Astronomy (7.7-7.15) The expanding universe Astronomy topic 7 (7.7 - 7.15) 5.0 / 5 based on 1 rating ? PhysicsAstronomyGCSEEdexcel Created by: EmmathorpeeCreated on: 22-12-20 10:31 Red Shift - Element present in stars Light from stars does not emitt all wavelength as some are absorbed by elements in the star So dark lines are present when spectrums of stars are analysed → so we can see what element are present in the star 1 of 6 Red Shift - Galaxies + Speed When the specrum of light from distant galaxies is observed dark lines show and increase in wavelength and decrease on frequency Lines are shifted to red end of spectrum so it is called red shift Most galaxies emitt red shifted light The space between Earth and the galaxy is expanding and the light waves are being stretched on the journey This shows that the galaxy is moving away from earth, the more red-shifted the light is the faster the galaxy is travelling from earth 2 of 6 Theories of the Universe - Big bang theory 13.8 billion years ago the universe was a very small, hot region of dense matter From this point everything expanded into the universe today Multiple peices of evidence to back this up 3 of 6 Theories of the Universe - Evidence from Red shift The further away a galaxy is the more red shifted the light from it is The further away the galaxy is the faster they are moving Similar to an explosion→ fastest pieces travel furthest Provides evidence that the universe, including space itself, is expanding 4 of 6 Theories of the Universe - Evidence from CMBR Cosmic Microwave Background Radiation Comes form all directions in space and has a temp of -270C It is the remains of thermal energy from the Big Bang spread thinly across the while universe Was discovered after a theory predicted it and is strong evidence of the Big Bang Theory 5 of 6 Theories of the Universe - Steady state theory Theory that the universe has always existed and is slowly expanding and creating matter over time. It is supported by res shift but not CMBR and lost support after discovery of CMBR 6 of 6
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