Worldwide treaty to phase out CFC s Photons change from high to low energy o Photons pass through atoms o Atoms can absorb energy from photon o Atom gains energy while photon loses Runaway Greenhouse effect o Greenhouse gases increase trap in more heat o Surface warms Ice melts rocks outgas plants die Effects of rising temperatures of heat o Shrinking melting of polar ice caps Reduces reflection of sunlight o Wild weather swings o More evaporation of water o Greenhouse gases increase trapping more and more heat CO2 absorbs lots of infrared radiation meaning it holds in lots Why does a shirt look red The shirt absorbs all colors of visible light except for red which it reflects What happens to light that is absorbed It gets reradiated in the infrared radiation which is why items left in the sun get hot Going Green Phantom energy stand by power o Energy used when an electronic is not actually turned off but on stand by If it has a light on or is warm it s using power The best current solution is to cut back on emissions and plant lots of trees while we work on other methods Earth s Changing Surface Three types of rocks Igneous Sedimentary Metamorphic Seismology 2 kinds of waves o P waves o Formed from magma or lava o Formed by deposition of material usually by water o Formed by physical or chemical change due to heat and pressure Result from compression and stretching Refract between Earth s layers o S waves Vibrate up and down Looks like a sound wave Don t travel through liquids Tectonic shifts o Since Earth s core is very hot heat transfers to mantle and causes convection currents o Tectonic plates ride on mantle Volcanoes are usually found in places where earthquakes occur from oceanic plates colliding with continental plates The change in position of the continents over time is primarily caused by the mantle material circulating inside Earth The Moon from meteor impact Maria seas Tycho crater crater with rays coming from sides because of debris ejected o Dark areas o If crater gets deep enough lava can eventually well up through cracks in crust and resurface crater Lunar highlands o Lighter areas Radioactive dating object Ages for solar system o Uses half life of different elements to find out the total age of the o Almost all meteorites 4 56 billion years old o Oldest Earth rocks are 4 billion years old The mare on the moon has fewer craters than the highlands This is because the mare have been resurfaced and thus are younger Flying space objects Asteroids big objects in space Meteoroids smaller objects in space Meteors passing through the atmosphere Meteorites on the ground Regolith the dust that s on the moon What does the Earth have that moon doesn t t to limit craters o Atmosphere friction burns up meteors o Weather wind and rain erode craters o Oceans o Geologic activity Chicxulub impact crater killed dinosaurs Ways to defend Earth from asteroids o Blow up nuke near it Try to vaporize asteroid with radiation Reflects more light changes radiation pressure over time o Paint it white shifts orbit o Pull it Park huge satellite near it gravity will pull asteroid to satellite Terrestrial Planets Mercury Weird terrain result of shockwaves that traveled through the planet o Similar to moon o Some resurfacing due to lava flow o Suffers from shrinkage Mantle cooled off and the planet contracted o Long days and long nights Venus Earth s evil twin o Very thick atmosphere Thick clouds Mostly CO2 Almost no water vapor o Rotates backwards o Probably had water Mars o Little atmosphere o Red because of rust on surface Southern highlands Heavily cratered Northern lowlands Smooth o Used to have water