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# Astronomy_Test1_Notes.docx

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School
Department
Physics
Course
PCS 181
Professor
Margaret Buckby
Semester
Winter

Description
Astronomy Chapter 1 NotesThe Scientific MethodThe Scientific Method a way of trying to make sense of the universe 1 Observation observe and try to understand 2 Hypothesis makean educated guess 3 Experiment set up an experiment 4 Conclusion draw a conclusion on previous hypothesis 5 Next step is that someone else has to do it it has to be reproducible from an independent researcher Electromagnetic Spectrum Astronomical information is transmitted by electromagnetic waves or starlightAstronomy is the only field you cannot take into the laboratory You can only observe and extract all possible informationStarlight tells us temperature chemical composition motion pressure magnetic fieldsEM SpectrumLight mutually perpendicular oscillating electric and magnetic fieldsLight moves in a wavelike pattern at a speed of c3 X 10ms cspeed of light Theory of relativity says nothing with mass can go as fast as the speed of lightWavelength distance between peaks of waves important because it determines colourTachyons theoretical fasterthanlight particlesEM Spectrum 1 X 10Default of lambda is wavelength of light EmcEenergy mmass cspeed of lightThere is a debate whether light is a little photon a burst of energy or a waveWhen testing whether light behaves like a wave or a particle it behaves according to the test you set out for it ie testing if it behaves like wave it behaves like a wave and viceversa Proven in the young or photoelectric test Wavelight dualityPhotoelectric theory shows how light behavesmoves like a particle Magnetic and electric fields are perpendicular to one another and velocity of light is perpendicular to the field Light gives us colourThe colour blue indicates a short wavelength while the colour red indicates a long wavelength In fact it is almost twice as long as blue To measure the wavelength of visible light the metre stick is too big It must be measured in nanometres which is a billionth of a metre stickShorter than 400nm is ultra violet light and is extremely dangerous to your vision Visible Colours ROY G BIV I stands for indigoOn test you must know the wavelength of red violet and green They are 700 400 and550respectivelyPhotons bundles of energylight as a particleWith white light mixture of all colours each wavelength gets bent at a different angle and white light is disbursed into different coloursWavelengths that are shorter than ultraviolet rays 400 are xrays and gamma rays Gamma rays come from nuclear reactions
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